| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Internal Medicine, Justus-Liebig-University, 35385 Giessen, Germany
 |
ABSTRACT |
|---|
 TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
In 49 acute respiratory distress syndrome (ARDS) patients, the phenotype of alveolar macrophages (AMs) was analyzed by flow cytometry. Bronchoalveolar lavage (BAL) was performed within 24 h after intubation and on days 3-5, 9-12, and 18-21 of mechanical ventilation. The 27E10high/CD11bhigh/CD71low/ 25F9low/HLA DRlow/RM3/1low AM population in the first BAL indicated extensive monocyte influx into the alveolar compartment. There was no evidence of increased local AM proliferation as assessed by nuclear Ki67 staining. Sequential BAL revealed two distinct patient groups. In one, a decrease in 27E10 and CD11b and an increase in CD71, 25F9, HLA DR, and RM3/1 suggested a reduction in monocyte influx and maturation of recruited cells into AMs, whereas the second group displayed sustained monocyte recruitment. In the first BAL from all patients, monocyte chemoattractant protein (MCP)-1 was increased, and AMs displayed elevated MCP-1 gene expression. In sequential BALs, a decrease in MCP-1 coincided with the disappearance of monocyte-like AMs, whereas persistent upregulation of MCP-1 paralleled ongoing monocyte influx. A highly significant correlation between BAL fluid MCP-1 concentration, the predominance of monocyte-like AMs, and the severity of respiratory failure was noted.
alveolar macrophages; monocyte chemoattractant protein-1; fluorescence-activated cell sorting; cell surface molecules
| |
INTRODUCTION |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
THE RECRUITMENT of leukocyte populations is one of the fundamental mechanisms involved in inflammatory processes. Neutrophil influx into the alveolar space has long been known in acute respiratory distress syndrome (ARDS) and severe pneumonia (10, 14, 31), but excessive expansion of the alveolar mononuclear phagocyte population in ARDS has also been reported (35). It has recently been suggested that local proliferation causes expansion of the alveolar macrophage (AM) population in inflammatory lung disease (5), but there is growing evidence that enlargement of the AM pool in sarcoidosis (18), hypersensitivity pneumonitis (20), idiopathic lung fibrosis (ILF) (22), and human immunodeficiency virus (HIV)-related pulmonary disease (42) is attributed to the recruitment of peripheral blood monocytes into the lung. These AM precursors were identified by their immature monocyte-like immunophenotype, and augmented release of proinflammatory mediators was ascribed to these cells (3, 22, 43).
Monocyte chemoattractant protein (MCP)-1 belongs to the supergene family of C-C chemokines located on chromosome 17 and has specificity for the recruitment of mononuclear leukocytes (24). Elevated MCP-1 levels in bronchoalveolar lavage (BAL) fluids have been demonstrated in patients with sarcoidosis, ILF (9), hypersensitivity pneumonitis (38), and ARDS (16). In addition to its role as a chemoattractant, MCP-1 may participate in the pathogenesis of monocyte-mediated lung injury by activating mononuclear phagocytes through the generation of receptor-mediated calcium influx (33), increasing the release of reactive oxygen species (41), and modulating the adhesion properties of these cells (40). MCP-1 expression in monocytes is induced by transendothelial migration (39) and interaction with extracellular matrix proteins (27). Thus one might speculate that extravasated monocytes themselves trigger sustained monocyte recruitment and promote ongoing inflammation.
In the present study, we employed fluorescence-activated cell-sorting (FACS) analysis for detailed immunophenotyping of the alveolar space mononuclear phagocyte population in acute lung injury. Sequential BAL was performed in patients with ARDS induced by sepsis, pancreatitis, or pneumonia. We analyzed the expression of monocyte differentiation, maturation, and activation markers; BAL fluid MCP-1 levels; and AM MCP-1 gene expression and inquired about a correlation between alveolar monocyte recruitment and MCP-1 levels and lung injury in these patients.
| |
MATERIALS AND METHODS |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
Study population. Patients included in the present study were recruited from the intensive care unit of the Department of Internal Medicine, Justus-Liebig-University (Giessen, Germany). Healthy volunteers and mechanically ventilated patients suffering from cardiogenic lung edema (CLE) served as control groups. The study was approved by the local ethics committee, and written informed consent was obtained from all participants or the patient's closest relatives.
All patients were mechanically ventilated; the inspired O2 fraction (FIO2) and respirator settings, including positive end-expiratory pressure, were chosen according to the requirements of pulmonary insufficiency. General therapeutic approaches included nutrition, volume substitution, and antibiotics. Vasoactive or inotropic drugs were administered according to hemodynamic variables as determined by right heart catheterization. In all patients, the first BAL was performed within 24 h after intubation. The second BAL was performed on days 3-5, the third on days 9-12, and the fourth on days 18-21, when possible, after the onset of mechanical ventilation. General exclusion criteria for entry into this study were cancer, interstitial lung disease, and HIV infection. BAL was performed in 16 patients with ARDS after sepsis or pancreatitis and in 33 patients with pneumonia-induced ARDS (ARDS/PNEUMONIA; Table 1). The general criteria for the diagnosis of ARDS were roentgenographically diffuse and bilateral alveolar infiltrates, pulmonary capillary wedge pressure < 16 mmHg, and the absence of acute or chronic left heart failure. First and second BALs were performed in 49 patients, 39 patients underwent a third BAL, and only 18 patients underwent a fourth BAL due to prior extubation or death.
|
BAL.
Bronchoscopy and BAL were performed by means of a fiber-optic
bronchoscope, with 10 aliquots of 20 ml of warm sterile saline being
infused into one segment and removed by gentle suction (35-60% recovery in ARDS patients, 65-85% recovery in healthy volunteers, and 78-113% recovery in patients with CLE). Lavage fluid was
filtered through sterile gauze, collected on ice, and immediately
centrifuged at 200 g at 4°C for 10 min to sediment BAL
fluid cells. The cells were counted with a hemocytometer, viability was
assessed by trypan blue exclusion, and differential cell counting was
performed in Pappenheim-stained cytocentrifuge preparations.
Supernatant aliquots were frozen in liquid nitrogen and stored at
80°C for subsequent cytokine measurements.
