Association of the p75NTR Ser205Leu Polymorphism with Asymptomatic HTLV-1 Infection.

Genetic variations in components of the immune response seem to be an important factor that contributes to the manifestation of symptoms of some diseases related to HTLV-1 infection. Nerve growth factor (NGF) and the p75 neurotrophin receptor (p75NTR) are related to the maintenance of neurons and the activation of the immune response. In this study, we evaluated the association of the NGF -198C/T, NGF Ala35Val, and p75NTR Ser205Leu polymorphisms with HTLV-1 infection and plasma cytokine levels in 166 samples from individuals infected with HTLV-1 (59 symptomatic and 107 asymptomatic). The genotyping and quantification of the proviral load were performed by real-time PCR, and cytokine levels were measured by ELISA. The NGF -198C/T and NGF Ala35Val polymorphisms were not associated with HTLV-1 infection. The frequency of the Ser/Leu genotype of p75NTR Ser205Leu was more frequent in the control group (p = 0.0385), and the Ser/Leu genotype and allele Leu were more frequent among the asymptomatic (p < 0.05), especially with respect to the HTLV-1-associated myelopathy (HAM) group (p < 0.05). The symptomatic showed a higher proviral load and higher TNF-α and IL-10 levels (p < 0.05). Asymptomatic carriers of the Ser/Leu genotype (p = 0.0797) had lower levels of proviral load and higher levels of TNF-α (p = 0.0507). Based on the results obtained, we conclude that the p75NTR Ser205Leu polymorphism may be associated with reduced susceptibility to HTLV-1 infection, a lower risk of developing symptoms, including HAM, and better infection control.

Hepatitis C virus genotypes and associated risk factors in the state of Pará, Northern Brazil.

BACKGROUND: Despite the emergence of more effective therapies, hepatitis C virus (HCV) infection remains a serious public health problem at the global level. Currently, this virus is classified into seven genotypes and 67 subgenotypes, which in turn are distributed heterogeneously in Brazil and worldwide. Studies have shown that this genetic divergence results in differences in the progression of chronic disease associated with HCV infection and its treatment. OBJECTIVE: The aim of this study was to report the frequency of HCV genotypes in the state of Pará, Northern Brazil, and to assess the association between genotype and different clinical and laboratory characteristics, as well as risk factors for infection. METHOD: Data from 85 medical records of untreated patients who had chronic hepatitis C infection were analyzed; the patients were evaluated at two hospitals in Belem, Pará, Brazil. RESULTS: Circulation of genotypes 1 and 3 was detected, with a higher prevalence of genotype 1 (75.3%) than genotype 3 (24.7%). In addition, there was a predominance of subgenotype 1b (60.34%) compared to 1a (20.69%) and 3a (18.97%). Reuse of needles and/or glass syringes was significantly associated with infection by HCV genotype 1 than genotype 3; however, the small number of patients infected with genotype 3 may have biased the results. No associations between genotype and the evaluated clinical and laboratory characteristics were observed. CONCLUSION: This study reinforces the differences in the distribution of HCV genotypes in Brazil and showed no association between HCV genotype and progression of chronic hepatitis C in the studied group.