Interleukin-10 (IL-10) is an anti-inflammatory cytokine that has been shown
to alter HLA expression in some hemopoietic cells. In skin, the presenting
capacity of Langerhans' cells is reduced by IL-10, but little is known abo
ut the effect of IL-10 on keratinocytes. Using in vitro experiments, we hav
e shown that IL-10 augments the HLA-DR expression of keratinocytes in the p
resence of interferon gamma. The increase in HLA-DR expression increased th
e stimulation and proliferation of allogeneic peripheral blood mononuclear
cells, which in turn increased the in vitro rejection of allogeneic keratin
ocytes. Therefore exogenous application of IL-10 to cultured keratinocytes
augments the rejection by allogeneic peripheral blood mononuclear cells in
vitro conditions rather than having the suspected protective effect.