Immunofluorescence staining of BAL fluid cells. Immunofluorescence labeling of BAL fluid cells was performed as previously described (25). Briefly, 2 × 105 cells were distributed to each well of flexible round-bottom microtiter plates (Falcon, Heidelberg, Germany) and washed with PBS (Sigma, Munich, Germany) containing 0.1% BSA (Sigma) and 0.02% sodium azide (NaN3; Merck, Darmstadt, Germany). Before the addition of monoclonal antibodies, 20 µl of a human immunoglobulin preparation (Behring, Marburg, Germany) were added to block AM FcIgG receptors. Saturating amounts of antibodies directed against CD14 (My4, Coulter Immunology, Hialeah, FL), CD71 (OKT9, Ortho, Raritan, NJ), HLA DR (L243, Becton Dickinson, San Jose, CA), 25F9 (45), 27E10 (3), RM3/1 (Dianova, Hamburg, Germany; 46), CD11b (M522; 26), MHC I (positive control, W6/32.HL, generously provided by A. Ziegler, Humboldt University, Berlin, Germany; 1), or isotype controls (negative control; Dianova) were added and incubated for 30 min at 4°C. The plates were washed twice with PBS and incubated with biotin-labeled F(ab')2 fragments of sheep anti-mouse immunoglobulin antibodies (Biozol, Munich, Germany) for 30 min on ice. In a further 30-min incubation step, biotinylated secondary antibodies were developed with streptavidin-coupled phycoerythrine-cyanine 5-tandem conjugate (TriColor, Medac, Hamburg, Germany). This technique circumvents the problem of autofluorescence imposed by the AMs. After two final washes, the cells were resuspended in PBS and kept on ice until flow cytometric analysis.
Quantification of proliferating AMs. The monoclonal antibody Ki67 (Dianova) was used for the quantification of proliferating AMs in ARDS patients and healthy control subjects. Immunocytochemical staining was performed on cytospins of BAL fluid cells with an immunoalkaline phosphatase technique [alkaline phosphatase-anti-alkaline phosphatase (APAAP)] as previously described (12). Briefly, cytospins were incubated with the Ki67 antibody followed by rabbit anti-mouse Ig (DAKO, Glostrup, Denmark), APAAP complexes, and the alkaline phosphatase substrate (Dianova). Counterstain was performed with Gill's hematoxylin (Sigma). Finally, the percentage of positive cells was estimated from 200 AMs.
Flow cytometric phenotyping of AMs.
Flow cytometry was performed with the use of a FACStarPLUS
flow cytometer from Becton Dickinson equipped with a 5-W argon-ion laser operating at 488 nm and 200 mW. AMs were gated by dual light scatter and autofluorescence characteristics. The data on forward- and
right-angle light scatter, green autofluorescence, and TriColor fluorescence intensity were recorded for 104 cells on the
FACStarPLUS data-handling system and further analyzed with
PC-LYSYS research software (Becton Dickinson). Specific TriColor
fluorescence distribution of the AMs is expressed as the fluorescence
intensity index [fluorescence intensity index of MAb = (MFI of
MAb MFI of isotype)/(MFI of W6/32.HL MFI of isotype),
where MFI is the mean fluorescence intensity corrected for the negative
control and signal-to-noise ratio values and MAb is the monoclonal
antibody].
Flow sorting of AMs. AMs from healthy control subjects and from the first BAL of ARDS patients were separated by flow sorting with the FACStarPLUS flow cytometer described in Flow cytometric phenotyping of AMs. A 100-µm ceramic nozzle was attached to a large-nozzle sort-head assembly (MACROsort, Becton Dickinson), which is specially designed for the separation of large biological particles. The cytometer was adjusted to a sheath pressure of 8.5 psi and a transducer frequency of 17.164 kHz, flow rate was 400 events/s, and droplet delay was 15.2-15.7 with two deflected droplets. AMs were separated from granulocytes and lymphocytes by forward- and right-angle light-scatter properties and autofluorescence characteristics. Before the cells were sorted, the sample line tubing was sterilized with 70% ethanol and subsequently flushed with sterile normal saline. Unsorted cell suspensions and sorted AM preparations were maintained on ice throughout the separation procedure. The sheath fluid was routinely assayed for endotoxin content by the use of a Limulus lysate assay (COATEST Endotoxin, Chromogenix, Mölndal, Sweden) and always ranged <10 pg/ml. These sorting conditions have been shown to prevent artificial, isolation-induced cytokine production by AMs (28). FACS separation of AMs obtained from BAL samples always yielded purities of >96%. The viability of flow-sorted AMs was consistently >90%.
Ex vivo AM MCP-1 gene expression.
Total cellular RNA from flow-sorted AMs (1 × 106 AMs
each) was isolated with the acid guanidinium
thiocyanate-phenol-chloroform method as previously described
(11). The constituent mRNA was reverse transcribed
according to the instructions of the manufacturer (StrataScript RT-PCR
kit, Stratagene, Heidelberg, Germany) in a final volume of 25 µl. The
synthesis of cDNA was carried out in a GeneAmp PCR System 2400 (Perkin-Elmer, Norwalk, CA) for 50 min at 37°C, and enzyme
inactivation was achieved by heating the reaction to 94°C for 7 min.
Subsequently, the reaction mixture was diluted with RNase-free water to
60 µl and stored at 80°C until used. The PCR was performed in 1×
PCR buffer (Perkin-Elmer), 1 mM each deoxynucleotide triphosphate
(dATP, dCTP, dGTP and dTTP), 1 µM intron-spanning specific primers
(
-actin, 5'-AAAGAACCTGTACGCCAACACAGTGCTGTCT-3' and
5'-CGTCATACTCCTGCTTGCTGATCCACATCTG-3', and MCP-1,
5'-TGAAGCTCGCACTCTCGCCT-3' and 5'-GTGGAGTGAGTGTTCAAGTC-3'; Stratagene),
0.75 U of AmpliTaq DNA polymerase (Perkin-Elmer), and 2 µl
of first-strand cDNA in a total volume of 25 µl. PCR profiles
consisted of initial denaturation at 94°C (1.5 min) followed by 25 (-actin) or 35 (MCP-1) cycles of denaturation (94°C for 50 s), primer annealing (60°C for 60 s), and primer extension
(72°C for 60 s) in a GeneAmp PCR System 2400. The final
extension was performed at 72°C for 7 min. Aliquots of PCR products
were electrophoresed through 1.8% (wt/vol) NuSieve-agarose gels
stained with ethidium bromide for ~2 h at 75V. Negative controls were
routinely performed by running PCR without a cDNA template to exclude
false-positive amplification products. Positive controls were performed
with cDNA preparations obtained from lipopolysaccharide (LPS)-stimulated AMs. To verify the specificity of PCR amplifications obtained from the above-mentioned procedure, automated DNA sequencing was carried out on the purified cDNA samples according to the instructions of the manufacturer (model 373 A, Applied Biosystems, Darmstadt, Germany). By comparing the resulting DNA sequences with the
corresponding published sequences, we identified PCR products as
expected segments of spliced MCP-1 or -actin mRNA species. With PCR
conditions optimized for primer and magnesium concentrations and cycle
number, amplification of cDNA samples was verified to be in the
exponential phase of PCR by comparing the amount of input RNA
equivalents with the yield of the MCP-1 and -actin PCR products. The
specific MCP-1 product was quantified as previously described
(6) with some modifications. Briefly, with -actin as a
housekeeping gene, input cDNA concentrations of different samples were
adjusted with distilled water to obtain comparable cDNA contents before
PCR amplification. Aliquots of unlabeled MCP-1 and corresponding
-actin PCR products were denatured at 94°C for 5 min before being
blotted onto nylon membranes (32). Membranes were baked at
80°C for 2 h, prehybridized, and hybridized in 10 ml of buffer
composed of 5× saline-sodium citrate, 5× Denhardt's solution, 1%
sodium dodecyl sulfate (Sigma), 50% deionized formamide (Clontech,
Palo Alto, CA), and heat-denatured salmon sperm DNA (Boehringer
Mannheim) at 42°C overnight with respective probes that were labeled
with [
-32P]dCTP by random hexamer priming
(15). Spin column chromatography (Boehringer Mannheim) was
used to remove unincorporated deoxynucleotide triphosphates as well as
small probe fragments. After two washes, quantification of MCP-1 gene
expression levels was performed with the use of a PhosphorImager SF
(Molecular Dynamics, Sunnyvale, CA). The results are expressed as mean
ratios normalized to -actin signals.
