Influence of IL-28B serum level and gene polymorphism in a sample of Iraqi patients with ankylosing spondylitis

Ankylosing spondylitis (AS) represents one kind of advanced arthritis formed via inflammatory stimuli long-term in the spin‘s joints. Interleukin (IL)-29 (interferon- lambda1(IFN- λ1)), interleukin (IL)-28A (interferon- lambda 2 (IFN- λ2)) and interleukin (IL)-28B (interferon- lambda 3(IFN-λ3)) are three interferon lambda (IFN- λs) molecules that have recently been identified as new members of the IFN family. IL-28B expression in ankylosing spondylitis (AS) is not well understood. 150 male healthy controls ((HC) and 160 males with AS as patients group participated in this study. Serum level and gene polymorphism were assessed using an enzyme-linked immunosorbent assay and Sanger sequencing for IL-28B, respectively. The results showed significantly lower serum IL-28B concentrations in the AS groups in comparison to the HC groups (both p values equal to 0.003). There was a large difference in IL-28B genotype and allele frequency between the two individuals. IL-28B heterozygote genotype CT of rs12979860 SNP exhibits a substantial correlation with AS (P = 0.008). While the genotypes of rs12980275 SNP were not shown any significant correlation with AS. The findings suggest that serum concentration of IL-28B is a potential diagnostic biomarker in patients with AS, and that the heterozygote CT of rs12979860 SNP serves as a potential risk factor for the onset of AS in the Iraqi population.