Correlation of sex and stage with CD38-expression levels in CD4⁺ and CD8⁺ T cells. CD38-expression levels were significantly different in CD8⁺ T cells from male (n = 39) compared with female patients (n = 25), whereas the opposite, higher expression of CD38 in peripheral CD8⁺ T cells from healthy age-matched females (n = 13) compared with males (n = 20) was observed (A). (B) It was also in the CD8⁺ T-cell subset where a stage-dependent increase in CD38-expression levels was observed in male B-CLL patients. (C) Distribution of naive, central memory (TCM), effector memory (TEM), or effector memory RA⁺ (TEMRA) cells within the CD4⁺ and CD8⁺ pool within the CD38⁺ T-cell compartment of male patients (n = 23). Data are presented in box-and-whisker format: the 25th and 75th percentile form the box, with the median marked as a line, the 10th and 90th percentiles as whiskers, and all observations <10th percentile and >90th percentile as circles.