TLR9 and systemic lupus erythematosus: While the overall TR B cell frequencies in SLE patients correlated positively with TLR7 expression (R = 0.339, p = 0.0088); we found no correlation between TR B cell frequencies and the expression of other TLRs, including TLR9 (Supplemental Figures 4A,B), suggesting the effect on TR B cells is specific to TLR7.