BAL fluid MCP-1 levels. MCP-1 protein in BAL samples was measured with the ELISA technique. Maxisorp microtiter plates (Nunc, Wiebaden, Germany) were coated overnight at 4°C with polyclonal goat antibodies to human MCP-1 (R&D Systems, Abingdon, UK) followed by three washing steps with PBS containing 0.05% Tween 20 (Sigma). Fifty-microliter samples of BAL fluid were dispensed into the wells and incubated for 2 h at room temperature. After being washed, application of a mouse monoclonal antibody directed against MCP-1 (R&D Systems) was followed by sequential incubation with a biotinylated donkey anti-mouse Ig antibody (Dianova), avidin and biotinylated horseradish peroxidase (DAKO), and the substrate 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS; Sigma). Serial dilutions of human recombinant MCP-1 provided a standard curve for each individual ELISA. Plates were read at 405 nm with an ELISA photometer. Quantification of each cytokine was performed in triplicate, with detection ranges of 10-1,000 pg/ml.
MCP-1 bioassay. Human monocytes were isolated by a combination of Ficoll (Sigma) density gradient centrifugation and counterflow elutriation (Beckman Instruments, Palo Alto, CA). The isolated monocytes (purity 90-95%) were radiolabeled with 5 µCi of 111In (10 mCi/ml of 111InCl3; Amersham, Braunschweig, Germany) tropolon (Fluka Chemical, Hauppauge, NY) as previously described (13). Human pulmonary artery endothelial cells (5 × 104, passages 4 and 5; Clonetics, San Diego, CA) were seeded onto 5-µm pore size Transwell inserts (diameter 6.5 mm; Costar, Cambridge, MA) and grown to confluence in 4-5 days. BAL supernatants from healthy control subjects and ARDS patients were added to the lower compartments in the absence and presence of a neutralizing mouse anti-human MCP-1 antibody (R&D Systems), and 1 × 106 radiolabeled monocytes were added to the filter inserts of Transwell chambers. After 120 min, the monocytes from the lower compartment were collected and counted in a gamma counter (Packard Canberra, Frankfurt, Germany), and the number of monocytes that migrated through the endothelial barrier is expressed as a percentage of counts in the lower compartment in relation to the counts initially added to the upper compartment.
Statistical analysis. Differences among the study groups were analyzed with the Kruskal-Wallis test followed by Dunn's multiple contrast hypothesis or the Wilcoxon-Mann-Whitney test considering Bonferroni's correction. For correlation of AM maturity and immaturity markers with BAL fluid MCP-1 concentration and oxygenation index [arterial PO2 (PaO2)/FIO2], the data were log transformed to achieve normal distribution as assessed by the Kolmogorov-Smirnov test. P values < 0.05 were considered to represent a significant difference. Statistical procedures were performed with the SPSS for MS Windows analysis system.
| |
RESULTS |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
AM phenotype and MCP-1 levels in healthy control subjects, patients
with CLE, and in first BAL of ARDS patients.
In the first BAL after the onset of mechanical ventilation, a
significant increase in total cell count and a massive neutrophil influx were noted in all patients with ARDS (Table
2). Compared with that in the healthy
control subjects, the percentage of AMs was decreased in ARDS patients,
but absolute cell counts revealed a significant expansion of the AM
population (Table 2). AM and neutrophil counts in patients with ARDS
after sepsis or pancreatitis were not significantly different from the
cell counts in ARDS/PNEUMONIA patients. In CLE patients, absolute cell
counts were not different from those in healthy control subjects, but
neutrophil granulocytes were significantly increased (Table 2).
|
|
|
12-fold (mean; range 4- to 27-fold) higher cytokine concentrations. However, statistical analysis of these urea-corrected data did not reveal any previously unobserved differences (data not
shown). Monocyte-specific chemotactic activity in the first BAL fluid
from ARDS patients was significantly upregulated compared with that in
healthy control subjects (Fig. 3), with no significant difference
between ARDS and ARDS/PNEUMONIA patients. This monocyte-specific chemotactic activity was nearly completely reduced to control levels by
a neutralizing antibody against human MCP-1 (Fig. 3). BAL fluid MCP-1
levels in CLE patients were not significantly different compared with
those in healthy control subjects (77 ± 59 pg/ml;
P = 0.32; n = 8).
|
-actin ratio differed significantly
from the control value, without a statistical difference between ARDS
and ARDS/PNEUMONIA patients (Fig. 3).
AM phenotype and MCP-1 levels in sequential BALs from ARDS
patients.
AM absolute cell counts increased, whereas neutrophil cell counts
slightly decreased in sequential BAL from ARDS patients (Table
3), with no significant difference
between ARDS and ARDS/PNEUMONIA patients. Immunophenotyping of AMs in
the course of sequential BALs revealed two distinct patient groups. The
first subgroup (subgroup A; Figs.
4 and 5; a
representative FACS analysis is presented in Fig.
6) displayed pronounced downregulation of
27E10 and CD11b and significant upregulation of CD71, HLA DR, and 25F9, i.e., a transition of the predominance of immature to mature
phenotype. In addition, expression of RM3/1, the monocyte/macrophage
marker associated with the downregulatory phase of the inflammatory
process, was markedly increased. A biphasic course was noted for CD14. It was significantly decreased on AMs obtained from the second BAL
compared with those from the first BAL, healthy control subjects, and
CLE patients. In the following lavages, CD14 was again upregulated but
did not surpass the expression level of AM from healthy control subjects or CLE patients. The second subgroup (subgroup B;
Figs. 4 and 5) exhibited prolonged predominance of the immature
phenotype in the course of sequential BALs, indicated by a continuously elevated expression of 27E10 and CD11b on AMs and the absence of CD71,
25F9, RM3/1, and HLA DR upregulation on these cells. CD14 was
persistently downregulated in these subgroups.
|
|
|
|
|
|
Correlation with the clinical data.
