In addition proportions of CD4+ CD25-Foxp3+ T cells showed a significant correlation with CD4+CD25+Foxp3+ (r = 0.7; P <0.0001) but not with CD4+CD25+Foxp3- (r = 0.17; P <0.32) in SLE patients (Additional file 1: Figure S1). Here, CD4 is linked to systemic lupus erythematosus.