CD38 and type 1 diabetes mellitus: Children with a single diagnosis were characterized by a higher percentage of CD27−CD19+ (T1D: P = 0.047, C: P = 0.015, Fig. 1A) and CD39+ expressing naive B cells (T1D: P = 0.024, C: P = 0.008, Fig. 1B); but lower percentage of CD38+ expressing naive B cells (T1D: P = 0.042, C: P = 0.015, Fig. 1C) compared to children with double diagnosis.