Impact of CD40 gene variants [(rs1883832) and (rs4810485)] on the risk of immune thrombocytopenic purpura in Egyptian paediatric patients: a case-control study

Background Immune thrombocytopenic purpura (ITP) pathogenesis is a complex multifactorial process; and the precise underlying mechanisms remain unclear. Several Cluster of differentiation 40 (CD40) gene variants were identified and proved to be risk factors for many autoimmune disorders. Unfortunately, limited data prove CD40 gene variants association, and ITP risk. Though investigated in adults, to our knowledge no previous studies explored its role in paediatrics. Thus, we aimed to assess 2 common CD40 gene variants (rs1883832 C/T, rs4810485 G/T) and their relation to ITP susceptibility and progression in Egyptian children. Methods Sixty ITP children and 60 age-sex matched healthy controls were genotyped for CD40 rs1883832C greater than T and rs4810485G greater than T, using real-time polymerase chain reaction (PCR). Results CD40 rs1883832 and rs4810485 were in perfect linkage disequilibrium, D' = 1.00 (95% CI: 0.94-1.00) and r2=1 for cases and controls. Genotype distribution did not differ between the study groups p 0.79. T allele occurrence was almost the same for ITP (31.7%) cases and controls (30%), P = 0.780. None of the gene variants nor the corresponding alleles carried a higher risk for ITP. Most (˜90%) of the patients carrying the mutant variant (TT) were females P = 0.048. Genotypes were not associated with significant differences regarding clinical, laboratory or treatment response. CG and TT haplotypes were identified; with nonsignificant differences between both groups (P = 0.780). Conclusion In Egyptian children, CD40 rs1883832 C/T and rs4810485 do not carry an increased risk for ITP. More future studies are required to verify this observation together with measuring the serum level of CD 40. Keywords: cluster of differentiation 40, immune thrombocytopenic purpura, polymorphism, real-time polymerase chain reaction, rs1883832, rs4810485