Search for genetic markers of predisposition to psoriasis and psoriatic arthritis

Abstract

Psoriasis (PS) and psoriatic arthritis (PsA) are interrelated diseases that occur in approximately 30% of patients and are characterized by the presence of a systemic inflammatory reaction that occurs as a result of a violation of the functional state of the immune system. With the advent of new technologies, several new pro-inflammatory cytokines, such as IL-23, IL-31, and IL-33, which play an important role in the pathogenesis of the psoriatic process, have been discovered and characterized. It was determined that single nucleotide polymorphisms (SNPs) in the promoter regions of the IL23, IL31 and IL33 genes play an important role in controlling the expression of relevant cytokines involved in the immunopathogenesis of psoriatic disease. The purpose of the study: to analyze the distribution of genotypes and allelic variants of polymorphisms of the IL23A (rs2066808), IL23R (rs2201841), IL31 (rs7977932) and IL33 (rs7044343), in order to search for genetic markers of predisposition to psoriasis and psoriatic arthritis. Materials and methods. The genotyping of the patients was conducted: psoriasis (PS, n = 77), median age 31.0 years (27.0-43.0), psoriatic arthritis (PsA, n = 99), median age 49.0 years (39.0-56.0) and practically healthy residents of Krasnoyarsk (n = 103), a median age of 32.0 years (24.0-38.0). DNA was isolated from whole venous blood using a standard sorbent kit. Genotyping of single nucleotide polymorphisms IL23A (rs2066808), IL23R (rs2201841), IL31 (rs7977932), IL33 (rs7044343) was carried out using real-time PCR using specific oligonucleotide primers and fluorescentlylabeled probes. Results and discussion. The frequencies of allelic variants of the studied cytokine genes in the control group obtained during the study correspond to their distribution in Caucasoid populations – the alleles IL23A * T, IL23R * T, IL31 * C, IL33 * C prevail. When comparing the distribution frequency of allelic variants of the IL23A, IL23R, IL31, IL33 genes, we did not obtain statistically significant differences between patients and the control group. Conclusions. Despite the fact that when comparing the distribution frequency of allelic variants of the IL23A, IL23R, IL31, IL33 genes, we did not obtain statistically significant differences between the patients and the control group, there are results worthy of attention. So, in patients with PS, the frequency of the C * IL23A allelic variant (rs2066808) is lower than in the population sample, which may indicate its specific role in relation to the development of the disease. All this dictates the need to continue research with the assessment of other SNPs and increase the sample of patients in search of potential genetic markers of psoriatic disease.

Keywords

• psoriatic arthritis
• cytokines
• il23
• il31
• il33
• gene polymorphism