CD4 and type 1 diabetes mellitus: Although we detected a few cells with this activated Th1 phenotype in circulation from every donor, there was a very substantial expansion in the SLE patient (2.5% of memory CD4+ T cells compared to 0.3% and 0.1% in the T1D patient and healthy donor, respectively; Fig. 7d), suggesting that it could represent a pathogenic CD4+ T cell subset associated with systemic autoimmunity in this patient.