Influencia de polimorfismos dos genes TNF e PTPN22 sobre a artrite reumatoide e a tuberculose no Amazonas, Brasil

Abstract

Rheumatoid Arthritis (RA) is a autoimmune disease that affects 1% of worldwide population and promotes polyarthritis and joint destruction with work disability. About 60% of the risk factors of RA are related to genetic characteristics of individuals. The functional polymorphisms of the TNF gene -308 G/A andPTPN22 1858 C/T were associated with RA in several studies.The aim of this study was to investigate the influence of the TNF 308 G/A polymorphism in the promoter region of the tumor necrosis factor- gene and PTPN22 1858 C/T on rheumatoid arthritisand tuberculosis patients from the Brazilian Amazon. A total of 545 individuals 205 healthy controls without arthritis and 132 individuals suffering from rheumatoid arthritis and 208 tuberculosis patients  were genotyped for these polymorphisms using a methodology based on PCR-RFLP. Rheumatoid factor, age more than 60 years old and more than 10 disease years, was found to be risk factors for systemic disease (p=0,0001). The frequency of the A allele (TNF2) in rheumatoid arthritis sufferers was not found to be significantly higher than in the controls (p=0.671; OR=1.16; confidence interval=0.59 – 2.25). However, using a logistic regression model when the patients were stratified according to whether the manifestations were preponderantly articular or systemic, there was a strong association between the TNF2 allele and the systemic disease (p=0.001; OR=4.75; confidence interval=1.82 – 12.40) as well as the use of anti-TNF immunotherapy (p=0.021; OR 2.93; confidence interval=1.15 –7.46). On the other hand, PTPN22 1858T allele was not associated with systemicdisease (p=0,071; OR=3,17; confidence interval=0.83 – 11.73), but we found association between this allele and biologic anti-TNF immunotherapy (p=0,021; OR=4.39; confidence interval=1.08 – 17.86). Moreover, there was found no association between PTPN22 15858 C/T and rheumatoid arthritis nor tuberculosis. These results suggest that the TNF2 allele is associated with the more serious forms of the disease in individuals from the Brazilian Amazon but not with a risk for developing RA.