Polimorfismo -174g>C do gene de Interleucina-6 da tuberculose pulmonar

Abstract

The aim of this study was to investigate the profile of IL-6 production in patients with active pulmonary tuberculosis and to evaluate the functional role of polymorphism -174G>C in the systemic production of this cytokine. A total of 63 patients and 99 controls were studied. Among them 38 patients [25(65.8%) males] and 63 controls [51(81%) males] were studied for the IL-6 dosage. Moreover, 42 patients [25(60%) males] and 79 controls [62(78.5%) males] were studied for the -174G>C polymorphism. Patients were selected from Dona Libânia Center; Messejana Hospital, Maracanau Hospital and Dr. Cesar Cals General Hospital. The control group was selected from HEMOCE. An ELISA test was performed to measure IL-6 in peripheral blood. The genomic DNA was extracted from peripheral blood and IL-6 polymorphism was studied by polymerase chain reaction using sequence-specific primers. The IL-6 dosage showed an increase in patients with tuberculosis in relation to controls (An increase in IL6 dosage was found in patients with tuberculosis in relation to controls) (median= 4.3 pg/mL vs 0.5 pg/mL, p<0.001), but no difference was observed in drug-sensitive patients in comparison to drug-resistant ones. The genotype distribution showed no difference between patients and controls. In relation to the functional study, the IL-6 levels pointed out a significant increase in patients presenting GG genotype (median=4.1 pg/mL, range 0.5-12.0 pg/mL), in relation to GC and CC careers; these two latter genotypes presented similar IL-6 production as in healthy individuals with median=0.6 pg/mL, range 0.0-2.8 pg/mL, corroborating statistical significance with p=0.04. The relevance of this study is to show in vivo the functional role of IL-6 polymorphism in active pulmonary tuberculosis. Conclusion, the GG genotype in patients with pulmonary tuberculosis determines an increase in IL-6 systemic production.