104 research outputs found
Mononuclear Cells From Human Lung Parenchyma Support AntigenâInduced T Lymphocyte Proliferation
We have previously demonstrated that there is a subpopulation of loosely adherent pulmonary mononuclear cells that can be isolated from minced and enzymeâdigested lung tissue with a potent capacity to stimulate allogeneic T lymphocyte proliferation. We now demonstrate that these cells are also capable of stimulating an autologous mixed leukocyte reaction (AMLR) and presenting antigen to autologous T lymphocytes. These loosely adherent mononuclear cells (LAM) were more effective than either alveolar macrophages or monocytes as antigenâpresenting cells. Depletion of phagocytic or Fc receptorâpositive cells from the LAM population enhanced the stimulation of an reaction AMLR while preserving antigenâinduced T lymphocyte proliferation. These results indicate that there are nonphagocytic, Fc receptorânegative accessory cells in human lung parenchyma capable of activating resting T cells in an AMLR and supporting antigenâspecific T lymphocyte proliferation. The identity of these cells is uncertain, but the data strongly suggest that the cell is not a classical monocyteâderived macrophage. These antigenâpresenting cells may be critical in the initiation of immune responses within the lung.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141257/1/jlb0336.pd
Separation of Potent and Poorly Functional Human Lung Accessory Cells Based on Autofluorescence
Human alveolar macrophages obtained by bronchoalveolar lavage are usually poor accessory cells in in vitro lymphoprollferation assays. However, we recently described a subpopulation of pulmonary mononuclear cells, obtained from minced and enzymeâdigested lung, which were potent stimulators of allogeneic Tâlymphocyte proliferation. These cells were enriched in loosely adherent mononuclear cell (LAM) fractions, but further study of these accessory cells was hampered by the heterogeneous nature of LAM. It was observed that in the majority of lung tissue sections, most alveolar macrophages were autofluorescent, whereas most interstitial HLAâDR positive cells were not. Therefore autofluorescence was utilized to fractionate LAM in an attempt to remove alveolar macrophages and selectively purify interstitial accessory cells. LAM were separated by flow cytometry using forward and side scatter to exclude lymphocytes, and red autofluorescence to obtain brightly autofluorescent (A pos) and relatively nonautofluorescent (A neg) mononuclear cells. Although both populations contained over 80% HLAâDR positive cells, A pos cells were poor accessory cells, whereas A neg cells were extremely potent stimulators of a mixed leukocyte reaction at all stimulator ratios tested. When A pos cells were added to A neg cells, Tâcell proliferation was markedly suppressed in the majority of experiments. Morphologically, A pos cells appeared similar to classical alveolar macrophages with 95% of the cells being large and intensely nonspecific esterase positive. In contrast, the majority of A neg were smaller, Bâcell antigenânegative, nonspecific esterase negative, and had a distinctive morphology on Wrightâstained smears. We conclude that fractionation of LAM based on autofluorescence is a powerful tool to isolate and characterize lung mononuclear cells that act either as stimulators or as suppressors of immune responses in the lung.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141667/1/jlb0458.pd
Hydrogen peroxide is a diffusible paracrine signal for the induction of epithelial cell death by activated myofibroblasts
Cellâcell signaling roles for reactive oxygen species (ROS) generated in response to growth factors/cytokines in nonphagocytic cells are not well defined. In this study, we show that fibroblasts isolated from lungs of patients with idiopathic pulmonary fibrosis (IPF) generate extracellular hydrogen peroxide (H2O2) in response to the multifunctional cytokine, transforming growth factorâÎČ1 (TGFâÎČ1). In contrast, TGFâÎČ1 stimulation of small airway epithelial cells (SAECs) does not result in detectable levels of extracellular H2O2. IPF fibroblasts independently stimulated with TGFâÎČ1 induce loss of viability and death of overlying SAECs when cocultured in a compartmentalized Transwell system. These effects on SAECs are inhibited by the addition of catalase to the coculture system or by the selective enzymatic blockade of H2O2 production by IPF fibroblasts. IPF fibroblasts heterogeneously express αâsmooth muscle actin stress fibers, a marker of myofibroblast differentiation. Cellular localization of H2O2 by a fluorescentâlabeling strategy demonstrated that extracellular secretion of H2O2 is specific to the myofibroblast phenotype. Thus, myofibroblast secretion of H2O2 functions as a diffusible death signal for lung epithelial cells. This novel mechanism for intercellular ROS signaling may be important in physiological/pathophysiological processes characterized by regenerating epithelial cells and activated myofibroblasts.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154383/1/fsb2fj042882fje.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154383/2/fsb2fj042882fje-sup-0001.pd
Differential regulation by leukotrienes and calcium of FcĂÂł receptorĂą induced phagocytosis and Syk activation in dendritic cells versus macrophages
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141597/1/jlb1234.pd
