Allogeneic splenocyte transfer and lipopolysaccharide inhalations induce differential T cell expansion and lung injury: a novel model of pulmonary graft-versus-host disease.
BACKGROUND
Pulmonary GVHD (pGVHD) is an important complication of hematopoietic cell transplant (HCT) and is thought to be a consequence of the HCT conditioning regimen, allogeneic donor cells, and posttransplant lung exposures. We have previously demonstrated that serial inhaled lipopolysaccharide (LPS) exposures potentiate the development of pGVHD after murine allogeneic HCT. In the current study we hypothesized that allogeneic lymphocytes and environmental exposures alone, in the absence of a pre-conditioning regimen, would cause features of pGVHD and would lead to a different T cell expansion pattern compared to syngeneic cells.


METHODS
Recipient Rag1-/- mice received a transfer of allogeneic (Allo) or syngeneic (Syn) spleen cells. After 1 week of immune reconstitution, mice received 5 daily inhaled LPS exposures and were sacrificed 72 hours after the last LPS exposure. Lung physiology, histology, and protein levels in bronchoalveolar lavage (BAL) were assessed. Lung cells were analyzed by flow cytometry.


RESULTS
Both Allo and Syn mice that undergo LPS exposures (AlloLPS and SynLPS) have prominent lymphocytic inflammation in their lungs, resembling pGVHD pathology, not seen in LPS-unexposed or non-transplanted controls. Compared to SynLPS, however, AlloLPS have significantly increased levels of BAL protein and enhancement of airway hyperreactivity, consistent with more severe lung injury. This injury in AlloLPS mice is associated with an increase in CD8 T cells and effector CD4 T cells, as well as a decrease in regulatory to effector CD4 T cell ratio. Additionally, cytokine analysis is consistent with a preferential Th1 differentiation and upregulation of pulmonary CCL5 and granzyme B.


CONCLUSIONS
Allogeneic lymphocyte transfer into lymphocyte-deficient mice, followed by LPS exposures, causes features of pGVHD and lung injury in the absence of a pre-conditioning HCT regimen. This lung disease associated with an expansion of allogeneic effector T cells provides a novel model to dissect mechanisms of pGVHD independent of conditioning.
Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America.
Tereza
T
Martinu
Department of General Surgery, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
Christine V
CV
Kinnier
School of medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America.
Jesse
J
Sun
Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America.
Francine L
FL
Kelly
Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America.
Margaret E
ME
Nelson
Respiratory Biology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America.
Stavros
S
Garantziotis
Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America.
W Michael
WM
Foster
Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America.
Scott M
SM
Palmer
D000280:Administration, Inhalation; D019264:Adoptive Transfer; D000818:Animals; D018946:Chemokine CCL5 / Q000378:metabolism; D004195:Disease Models, Animal; D006086:Graft vs Host Disease / Q000209:etiology / Q000473:pathology / Q000628:therapy; D053804:Granzymes / Q000378:metabolism; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000276:immunology*; D055370:Lung Injury / Q000209:etiology* / Q000473:pathology / Q000628:therapy*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D022423:Myeloid Cells / Q000276:immunology / Q000378:metabolism; D013154:Spleen / Q000166:cytology*; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D014184:Transplantation, Homologous
D018946:Chemokine CCL5; D008070:Lipopolysaccharides; D007371:Interferon-gamma; D053804:Granzymes