CD38 and diabetes mellitus: In both area 4 (CD38hiCXCR3hi) and area 6 (CD38intCXCR3hi), CD38 expression was reduced in individuals with long-standing diabetes vs healthy donors (area 4: p < 0.05 in Study A, p < 0.005 in Study B; area 6: p < 0.05 in Study A, p < 0.05 in Study B; Fig. 4i, j), whereas in area 3 (CXCR3lo), CD38 expression was increased in newly diagnosed individuals vs healthy donors (p < 0.05 in Study A, p < 0.005 in Study B; Fig. 4h).