Genotipagem da gp41 do Vírus da Imunodeficiência Humana tipo 1 (HIV-1) em indivíduos respondedores e não respondedores ao inibidor de fusão T20

• Ano de defesa: 2009
• Autor(a) principal: Azevedo, Rafael Gonçalves de [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Gp41; Mutations; Primary resistance; T20; HIV-1; Mutações; Resistência primária
• Link de acesso: https://repositorio.unifesp.br/handle/11600/9675

Introduction: the failure to HAART becomes important to development of new drugs that target different steps of the life cycle of HIV-1. The Enfuvirtide (T20) is a synthetic peptide that mimics the HR2 region of gp41 of HIV-1, preventing its fusion and entry into the host cell. The presence of primary resistance mutations to T20 can lead to lack of sustained virologic response (SVR) in people in the HAART failure. Objectives: to genotype the gp41 of HIV-1 subjects considered responders and nonresponders to T20; verify the presence of primary resistance mutations could influence the SVR, SVR status correlate with aspects of viral, immunological and tropism. Methodology: genomic DNA from baseline (before treatment), 6 and 12 months after treatment with T20, was purified using QIAamp DNA Mini kit (Qiagen ®, Valencia, California, USA). All patients received optimal therapy more T20 at the beginning. 506 bp referring to the HR1 and HR2 regions of gp41 were amplified by PCR nested. PCR nested the V3 region to study viral tropism amplified 654 bp. The PCR was purified using Montage ® PCR Centrifugal Filter Devises (Millipore ®). The PCRs of purified V3 and gp41 regions were sequenced in ABI Prism 3130 Genetic Analyzer (Applied Biosystems, CA, USA) with commercial kit BigDye ® Terminator Cycle Sequencing version 3.1 (Applied Biossystems, Foster City. California, USA). Initiators of the second stage of PCR nested were used for sequencing. Results: seven patients had a higher response to T20 for 12 months, 4 for at least 6 months and two did not respond between 6 and 12 months. The average age was 44.92 ± 5.39, and 46.16% female and 53.84% male. Of the 13 patients analyzed, 12 belong to subtype B and 1 to F1. Eight patients had the coreceptor R5 and five the X4. There were no mutations at positions 36 to 45 of HR1 in 12 months. We acquired the N42S, which is responsible for decreased susceptibility to T20. From a total of 59 amino acids analyzed in HR1, we observed 18.64% of change and in HR2 region, 38.88%. In HR1 within 8 months or more compared to the baseline, we found no changes in positions 36 to 45. From a total of 59 amino acids analyzed, we observed 15.25% of change and in HR2, 36.11%. We checked the E137K without the presence of N43D, which caused resistance. We checked the S138T mutation as the primary persistence of 12 months without the N43D and the lack of response to treatment. On the count of CD4 + T cells, we found no statistical difference between the means of different groups (ANOVA - p = 0.1). The viral loads after 6 months were undetectable (<50 copies / mL) in 69.23% of patients. There was a decrease in viral load baseline to 6 months (p = 0.034) and for 6 months and 8 months or more. The use of the drug had significant interference when compared to baseline and 6 months (p = 0.004) and between baseline and 12 months (p = 0.022), but between 6 and 12 months the interference was not significant, showing that after 6 months it remains sustainable. Among the variables, responders and R5 genotype, there were high value of similarity (76.98). There was a grouping between the two samples of responders with X4 genotype with mutations 306, 311 and 320 which characterize it. Discussion: regarding tropism, 38.47% of the patients studied had correceptor X4 after a few years of infection and multiple HAART regimens. This result shows agreement with the literature, which describes an average rate of 50%. The N42S, observed in our study is associated with decreased drug susceptibility. However, only one patient did not respond to treatment, without increase of his immune. Conclusion: the tropism of HIV-1 in the majority of people who responded to the T20 is strongly associated with the R5, which causes rapid progression. The presence of S138T was sufficient for the lack of response to T20, but no association with N43D. It was clearly shown SVR and immune recovery with the T20, but that was not enough to remove these people from the risk of contracting opportunistic diseases. Our study showed the importance of starting the rescue when the count of CD4 + T cells are above 200 cells/mm3.