Un vivo depletion of murine CD8 positive T cells impairs survival during infection with a highly virulent strain of Cryptococcus neoformans
Cell-mediated immunity plays an important but incompletely understood role in host defense against Cryptococcus neoformans . Because of their multiple capacities as cytokine-secreting cells, cytotoxic cells, and antigen-specific suppressor cells, CD8 positive T lymphocytes could potentially either enhance or impair host defense against C. neoformans . To determine whether CD8 T cells enhance or inhibit host defence during an infection with a highly virulent strain of C. neoformans , we examined the effect of in vivo CD8 cell depletion on suNival and on the number of organisms in mice infected by either the intratracheal or intravenous routes. Adequacy of depletion was confirmed both phenotypically and functionally. Regardless of the route of infection, we found that survival of mice depleted of CD8 T cells was significantly reduced compared to undepleted mice. Surprisingly, however, CD8 depletion did not alter organism burden measured by quantitative CFU assay in mice infected by either route. These data demonstrate that CD8 positive T cells participate in the immune response to a highly virulent strain of C. neoformans . By contrast to minimally virulent isolates that do not cause a life threatening infection, the immune response to a highly virulent isolate does not alter the burden of organisms, but does enhance host defense as it is necessary for the optimal survival of infected mice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43267/1/11046_2005_Article_BF01103969.pd
Course of FEV1 after Onset of Bronchiolitis Obliterans Syndrome in Lung Transplant Recipients
Rationale: Bronchiolitis obliterans syndrome (BOS), defined by loss
of lung function, develops in the majority of lung transplant recipients.
However, there is a paucity of information on the subsequent
course of lung function in these patients.
Objectives: To characterize the course of FEV1 over time after development
of BOS and to determine the predictors that influence the
rate of functional decline of FEV1.
Methods: FEV1% predicted (FEV1%pred) trajectories were studied
in 111 lung transplant recipients with BOS by multivariate, linear,
mixed-effects statistical models.
Measurements and Main Results: FEV1%pred varied over time after
BOS onset, with the steepest decline typically seen in the first 6
months (12% decline; p < 0.0001). Bilateral lung transplant recipients
had significantly higher FEV1%pred at BOS diagnosis (71 vs.
47%; p < 0.0001) and at 24 months after BOS onset (58 vs. 41%;
p = 0.0001). Female gender and pretransplant diagnosis of idiopathic
pulmonary fibrosis were associated with a steeper decline
in FEV1%pred in the first 6 months after BOS diagnosis (p = 0.02
and 0.04, respectively). A fall in FEV1 greater than 20% in the
6 months preceding BOS (termed ârapid onsetâ) was associated
with shorter time to BOS onset (p = 0.01), lower FEV1%pred at
BOS onset (p < 0.0001), steeper decline in the first 6 months (p =
0.03), and lower FEV1%pred at 2 years after onset (p = 0.0002).
Conclusions: Rapid onset of BOS, female gender, pretransplant diagnosis
of idiopathic pulmonary fibrosis, and single-lung transplantation
are associated with worse pulmonary function after BOS onset.Supported in part by National Institutes of Health grants K23 HL077719 (V.N.L.)
and K24 HL04212 (F.J.M.), and by a grant from the American Society of Transplantation/
Chest Foundation (V.N.L.).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91969/1/2007 AJRCCM Course of FEV1 after Onset of Bronchiolitis Obliterans Syndrome in Lung Transplant Recipients.pd
Prognostic Value of Bronchiolitis Obliterans Syndrome Stage 0-p in Single-Lung Transplant Recipients
Rationale: Early diagnosis of bronchiolitis obliterans syndrome (BOS)
is critical in understanding pathogenesis and devising therapeutic
trials. Although potential-BOS stage (BOS 0-p), encompassing early
changes in FEV1 and forced expiratory flow, midexpiratory phase
(FEF25â75%), has been proposed, there is a paucity of data validating
its utility in single-lung transplantation. Objective: The aim of this
study was to define the predictive ability of BOS 0-p in single-lung
transplantation. Methods: We retrospectively analyzed spirometric
data for 197 single-lung recipients. Sensitivity, specificity, and positive
predictive value of BOS 0-p were examined over time using
Kaplan-Meier methodology. Results: BOS 0-p FEV1 was associated
with higher sensitivity, specificity, and positive predictive value than
the FEF25â75% criterion over different time periods investigated. The
probability of testing positive for BOS 0-p FEV1 in patients with
BOS (sensitivity) was 71% at 2 years before the onset of BOS. The
probability of being free from development of BOS 0-p FEV1 in
patients free of BOS at follow-up (specificity) was 93% within the
last year. Of patients who met the BOS 0-p FEV1 criterion, 81%
developed BOS or died within 3 years. The specificity and positive
predictive value curves for the BOS 0-p FEV1 were significantly different
between patients with underlying restrictive versus obstructive
physiology (p = 0.05 and 0.01, respectively). Conclusion: The FEV1
criterion for BOS 0-p provides useful predictive information regarding
the risk of development of BOS or death in single-lung recipients.
