Regarding mature naive B-cells, an increase in CD21-CD24- (6.1 vs 0.74 cells/μl, p<0.0001) and CD21- CD24++ (1.8 vs 0.4 cells/μl, p<0.0001) naive B cell counts was observed in CVID vs. HD, with a clear bimodal distribution (Figure 3B) due to the presence of a major subgroup of patients (73% and 94%, respectively) presenting a significant expansion of these two naive B-cell subsets, in association or not with low CD21+ CD24+ naïve B-cell counts, which were found to be reduced in only 21% of CVID patients (Figure 3B). Here, CR2 is linked to common variable immunodeficiency.