Abstract
PURPOSE: The immunomodulatory effects of thalidomide (TM) and dexamethasone (DX) on immune cells and their co-stimulatory, co-inhibitory molecules in vitro and in vivo have been previously reported. The current study investigated the effects of TM and the combinatorial treatment with DX on immune cells using a murine cardiac allograft transplantation model. MATERIALS AND METHODS: Intraabdominal transplant of cardiac allografts from BALB/c (H-2(d)) donors to C57BL/6 (H-2(b)) recipients was performed. After transplantation, mice were injected daily with TM or DX or a combination of both TM and DX (TM/DX) by intraperitoneal route until the time of graft loss. CD4(+) T cell subsets and CD11c(+) cells in the peripheral blood mononuclear cells and spleen were examined and quantified with flow cytometry. Serum IL-6 levels were measured by enzyme-linked immunosorbent assay on day 7. RESULTS: The mean graft survivals were 6.86 days in the untreated group, and 10.0 days in the TM/DX group (p<0.001). The TM/DX treatment affected the CD4(+) T cell subsets without suppressing the total CD4(+) T cell population. The CD4(+)FOXP3(+)/CD4(+)CD44(hi) T cell ratio increased. Increase in cell counts and median fluorescence intensity on CD11c(+)CD85k(+) with TM/DX were observed. The inhibition of pro-inflammatory cytokine interleukin-6 was also observed. CONCLUSION: These outcomes suggest the immunomodulating effect of the TM/DX combinatorial treatment. In conclusion, TM/DX combination may be a promising immunomodulatory approach for preventing allograft rejection and improving graft survival by inducing tolerance in transplantation.