Expression of both Th1 and Th2 cytokines correlates with the histological rejection of MHC-matched and MHC-mismatched foetal pancreas allografts in mice

Foetal mouse pancreatic islet grafts were used to investigate differences in the histological appearance and cytokine expression pattern during acute rejection of fully MHC-mismatched, and MHC-matched but minor histocompatibility-mismatched (mH) allografts. Grafts of foetal islet tissue from non-obese diabetic mice under the kidney capsule of non-immunosuppressed MHC and mH-disparate BALB/c mice were rejected by day 9, whereas the rejection of only mH-disparate C3H tissue into CBA mice occurred between 11 and 15 days. In both situations enhanced expression of transcripts for Th1 (IL-2, IFN-gamma, TNF-beta) and Th2 cytokines (IL-4, IL-6, IL-10) was demonstrable at the peak of infiltration of immune cells into the graft site, indicating a close association of these cytokines with graft destruction. Besides these kinetic differences no variation in the expression pattern of the tested cytokines could be demonstrated, indicating that the allograft response in either combination leads to enhanced expression of pro-inflammatory cytokines which could contribute to graft destruction.