In ARDS patients, the expression of AM immaturity markers correlated
inversely with lung function given as
PaO2/FIO2
(shown for 27E10 in Fig. 8; CD11b: r = 0.62;
P < 0.01; n = 155 samples), and the
expression of "maturity" markers correlated positively with the
oxygenation index (CD71: r = 0.66, P < 0.01; 25F9: r = 0.71, P < 0.01; RM3/1:
r = 0.59, P < 0.01, HLA DR:
r = 0.64, P < 0.01; n = 155 samples). When individual days of sequential BAL were analyzed,
the correlation of the immaturity marker 27E10 with
PaO2/FIO2 was
r = 0.52 (P < 0.05;
n = 49 samples) in the first BAL, r = 0.6 (P < 0.05; n = 49 samples) in
the second BAL, r = 0.55 (P < 0.05;
n = 39 samples) in the third BAL, and r = 0.54 (P < 0.05; n = 18 samples) in
the fourth BAL. The correlation of
PaO2/FIO2
with the maturity marker CD71 was r = 0.53 (P < 0.05; n = 49 samples) in
the first BAL, r = 0.62 (P < 0.05;
n = 49 samples) in the second BAL, r = 0.49 (P < 0.05; n = 39 samples) in the third BAL, and r = 0.53 (P < 0.05;
n = 18 samples) in the fourth BAL. The overall survival
in ARDS patients was 63.3% (31 of 49 patients). In the subgroup with a
progressive transition to mature AMs and a decrease in MCP-1 levels in
sequential BAL, 28 of 37 patients (75.7%) survived. The survival rate
was only 25% (3 of 12) in patients with a sustained predominance of
immaturity markers on AMs and elevated MCP-1 levels.
| |
DISCUSSION |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
The present study shows that in addition to the well-known phenomenon of neutrophil recruitment, there is an early profound expansion of the sessile pool of AMs, with an impressive shift from a mature to an immature cell type in both ARDS after sepsis or pancreatitis and ARDS caused by severe pneumonia. Immunophenotyping of the alveolar mononuclear phagocytes, together with the demonstration of a lack of increased local proliferation, strongly suggests that a rapid influx of monocytes from the vascular compartment represents the predominant underlying event. In addition, evidence is presented that upregulation and secretion of MCP-1 in the alveolar compartment may be centrally linked to this process. Interestingly, a state of sustained monocyte influx was found to be significantly correlated with the severity of respiratory failure.
As anticipated for sessile mature macrophages, the alveolar mononuclear phagocyte population of healthy control subjects was characterized by a 27E10low/CD11blow/CD71high/HLA DRhigh/25F9high/RM3/1high phenotype profile (4, 18, 20, 30, 45). This contrasted sharply with the profile of 27E10high/CD11bhigh/CD71low/HLA DRlow/25F9low/RM3/1low, which was consistently noted in the early lavage fluids of ARDS patients and represents a monocyte-like immunophenotype. In parallel with the observation of an overall increase in BAL fluid total AM numbers, these findings suggest that the rapid expansion of the AM population was predominantly caused by an influx of monocytes. This view is further supported by the analysis of forward scatter properties, demonstrating smaller average cell size in the initial lavage fluids from ARDS patients and by the lower autofluorescence characteristics of these cells. The monocyte-like population of AMs in ARDS patients revealed exceptional upregulation of the calprotectin complex 27E10, a heterodimer of the calcium-binding proteins MRP8/MRP14, which are only present on inflammatory acute-phase macrophages (3) and which have previously been shown to be upregulated on AMs in pneumonia (36). No evidence for increased local proliferation of AMs in ARDS patients was obtained as judged by nuclear Ki67 staining. Such local AM replication has been suggested as an alternative mechanism that may increase AM numbers in the alveolar space (5).
Because all patients with ARDS were lavaged under conditions of mechanical ventilation in contrast to healthy control subjects, one might argue that this therapeutic intervention rather than the underlying lung inflammatory disease might be responsible for the alveolar monocyte influx. Because the AM phenotype of mechanically ventilated patients suffering from CLE closely resembled the AM phenotype of healthy control subjects, respirator therapy as well as lung edema formation per se may not be responsible for the marked alveolar monocyte recruitment in ARDS patients.
Performance of sequential BAL over 2-3 wk after the onset of respirator therapy showed the appearance of two distinct groups of ARDS patients. The larger subgroup was characterized by a progressive disappearance of the monocyte-like alveolar mononuclear phagocyte population concomitant with an increasing predominance of the mature AM phenotype. In addition, enhanced expression of RM3/1, a marker present on inflammatory late-phase monocytes/macrophages (46), was noted. These findings clearly suggest a decrease in monocyte influx into the alveolar space in these patients. In contrast, the other subgroup displayed evidence for sustained monocyte recruitment, with persistent predominance of the immature AM phenotype profile. Interestingly, these immunophenotype features were highly significantly correlated with the severity of disease, and a tendency toward higher mortality with presumed ongoing influx of monocytes was found in the subgroup.
In contrast to the other immunophenotype markers, the course of CD14 expression on AMs in sequential BAL was more complex. Clearly elevated in the initial BAL, CD14 expression sharply dropped and subsequently increased again toward normal values in the patients with a predominance of AM maturation, whereas the CD14 levels remained low in the second to fourth BAL fluids from patients with presumed ongoing monocyte influx. The expression of the LPS/LPS-binding protein receptor on myeloic cells seems to be subject to a complex regulatory mechanism because monocyte maturation either increased or decreased CD14 expression depending on the microenvironment of the cell (19, 44). Such complex regulation was also suggested to underlie the observation of both enhanced and depressed AM CD14 expression in sarcoidosis (18, 20, 37). Without being able to elucidate the regulation of CD14 in the present study in more detail, the fact that the control values of CD14 expression, with a progressive appearance of mature AMs, were noted in later BAL samples from ARDS patients further supports the notion of a normalization of the alveolar mononuclear phagocyte population in these subgroups.
