Numerous studies have demonstrated higher circulating levels of IL10 in SLE sera and spontaneous production of the cytokine by B cells and monocytes (Csiszár et al., 2000; Gröndal et al., 2000; Houssiau et al., 1995; Llorente et al., 1993; Park et al., 1998). This evidence concerns the gene IL10 and systemic lupus erythematosus.