MDDCs induced by SLE serum containing highly elevated levels of IL-10 exhibited a reduced ability to stimulate allogenic T cell proliferation compared with those induced by normal serum alone at all DC:T cell ratios tested, and addition of anti-IL-10 neutralizing antibodies into the SLE serum reversed these changes at DC:T cell ratios of 1:10, 1:20 and 1:50 (Fig. 7A). This evidence concerns the gene IL10 and systemic lupus erythematosus.