CD4 and systemic lupus erythematosus: Since subset-specific CD38 expression varied among both SLE patients and HC, we determined the coefficient of variation (CV) for CD38 expression levels in the leukocyte subsets identified in Figure 1A. Highest CV differences between SLE and HC were identified for CD8+ T cells (mean CV, HC, 61%; SLE, 131%), B cells (HC, 44%; SLE, 95%), eosinophils (HC, 41%; SLE 84%), CD4+ T cells (HC, 60%; SLE 94%), and mDC (HC, 35%; SLE, 68%).