Elevated MCP-1 levels in BAL fluid have been previously demonstrated in
patients with sarcoidosis (9), ILF (9), and ARDS (16). The present study offers strong evidence of a
major role for MCP-1 in alveolar monocyte recruitment under the
currently investigated conditions of ARDS. First, in parallel with the
appearance of immature monocyte-like AMs in the alveolar compartment,
the initial BAL fluid MCP-1 levels were increased in all patients with
acute inflammatory lung injury, and the BAL fluid of ARDS patients
displayed increased monocyte chemotactic activity. This monocyte-specific chemotactic activity was significantly reduced by a
neutralizing anti-MCP-1 antibody. BAL fluid MCP-1 concentrations were
also measured in patients requiring mechanical ventilation due to CLE,
and MCP-1 levels in these patients were not different from those in
healthy control subjects, suggesting that lung inflammation rather than
respirator therapy or lung edema formation caused the alveolar space
MCP-1 response. Second, the patient subgroup presenting a decrease in
monocyte-like AMs in sequential BAL exhibited a marked decline in MCP-1
to near control values, whereas the subgroup displaying evidence for
sustained monocyte influx showed continuously elevated or even further
increased BAL fluid MCP-1 levels. Third, when analyzed for all ARDS
patients independent of the affiliation to the different subgroups,
there was a highly significant correlation between a monocyte-like
immunophenotype of the AM population and BAL fluid MCP-1
concentrations. Fourth, concomitant with elevated MCP-1 protein levels
in the initial BAL, flow-sorted AMs from ARDS patients showed
extensively upregulated MCP-1 gene expression. These data, obtained
under clinical conditions, are well in-line with investigations in
experimental lung injury, suggesting that the induction of MCP-1 in AMs
may be a major contributor to the recruitment of peripheral blood
monocytes into the alveolar compartment (7,
8, 21). MCP-1 has previously been shown to be
sufficient for the transmigration of monocytes across the alveolocapillary barrier in a transgenic mouse model (17),
which, of course, does not deny a substantial contribution of other
monocyte-specific chemokines (23). Peripheral blood
monocytes do not express MCP-1 message constitutively, but this is
strongly induced by transendothelial migration (39) and
interaction with extracellular matrix proteins (27). Taken
altogether, one might thus speculate that extravasated monocytes
themselves, in a positive feedback loop, trigger further alveolar
monocyte influx by MCP-1 synthesis. Monocytes and macrophages may not,
however, be the only cells responsible for the regulation of the
alveolar space MCP-1 response in acute lung injury. Epithelial cells
have been shown to secrete MCP-1 constitutively (2,
23) and in response to the macrophage-derived
early-response cytokines TNF- and interleukin-1
(34), and they showed a polar secretion of this chemokine
into the apical compartment for initiating or maintaining a chemotactic
gradient (29).
In conclusion, evidence is presented that the early expansion of the alveolar mononuclear phagocyte population observed in patients with ARDS is mainly due to a rapid influx of monocytes from the vascular compartment. Upregulation of MCP-1 synthesis and its secretion into the alveolar space are suggested to be centrally involved in this process. These events were found to be significantly correlated with the severity of respiratory failure. Further studies are encouraged to elucidate the mechanisms responsible for MCP-1 regulation and the on- and off-switching of the monocyte recruitment response in more detail.
| |
ACKNOWLEDGEMENTS |
|---|
We thank M. Lohmeyer, R. Maus, and G. Wahler for excellent technical assistance and Dr. R. L. Snipes for proofreading the manuscript.
| |
FOOTNOTES |
|---|
This work was supported by the Deutsche Forschungsgemeinschaft, Klinische Forschergruppe "Respiratorische Insuffizienz" (Justus-Liebig-University, Giessen, Germany).
Address for reprint requests and other correspondence and present address of S. Rosseau: Charité-Humboldt Univ. Berlin, Dept. of Internal Medicine and Infectious Diseases, Campus Virchow, Augustenburger Platz 1, 13353 Berlin, Germany (E-mail: simone.rosseau{at}charite.de).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Received 17 August 1999; accepted in final form 2 February 2000.
| |
REFERENCES |
|---|
|
TOP
ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
|
|---|
1.
Barnstable, CJ,
Bodmer WF,
Brown G,
Galfre G,
Milstein C,
Williams AF,
and
Ziegler A.
Production of monoclonal antibodies to group A erythrocytes, HLA and other human cell surface antigens
new tools for genetic analysis.
Cell
14:
9-13,
1978[Web of Science][Medline].
2.
Becker, S,
Quay J,
Koren HS,
and
Haskill JS.
Constitutive and stimulated MCP-1, GRO, , and 
expression in human airway epithelium and bronchoalveolar macrophages.
Am J Physiol Lung Cell Mol Physiol
266:
L278-L286,
1994
3.
Bhardwaj, RS,
Zotz C,
Zwadlo-Klarwasser G,
Roth J,
Goebler M,
Mahnke K,
Falk M,
Meinardus-Hager G,
and
Sorg C.
The calcium-binding proteins MRP8 and MRP14 form a membrane associated heterodimer in a subset of monocytes/macrophages present in acute but absent in chronic inflammatory lesions.
Eur J Immunol
22:
1891-1897,
1992[Web of Science][Medline].
4.
Biondi, A,
Rossing TH,
Bennett J,
and
Todd RF, III.
Surface membrane heterogeneity among human mononuclear phagocytes.
J Immunol
132:
1237-1243,
1984[Abstract].
5.
Bitterman, PB,
Saltzman LE,
Adelberg S,
Ferrans VJ,
and
Crystal RG.
Alveolar macrophage replication: one mechanism for the expansion of the mononuclear phagocyte population in the chronically inflamed lung.
J Clin Invest
74:
460-469,
1984.
6.
Bost, TW,
Riches DWH,
Schumacher B,
Carre PC,
Khan TZ,
Martinez JAB,
and
Newman LS.
Alveolar macrophages from patients with beryllium disease and sarcoidosis express increased levels of mRNA for TNF- and IL-6 but not IL-1.
Am J Respir Cell Mol Biol
10:
506-513,
1994[Abstract].
7.
Brieland, JK,
Jones ML,
Clarke SJ,
Baker JB,
Warren JS,
and
Fantone JC.
Effect of acute inflammatory lung injury on the expression of monocyte chemoattractant protein-1 (MCP-1) in rat pulmonary alveolar macrophages.
Am J Respir Cell Mol Biol
7:
134-139,
1992.
8.
Brieland, JK,
Jones ML,
Flory CM,
Miller GR,
Warren JS,
Phan SH,
and
Fantone JC.
Expression of monocyte chemoattractant protein-1 (MCP-1) by rat alveolar macrophages during chronic lung injury.
Am J Respir Cell Mol Biol
9:
300-305,
1993.
9.
Car, BD,
Meloni F,
Luisetti M,
Semenzato G,
Gialdroni-Grassi G,
and
Walz A.
Elevated IL-8 and MCP-1 in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis and pulmonary sarcoidosis.
Am J Respir Crit Care Med
149:
655-659,
1994[Abstract].
10.
Chollet-Martin, S,
Montravers P,
Elbim C,
Desmonts JM,
Fagon JY,
and
Gougerot-Pocidalo MA.
