This analysis showed that two populations are significantly increased in SLE patients compared to healthy and autoimmune diseases controls (Figure 5C): SM B cells co-expressing SLAMF1, SLAMF3, SLAMF5 and SLAMF6 (identified as SLESMB) and cTfh CD4+ T cells co-expressing SLAMF1, SLAMF3, SLAMF5 and SLAMF6 receptors (identified as SLEcTFH). Here, LY9 is linked to systemic lupus erythematosus.