It would be really interesting in the future to analyze further the IL-10 locus and its possible interactions with other loci coding for other molecules involved in B cell maturation and final differentiation to plasma cells, like genes coding for IL-10 receptor chains or the gene recently described as associated with IgAD and common variable immunodeficiency, TACI [31,32]. Here, TNFRSF13B is linked to common variable immunodeficiency.