High levels of interleukin-8 in the blood and alveolar spaces of patients with pneumonia and adult respiratory distress syndrome.
Infect Immun
61:
4553-4559,
1993
11.
Chomczynski, P,
and
Sacchi N.
Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction.
Anal Biochem
162:
156-159,
1987[Web of Science][Medline].
12.
Cordell, J,
Falini B,
Erber WN,
Gosh A,
Abdulaziz Z,
Macdonald S,
Pulford K,
Stein H,
and
Mason DY.
Immunoenzymatic labelling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP complexes).
J Histochem Cytochem
32:
219-229,
1984[Abstract].
13.
Doherty, DE,
Haslett C,
Tonnesen MG,
and
Henson PM.
Human monocyte adherence: a primary effect of chemotactic factors on the monocyte to stimulate adherence to human endothelium.
J Immunol
138:
1762-1771,
1987[Abstract].
14.
Donelly, SC,
Strieter RM,
Kunkel SL,
Walz A,
Robertson CR,
Carter DC,
Grant IS,
Pollok AJ,
and
Haslett C.
Interleukin-8 and development of adult respiratory distress syndrome in at-risk patient groups.
Lancet
341:
643-647,
1993[Web of Science][Medline].
15.
Feinberg, AP,
and
Vogelstein B.
A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity.
Anal Biochem
132:
6-13,
1983[Web of Science][Medline].
16.
Goodman, RB,
Strieter RM,
Martin DP,
Steinberg KP,
Milberg JA,
Maunder RJ,
Kunkel SL,
Walz A,
Hudson LD,
and
Martin TR.
Inflammatory cytokines in patients with persistence of the acute respiratory distress syndrome.
Am J Respir Crit Care Med
154:
602-611,
1996[Abstract].
17.
Gunn, MD,
Nelken NA,
Liao X,
and
Williams LT.
Monocyte chemoattractant protein-1 is sufficient for the chemotaxis of monocytes and lymphocytes in transgenic mice but requires an additional stimulus for inflammatory activation.
J Immunol
158:
376-383,
1997[Abstract].
18.
Hance, AJ,
Douches S,
Winchester RJ,
Ferrans VJ,
and
Crystal RG.
Characterization of mononuclear phagocyte subpopulations in the human lung by using monoclonal antibodies: changes in alveolar macrophage phenotype associated with pulmonary sarcoidosis.
J Immunol
134:
284-292,
1985[Abstract].
19.
Hasday, JD,
Dubin W,
Mongovin S,
Goldblum SE,
Swoveland P,
Leturcq DJ,
Moriarty AM,
Bleecker ER,
and
Martin TR.
Bronchoalveolar macrophage CD14 expression: shift between membrane-associated and soluble pools.
Am J Physiol Lung Cell Mol Physiol
272:
L925-L933,
1997
20.
Hoogsteden, HC,
van Dongen JJM,
van Hal PTW,
Delahaye M,
Hop W,
and
Hilvering C.
Phenotype of blood monocytes and alveolar macrophages in interstitial lung disease.
Chest
95:
574-577,
1989
21.
Hufnagle, GB,
Strieter RM,
Standiford TJ,
McDonald RA,
Burdick MD,
Kunkel SL,
and
Toews GB.
The role of monocyte chemoattractant protein-1 (MCP-1) in the recruitment of monocytes and CD4+ T cells during a pulmonary Cryptococcus neoformans infection.
J Immunol
155:
4790-4797,
1995[Abstract].
22.
Kiemle-Kallee, J,
Kreipe H,
Radzun HJ,
Parwaresch MR,
Auerswald U,
Magnussen H,
and
Barth J.
Alveolar macrophages in idiopathic pulmonary fibrosis display a more monocyte-like phenotype and an increased release of free oxygen radicals.
Eur Respir J
41:
400-408,
1991.
23.
Koyama, S,
Sato E,
Nomura H,
Kubo K,
Nagal S,
and
Izumi T.
Type II pneumocytes release chemoattractant activity for monocytes constitutively.
Am J Physiol Lung Cell Mol Physiol
272:
L830-L837,
1997
24.
Leonard, EJ,
and
Yoshimura T.
Human monocyte chemoattractant protein-1 (MCP-1).
Immunol Today
11:
97-101,
1990[Web of Science][Medline].
25.
Lohmeyer, J,
Friedrich J,
Rosseau S,
Pralle H,
and
Seeger W.
Multiparameter flow cytometric analysis of inflammatory cells contained in bronchoalveolar lavage fluid.
J Immunol Methods
172:
59-70,
1994[Web of Science][Medline].
26.
Lohmeyer, J,
Rieber EP,
Feucht H,
Johnson J,
Hadam M,
and
Riethmueller G.
A subset of natural killer cells isolated and characterized by monoclonal antibodies.
Eur J Immunol
11:
997-1003,
1981[Web of Science][Medline].
27.
Lukacs, NW,
Strieter RM,
Elner V,
Evanoff HL,
Burdick MD,
and
Kunkel SL.
Production of chemokines, interleukin-8 and monocyte chemoattractant protein-1, during monocyte: endothelial cell interactions.
Blood
86:
2767-2773,
1995
28.
Maus, U,
Rosseau S,
Seeger W,
and
Lohmeyer J.
Separation of human alveolar macrophages by flow cytometry.
Am J Physiol Lung Cell Mol Physiol
272:
L566-L571,
1997
29.
Paine, R, III,
Rolfe MW,
Standiford TJ,
Burdick MD,
Rollins BJ,
and
Strieter RM.
MCP-1 expression by rat type II alveolar epithelial cells in primary culture.
J Immunol
150:
4561-4570,
1993[Abstract].
30.
Passlick, B,
Fleiger D,
and
Ziegler-Heitbrock HWL
Identification and characterization of a novel monocyte subpopulation in human peripheral blood.
Blood
74:
2527-2534,
1989
31.
Schuette, H,
Lohmeyer J,
Rosseau S,
Ziegler S,
Siebert C,
Kielisch H,
Pralle H,
Grimminger F,
Morr H,
and
Seeger W.
Bronchoalveolar and systemic cytokine profiles in patients with ARDS, severe pneumonia and cardiogenic lung edema.
Eur Respir J
9:
1858-1867,
1996[Abstract].
32.
Sorg, R,
Enczmann J,
Sorg U,
Heermeier K,
Schneider EM,
and
Wernet P.
Rapid and sensitive mRNA phenotyping for interleukins (IL-1 to IL-6) and colony-stimulating factors (G-CSF, M-CSF, and GM-CSF) by reverse transcription and subsequent polymerase chain reaction.
Exp Hematol
19:
882-887,
1991[Web of Science][Medline].
33.
Sozzani, S,
Molino M,
Locati M,
Luini W,
Cerletti C,
Vecchi A,
and
Mantovani A.
