In line with this hypothesis, more in depth analysis of the immature and naive compartments of pre-GC B-cells showed that while <10% of CVID patients had lower counts in blood of the less differentiated CD5- CD38++ CD21het CD24 ++ immature B-lymphocytes, more than a third of the cases showed reduced counts of the more differentiated CD5+ CD38het CD21+ CD24+ immature B-cells. Here, CD38 is linked to common variable immunodeficiency.