IL-12 p80 is an innate epithelial cell effector that mediates chronic allograft dysfunction.
BACKGROUND
Bronchiolitis obliterans syndrome is the leading cause of chronic lung allograft dysfunction. We have demonstrated that respiratory viral infection is a bronchiolitis obliterans syndrome risk factor and virus-dependent injury induces expression of innate airway epithelial genes belonging to the interleukin (IL)-12 family. Thus, we hypothesized that epithelial cell IL-12 family members could mediate lung allograft dysfunction.


OBJECTIVE
We used mouse and human allograft specimens to evaluate the role of epithelial cell IL-12 family members in allograft dysfunction associated with and without viral infection.


METHODS
Murine and human IL-12 family members were characterized and manipulated in allografts and then correlated with epithelial cell injury, immune cell accumulation, and collagen deposition.


RESULTS
In a mouse model of lung transplantation, concurrent viral infection and allogeneic transplantation increased epithelial injury and this was followed by exaggerated accumulation of macrophages and collagen deposition. This virus-driven allograft dysfunction was associated with an epithelial innate response manifested by a synergistic increase in the production of the macrophage chemoattractant IL-12 p80 (p80), but not IL-12 or IL-23. Blockade or overexpression of donor epithelial p80 resulted in a corresponding abrogation or enhancement of macrophage accumulation and allograft dysfunction. We extended these findings to human recipients with viral infection and transplant bronchitis and again observed excessive epithelial p80 expression that correlated with increased macrophage accumulation.


CONCLUSIONS
These experiments support a role for an enhanced epithelial innate response as a central process in allograft dysfunction and identify the macrophage chemoattractant p80 as an innate epithelial effector of disease progression.
Mikols
Cassandra L
CL
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Yan
Le
L
Norris
Jin Y
JY
Russell
Tonya D
TD
Khalifah
Anthony P
AP
Hachem
Ramsey R
RR
Chakinala
Murali M
MM
Yusen
Roger D
RD
Castro
Mario
M
Kuo
Elbert
E
Patterson
G Alexander
GA
Mohanakumar
Thalachallour
T
Trulock
Elbert P
EP
Walter
Michael J
MJ
D000818:Animals; D001989:Bronchiolitis Obliterans / Q000276:immunology; D002908:Chronic Disease; D018450:Disease Progression; D004791:Enzyme Inhibitors / Q000378:metabolism; D006084:Graft Rejection / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology*; D018664:Interleukin-12 / Q000502:physiology*; D008168:Lung / Q000276:immunology / Q000821:virology; D016040:Lung Transplantation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D021122:Protein Subunits / Q000502:physiology*; D014598:Uteroglobin / Q000378:metabolism
D004791:Enzyme Inhibitors; C513581:IL-12 p80, mouse; D021122:Protein Subunits; C556389:SCGB1A1 protein, human; C556390:Scgb1a1 protein, mouse; D018664:Interleukin-12; D014598:Uteroglobin