In vivo role of IL-10 and IL-12 during development of Sjögren's syndrome in MRL/lpr mice.

Expression of local cytokine genes including interleukin 10 (IL-10) and IL-12 was analyzed in the salivary gland tissues of MRL/lpr mice with Sjögren's syndrome. We demonstrate a significant role of IL-10 and IL-12 in vivo during development of Sjögren's syndrome in MRL/lpr mice. IL-10 mRNA expression was detected before the onset of disease and was upregulated during the course of autoimmune sialadenitis by RT-PCR. A predominant level of expression of IL-12 mRNA was also detected earlier in the proinflammatory stage of autoimmune sialadenities. Moreover, MHC class II (I-Ak) mRNA was detected before the onset of inflammatory lesions until older ages in the salivary glands of MRL/lpr mice. These results suggest that endogenous IL-10 and IL-12 may play important roles on immune-mediated destruction of the salivary glands during development of organ-specific autoimmunity in MRL/lpr mice.