CD4 and systemic lupus erythematosus: Despite our findings that STAT4 does not overtly affect Spt-AFC and -GC and various CD4+ effector T cell responses, we investigated whether STAT4 may play a role in the hallmark kidneymanifestations of SLE-prone mice, particularly given the previous observations showing acceleration of kidney disease in one model (35) and amelioration in the other SLE model deficient in STAT4 (34).