Genetic polymorphism of interleukin-16 and its association with the clinical and radiographic severity in primary knee osteoarthritis patients

To investigate the association between IL and 16 genetic (rs4072111) single nucleotide polymorphism (SNP) and susceptibility to primary knee osteoarthritis (KOA) and to elaborate its connection with clinical and radiographic severity of KOA. 80 primary KOA patients and 35 matched healthy controls. IL-16 gene rs4072111 SNP was genotyped in KOA patients and control using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique and verified by direct DNA sequencing. Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to assess the clinical severity of KOA and Kellgren lawrence (K/L) radiographic grading was evaluated. The 80 KOA patients were 60 female and 20 male patients with mean of 55.8 ± 8.9 years (38–71 years), BMI 25.5 ± 1.8 (16.5–27) and disease duration 5.8 ± 4.3 years (1–20 years). The mean WOMAC index was 52.9 ± 17.9 and the K/L score was 2.49 ± 0.73. Patients carrying the wild (CC) genotype had a significantly higher WOMAC index compared those carrying the TT and CT genotypes (p = 0.0.046) also, KL sore had tendency to increase in patient carrying the wild (CC) compared to patients carrying the TT and CT genotypes (p = 0.08), However, no direct genetic association was detected between the SNP and KOA. On performing a regression with WOMAC as the dependant factor only the triglycerides (p = 0.001) and K/L (p < 0.0001) were independent risk factors. Il-16 gene (rs4072111) SNP might be associated with clinical severity of KOA. Furthermore, the SNP is not likely to be associated with KOA susceptibility in the Egyptian population.