Our microarray results show that several genes related to signal transduction (CCL2, CXCL9, EMR2, GPR56, RGS2, TGFBR2, RGFBR3, and TGM2 in the categories 'cell surface receptor linked signal transduction' (enrichment = 2.7-fold; p = 10-2.1; FDR = 0.09) and 'G-protein coupled receptor protein signaling pathway' (enrichment = 5.1-fold; p = 10-3.1; FDR = 0.04) are differentially expressed in the CVID patient. This evidence concerns the gene CXCL9 and common variable immunodeficiency.