Receptor-activated calcium influx in human monocytes exposed to monocyte chemotactic protein-1 and related cytokines.
J Immunol
150:
1544-1553,
1993[Abstract].
34.
Standiford, TJ,
Kunkel SL,
Phan SH,
Rollins BJ,
and
Strieter RM.
Alveolar macrophage-derived cytokines induce monocyte chemoattractant protein-1 expression from human pulmonary type II-like epithelial cells.
J Biol Chem
266:
9912-9918,
1991
35.
Steinberg, KP,
Milberg JA,
Martin TR,
Maunder RJ,
Cockrill BA,
and
Hudson LD.
Evolution of bronchoalveolar cell populations in the adult respiratory distress syndrome.
Am J Respir Crit Care Med
150:
113-122,
1994[Abstract].
36.
Stríz, I,
Wang YM,
Svarcová I,
Trnka L,
Sorg C,
and
Costabel U.
The phenotype of alveolar macrophages and its correlation with immune cells in bronchoalveolar lavage.
Eur Respir J
6:
1287-1294,
1993[Abstract].
37.
Stríz, I,
Zheng L,
Wang YM,
Pokorná H,
Bauer PC,
and
Costabel U.
Soluble CD14 is increased in bronchoalveolar lavage of active sarcoidosis and correlates with alveolar macrophage membrane-bound CD14.
Am J Respir Crit Care Med
151:
544-547,
1995[Abstract].
38.
Sugiyama, Y,
Kasahara T,
Mukaida N,
Matsushima K,
and
Kitamura S.
Chemokines in bronchoalveolar lavage fluid in summer-type hypersensitivity pneumonitis.
Eur Respir J
8:
1084-1090,
1995[Abstract].
39.
Takahashi, M,
Masuyama J,
Ikeda U,
Kasahara T,
Kitagawa S,
Takahashi Y,
Shimada K,
and
Kano S.
Induction of monocyte chemoattractant protein-1 synthesis in human monocytes during transendothelial migration in vitro.
Circ Res
76:
750-757,
1995
40.
Vaddi, K,
and
Newton RC.
Regulation of monocyte integrin expression by beta-family chemokines.
J Immunol
153:
4721-4732,
1994[Abstract].
41.
Warren, JS,
Jones ML,
and
Flory CM.
Analysis of monocyte chemoattractant protein 1-mediated lung injury using rat lung organ cultures.
Am J Pathol
143:
894-906,
1993[Abstract].
42.
Wassermann, K,
Subklewe M,
Pothoff G,
Banik N,
and
Frederick-Schell E.
Expression of surface markers on alveolar macrophages from symptomatic patients with HIV infection as detected by flow cytometry.
Chest
105:
1324-1334,
1994
43.
Zheng, L,
Teschler H,
Guzman J,
Hubner K,
Striz I,
and
Costabel U.
Alveolar macrophage TNF- release and BAL cell phenotypes in sarcoidosis.
Am J Respir Crit Care Med
152:
1061-1066,
1995[Abstract].
44.
Ziegler-Heitbrock, HWL,
and
Ulevitch RL.
CD14: cell surface receptor and differentiation marker.
Immunol Today
14:
121-125,
1993[Web of Science][Medline].
45.
Zwadlo, G,
Brocker EB,
von Bassewitz DB,
Feige U,
and
Sorg C.
A monoclonal antibody to a differentiation antigen present on mature human macrophages and absent from monocytes.
J Immunol
134:
1487-1491,
1985[Abstract].
46.
Zwadlo, G,
Voegeli R,
Schulze-Osthoff K,
and
Sorg C.
A monoclonal antibody to a novel differentiation antigen on human macrophages associated with down-regulatory phase of the inflammatory process.
Exp Cell Biol
55:
295-304,
1987[Web of Science][Medline].
This article has been cited by other articles:
|
|
 |
|
  A. K. A. Wright, S. Rao, S. Range, C. Eder, T. P. J. Hofer, M. Frankenberger, L. Kobzik, C. Brightling, J. Grigg, and L. Ziegler-Heitbrock Pivotal Advance: Expansion of small sputum macrophages in CF: failure to express MARCO and mannose receptors J. Leukoc. Biol., September 1, 2009; 86(3): 479 - 489. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Hodge, G. Hodge, J. Ahern, H. Jersmann, M. Holmes, and P. N. Reynolds Smoking Alters Alveolar Macrophage Recognition and Phagocytic Ability: Implications in Chronic Obstructive Pulmonary Disease Am. J. Respir. Cell Mol. Biol., December 1, 2007; 37(6): 748 - 755. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. von Wulffen, M. Steinmueller, S. Herold, L. M. Marsh, P. Bulau, W. Seeger, T. Welte, J. Lohmeyer, and U. A. Maus Lung Dendritic Cells Elicited by Fms-like Tyrosin 3-Kinase Ligand Amplify the Lung Inflammatory Response to Lipopolysaccharide Am. J. Respir. Crit. Care Med., November 1, 2007; 176(9): 892 - 901. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. A. Maus, S. Janzen, G. Wall, M. Srivastava, T. S. Blackwell, J. W. Christman, W. Seeger, T. Welte, and J. Lohmeyer Resident Alveolar Macrophages Are Replaced by Recruited Monocytes in Response to Endotoxin-Induced Lung Inflammation Am. J. Respir. Cell Mol. Biol., August 1, 2006; 35(2): 227 - 235. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. M. Meyer, L. D. Dwyer-Nield, G. Hurteau, R. L. Keith, Y. Ouyang, B. M. Freed, L. R. Kisley, M. W. Geraci, J. V. Bonventre, R. A. Nemenoff, et al. Attenuation of the pulmonary inflammatory response following butylated hydroxytoluene treatment of cytosolic phospholipase A2 null mice Am J Physiol Lung Cell Mol Physiol, June 1, 2006; 290(6): L1260 - L1266. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-T. Yen, F. Liao, C.-H. Hsiao, C.-L. Kao, Y.-C. Chen, and B. A. Wu-Hsieh Modeling the Early Events of Severe Acute Respiratory Syndrome Coronavirus Infection In Vitro J. Virol., March 15, 2006; 80(6): 2684 - 2693. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Matthay and G. A. Zimmerman Acute Lung Injury and the Acute Respiratory Distress Syndrome: Four Decades of Inquiry into Pathogenesis and Rational Management Am. J. Respir. Cell Mol. Biol., October 1, 2005; 33(4): 319 - 327. [Full Text] [PDF]
|
|
|
|
|
|