The predictive value of this criterion is higher in patients with
underlying restriction and is superior to the FEF25â75% criterion.Supported in part by National Institutes of Health grants K23 HL077719 and
K24HL04212 and American Lung Association RG-1059-N.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91970/1/2005 AJRCCM - Prognostic Value of Bronchiolitis Obliterans Syndrome Stage 0-p in Single-Lung Transplant Recipients.pd
Mesenchymal stromal cells in bronchoalveolar lavage as predictors of bronchiolitis obliterans syndrome
Rationale: Bronchoalveolar lavage fluid (BAL) from human lung
allografts demonstrates the presence of a multipotentmesenchymal
stromal cell population. However, the clinical relevance of this novel
cellular component of BAL and its association with bronchiolitis
obliterans syndrome (BOS), a disease marked by progressive airflow
limitation secondary to fibrotic obliteration of the small airways,
remains to be determined.
Objectives: In this study we investigate the association of number of
mesenchymal stromal cells in BAL with development of BOS in
human lung transplant recipients.
Methods:Mesenchymal colony-forming units (CFUs)were quantitated
in a cohort of 405 BAL samples obtained from 162 lung transplant
recipients. Poisson generalized estimating equations were used to
determine the predictors of BAL mesenchymal CFU count.
Measurements and Main Results: Higher CFU counts were noted early
post-transplantation; time from transplant to BAL of greater than
3 months predicted 0.4-fold lower CFU counts (P = 0.0001). BOS
diagnosis less than or equal to 365 days before BAL was associated
with a 2.11-fold higher CFU count (P = 0.02). There were 2.62- and
2.70-fold higher CFU counts noted in the presence of histologic
diagnosis of bronchiolitis obliterans (P = 0.05) and organizing
pneumonia (0.0003), respectively. In BAL samples obtained from
BOS-free patients greater than 6 months post-transplantation (n =
173), higher mesenchymal CFU counts (>=10) significantly predicted
BOS onset in both univariate (hazard ratio, 5.61; 95%CI, 3.03â10.38;
P < 0.0001) andmultivariate (hazard ratio, 5.02; 95%CI, 2.40â10.51;
P < 0.0001) Cox regression analysis.
Conclusions: Measurement of mesenchymal CFUs in the BAL provides
predictive information regarding future BOS onset.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91951/1/2011 AJRCCM Mesenchymal stromal cells in bronchoalveolar lavage as predictors of bronchiolitis obliterans syndrome.pd
Co-evolution of TH1, TH2 and TH17 Responses During Repeated Pulmonary Exposure to Aspergillus fumigatus Conidia
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89973/1/white-coevolution_th1_th2.pd
Idiopathic pulmonary fibrosis: Prognostic value of changes in physiology and six minute hallwalk.
Rationale and Hypothesis: Idiopathic pulmonary fibrosis is a fatal
disease with a variable rate of progression. We hypothesized that
changes in distance walked and quantity of desaturation during a
six-minute-walk test (6MWT) would add prognostic information to
changes in FVC or diffusing capacity for carbon monoxide.
Methods: One hundred ninety-seven patients with idiopathic pulmonary
fibrosis were evaluated. Desaturation during the 6MWT was
associated with increased mortality even if a threshold of 88%
was not reached. Baseline walk distance predicted subsequent walk
distance but was not a reliable predictor of subsequent mortality
in multivariate survival models. The predictive ability of serial
changes in physiology varied when patients were stratified by the
presence/absence of desaturation 88% during a baseline 6MWT.
For patients with a baseline saturation 88% during a 6MWT,
the strongest observed predictor of mortality was serial change in
diffusing capacity for carbon monoxide. For patients with saturation
88% during their baseline walk test, serial decreases in FVC
and increases in desaturation area significantly predicted subsequent
mortality, whereas decreases in walk distance and in diffusing
capacity for carbon monoxide displayed less consistent statistical
evidence of increasing mortality in our patients.
Conclusion: These data highlight the importance of stratifying patients
by degree of desaturation during a 6MWT before attributing
prognostic value to serial changes in other physiologic variables.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91940/1/2006 AJRCCM Idiopathic pulmonary fibrosis - Prognostic value of changes in physiology and six minute hallwalk.pd
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