CD19 and common variable immunodeficiency: These changes included an increase in the percentage of CD19+ PD-1+ (3.28-fold), CD8+ CTLA-4+ (1.36-fold), CD4+ CD200+ (1.61-fold), and CD86+ in all lymphocyte subpopulations tested (1.16-fold for CD4+, 1.33-fold for CD8+, and 1.57-fold for CD19+, respectively), and CD200 (1.61-fold for CD4+, 1.39-fold for CD8+, and 1.57-fold for CD19+, respectively) (42-fold for CD19+) and CD200R (2.85-fold for CD4+, 1.46-fold for CD8+, and 1.16-fold for CD19+, respectively) in CLL vs. CVID patients (Supplementary Table S3).