K. Raghavendran, B. A. Davidson, B. A. Mullan, A. D. Hutson, T. A. Russo, P. A. Manderscheid, J. A. Woytash, B. A. Holm, R. H. Notter, and P. R Knight Acid and particulate-induced aspiration lung injury in mice: importance of MCP-1 Am J Physiol Lung Cell Mol Physiol, July 1, 2005; 289(1): L134 - L143. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Rosseau, K. Wiechmann, S. Moderer, J. Selhorst, K. Mayer, M. Krull, A. Hocke, H. Slevogt, W. Seeger, N. Suttorp, et al. Moraxella catarrhalis-Infected Alveolar Epithelium Induced Monocyte Recruitment and Oxidative Burst Am. J. Respir. Cell Mol. Biol., February 1, 2005; 32(2): 157 - 166. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. A. Maus, S. Wellmann, C. Hampl, W. A. Kuziel, M. Srivastava, M. Mack, M. B. Everhart, T. S. Blackwell, J. W. Christman, D. Schlondorff, et al. CCR2-positive monocytes recruited to inflamed lungs downregulate local CCL2 chemokine levels Am J Physiol Lung Cell Mol Physiol, February 1, 2005; 288(2): L350 - L358. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Goto, H. Ishii, J. C. Hogg, C.-H. Shih, K. Yatera, R. Vincent, and S. F. van Eeden Particulate Matter Air Pollution Stimulates Monocyte Release from the Bone Marrow Am. J. Respir. Crit. Care Med., October 15, 2004; 170(8): 891 - 897. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. C. Hildebrandt, K. M. Olkiewicz, L. A. Corrion, Y. Chang, S. G. Clouthier, C. Liu, and K. R. Cooke Donor-derived TNF-{alpha} regulates pulmonary chemokine expression and the development of idiopathic pneumonia syndrome after allogeneic bone marrow transplantation Blood, July 15, 2004; 104(2): 586 - 593. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Wright, L. A. Ginger, N. Kosila, N. D. Elkins, B. Essary, J. L. McManaman, and J. E. Repine Mononuclear Phagocyte Xanthine Oxidoreductase Contributes to Cytokine-Induced Acute Lung Injury Am. J. Respir. Cell Mol. Biol., April 1, 2004; 30(4): 479 - 490. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. C. Hildebrandt, U. A. Duffner, K. M. Olkiewicz, L. A. Corrion, N. E. Willmarth, D. L. Williams, S. G. Clouthier, C. M. Hogaboam, P. R. Reddy, B. B. Moore, et al. A critical role for CCR2/MCP-1 interactions in the development of idiopathic pneumonia syndrome after allogeneic bone marrow transplantation Blood, March 15, 2004; 103(6): 2417 - 2426. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. E. Lekka, S. Liokatis, C. Nathanail, V. Galani, and G. Nakos The Impact of Intravenous Fat Emulsion Administration in Acute Lung Injury Am. J. Respir. Crit. Care Med., March 1, 2004; 169(5): 638 - 644. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. G. Vazquez de Lara, T. M. Umstead, S. E. Davis, and D. S. Phelps Surfactant protein A increases matrix metalloproteinase-9 production by THP-1 cells Am J Physiol Lung Cell Mol Physiol, October 1, 2003; 285(4): L899 - L906. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Mokart, B. P. Guery, R. Bouabdallah, C. Martin, J.-L. Blache, C. Arnoulet, and J.-L. Mege Deactivation of Alveolar Macrophages in Septic Neutropenic ARDS Chest, August 1, 2003; 124(2): 644 - 652. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 U. A. Maus, K. Waelsch, W. A. Kuziel, T. Delbeck, M. Mack, T. S. Blackwell, J. W. Christman, D. Schlondorff, W. Seeger, and J. Lohmeyer Monocytes Are Potent Facilitators of Alveolar Neutrophil Emigration During Lung Inflammation: Role of the CCL2-CCR2 Axis J. Immunol., March 15, 2003; 170(6): 3273 - 3278. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. S. Bhalla and R. J. Folz Idiopathic Pneumonia Syndrome after Syngeneic Bone Marrow Transplant in Mice Am. J. Respir. Crit. Care Med., December 15, 2002; 166(12): 1579 - 1589. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Hamacher, R. Lucas, H. R. Lijnen, S. Buschke, Y. Dunant, A. Wendel, G. E. Grau, P. M. Suter, and B. Ricou Tumor Necrosis Factor-{alpha} and Angiostatin Are Mediators of Endothelial Cytotoxicity in Bronchoalveolar Lavages of Patients with Acute Respiratory Distress Syndrome Am. J. Respir. Crit. Care Med., September 1, 2002; 166(5): 651 - 656. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Yu, X. Zheng, H. Witschi, and K. E. Pinkerton The Role of Interleukin-6 in Pulmonary Inflammation and Injury Induced by Exposure to Environmental Air Pollutants Toxicol. Sci., August 1, 2002; 68(2): 488 - 497. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Maus, K. von Grote, W. A. Kuziel, M. Mack, E. J. Miller, J. Cihak, M. Stangassinger, R. Maus, D. Schlondorff, W. Seeger, et al. The Role of CC Chemokine Receptor 2 in Alveolar Monocyte and Neutrophil Immigration in Intact Mice Am. J. Respir. Crit. Care Med., August 1, 2002; 166(3): 268 - 273. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Presneill, T. Harris, A. G. Stewart, J. F. Cade, and J. W. Wilson A Randomized Phase II Trial of Granulocyte-Macrophage Colony-Stimulating Factor Therapy in Severe Sepsis with Respiratory Dysfunction Am. J. Respir. Crit. Care Med., July 15, 2002; 166(2): 138 - 143. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. MAUS, J. HUWE, L. ERMERT, M. ERMERT, W. SEEGER, and J. LOHMEYER Molecular Pathways of Monocyte Emigration into the Alveolar Air Space of Intact Mice Am. J. Respir. Crit. Care Med., January 1, 2002; 165(1): 95 - 100. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. L. Laskin, B. Weinberger, and J. D. Laskin Functional heterogeneity in liver and lung macrophages J. Leukoc. Biol., August 1, 2001; 70(2): 163 - 170. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. MAUS, J. HUWE, R. MAUS, W. SEEGER, and J. LOHMEYER Alveolar JE/MCP-1 and Endotoxin Synergize to Provoke Lung Cytokine Upregulation, Sequential Neutrophil and Monocyte Influx, and Vascular Leakage in Mice Am. J. Respir. Crit. Care Med., August 1, 2001; 164(3): 406 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. A. Maus, M. A. Koay, T. Delbeck, M. Mack, M. Ermert, L. Ermert, T. S. Blackwell, J. W. Christman, D. Schlondorff, W. Seeger, et al. Role of resident alveolar macrophages in leukocyte traffic into the alveolar air space of intact mice Am J Physiol Lung Cell Mol Physiol, June 1, 2002; 282(6): L1245 - L1252. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
