Análise do Polimorfismo -607 C/A (RS1946518) do gene IL-18 em pacientes com artrite reumatóide do estado de Pernambuco

Abstract

Rheumatoid arthritis (RA) is a systemic autoimmune disease that affects about 1% of the world's population, affecting both sexes. However, there is a higher incidence of cases for women than men. There is still no clarity regarding the etiology of the disease, but it knows whether it includes genetic and environmental factors. An IL-18 is a proinflammatory cytokine and its high level is qualified with a severity of inflammatory, chronic and destructive diseases. Thus, this study aimed to analyze the -607 C / A polymorphism of the IL-18 gene in patients diagnosed with RA and its relationship with disease severity. A survey was conducted with 114 patients, 111 women and 3 men resident in the city of Recife-PE. Blood collection was performed and then DNA extraction was performed, followed by amplification by conventional polymerase chain reaction (PCRc). After PCR, the samples were run on blue Green loading dye (LGC) stained 2% (w / v) agarose gel and the result visualized in UV light. Statistical analyzes were performed using univariate analysis, with significance level p <0.05, applying the one-way ANOVA test. For genotypic frequency, samples were submitted to Chi-square test, considering significant p <0.05. Patients with AA genotype show a significantly higher mean for Clinical Disease Activity Index (CDAI) (25.15 ± 11.06) when compared to the other CC and CA genotypes (16.32 ± 9.26 and 20, 49 ± 9.76) respectively. These results suggest that IL-18 may be related to increased CDAI when the patient has the AA genotype. Disease Activity Score 28 (DAS 28) (p = 0.096) and Health Assessment Questionnaire (HAQ) values (p = 0.823) were not significant in relation to AA, CC and CA genotypes, showing no association of polymorphism with these activity indices, suggesting that this polymorphism is not associated with the patient's disability. The rheumatoid factor (RF) analysis showed no statistically significant results (p = 0.879) and also the erosion analysis results showed no statistical significance (p = 0.529), suggesting that IL-18 polymorphism (-607 C / A (RS1946518)) is not associated with erosion and rheumatoid factor. Thus, we can say that IL-18 (-607 C / A (RS1946518)) may be associated with disease activity when related to increased CDAI in patients with AA genotype. However, further studies are needed to better understand the association of polymorphism of other IL-18 gene regions in the development of RA.