MBL primary deficiency, believed to be the commonest human immunodeficiency (affecting 5–10% of the population) is associated with LXA/O and O/O genotypes (reviewed by Cedzyński et al. [5]) Furthermore, several polymorphisms located within the 3′-untranslated region (exon 4) were reported to influence MBL serum concentration (Ex4-710 A > G (rs2099902), Ex4-901 A > G (rs2120132), Ex4-1047 T > G (rs12254577), Ex4-1067 G > A (rs10824792), Ex4-1483 T > C (rs10082466)) [53]. This evidence concerns the gene MBL2 and immunodeficiency disease.