Several of these differentially expressed genes in both the CVID cohort and the CVID twin, include relevant genes for B-cell immune response such as CCL22, CD70, ICAM1, LGALS9, CD72 or PTPRC. Inspection of the CVID Ib subcohort led us to identify additional dysregulated genes shared with the CVID twin. This evidence concerns the gene LGALS9 and common variable immunodeficiency.