Introduction. The 90% of the cases of Common Variable Immunodeficiency (CVID) are sporadic. Multifactorial genetic background related to immune dysfunction have been hypothetized, being B cell ontology the hallmark, this is controlled by ligand-receptors unions, which is B cell activation factor (TNFSF13B/BAFF) and Transmembrane activator and CAML interactor (TNFRSF13B/TACI). Nevertheless, the functionality of BAFF-TACI depends on its genetic variants (SNVs) in their genes, respectively. For that, this study aimed to analyze the association of SNVs (rs9514828C>T, rs201543678G>A, rs1224141T>G and rs10508198G>C; rs8079130T>C, rs121908379GG>CC, rs4792800A>G and rs34557412A>G) in TNFSF13B and TNFRSF13B genes, respectively and its expression in a Western Mexican population with CVID.
Method. In this case-control study, were included 25 patients diagnosed with CVID and 112 healthy individuals (HI) with ascendance from Western Mexico (Jalisco, Nayarit, Colima and Michoacán). Genomic DNA and total RNA were obtained using Miller and Trizol methods, respectively. The SNVs were analyze by allelic discrimination (TaqMan® assays), and mRNA expression (SYBR® green RT-PCR) in the LightCycler® 96 Instrument-Roche.
Results. SNVs studied agreed Hardy-Weinberg Equilibrium, except for the rs121908379GG˃CC of TNFRSF13B identified as monomorphic without the presence of minor allele in the studied population. The rs9514828 (T and TT), rs1224141 (G and genotypes carrying it), rs10508198 (CC) and its haplotypes CGG, TTC and TGG (TNFSF13B) and rs34557412 (G and AG + GG) (TNFRSF13B) were identified as protector factors to CVID. None of the SNVs studied or haplotypes are related to clinical features in CVID patients. In other hand, the mRNA of TNFSF13B gene is overexpressed 15.29-fold, meanwhile is TNFRSF13B subexpressed-50 fold in CVID vs HI (p˂0.05). Minor allele CVID carriers of rs201543678, rs1224141 and rs10508198 in TNFSF13B showed higher mRNA levels compared to wild-type allele carriers (p˂0.05), without haplotypic/clinical features relationships.
Conclusions. Variants and mRNA expression of TNFSF13B and TNFRSF13B are associated to CVID in Western Mexican population.