HIV-1 drug resistance and second-line treatment in children randomized to switch at low versus higher RNA thresholds

BACKGROUND: The PENPACT-1 trial compared virologic thresholds to determine when to switch to second-line antiretroviral therapy (ART). Using PENPACT-1 data, we aimed to describe HIV-1 drug resistance accumulation on first-line ART by virologic threshold. METHODS: PENPACT-1 had a 2 × 2 factorial design, randomizing HIV-infected children to start protease inhibitor (PI) versus nonnucleoside reverse transcriptase inhibitor (NNRTI)-based ART, and switch at a 1000 copies/mL versus 30,000 copies/mL threshold. Switch criteria were not achieving the threshold by week 24, confirmed rebound above the threshold thereafter, or Center for Disease Control and Prevention stage C event. Resistance tests were performed on samples ≥1000 copies/mL before switch, resuppression, and at 4-years/trial end. RESULTS: Sixty-seven children started PI-based ART and were randomized to switch at 1000 copies/mL (PI-1000), 64 PIs and 30,000 copies/mL (PI-30,000), 67 NNRTIs and 1000 copies/mL (NNRTI-1000), and 65 NNRTI and 30,000 copies/mL (NNRTI-30,000). Ninety-four (36%) children reached the 1000 copies/mL switch criteria during 5-year follow-up. In 30,000 copies/mL threshold arms, median time from 1000 to 30,000 copies/mL switch criteria was 58 (PI) versus 80 (NNRTI) weeks (P = 0.81). In NNRTI-30,000, more nucleoside reverse transcriptase inhibitor (NRTI) resistance mutations accumulated than other groups. NNRTI mutations were selected before switching at 1000 copies/mL (23% NNRTI-1000, 27% NNRTI-30,000). Sixty-two children started abacavir + lamivudine, 166 lamivudine + zidovudine or stavudine, and 35 other NRTIs. The abacavir + lamivudine group acquired fewest NRTI mutations. Of 60 switched to second-line, 79% PI-1000, 63% PI-30,000, 64% NNRTI-1000, and 100% NNRTI-30,000 were <400 copies/mL 24 weeks later. CONCLUSIONS: Children on first-line NNRTI-based ART who were randomized to switch at a higher virologic threshold developed the most resistance, yet resuppressed on second-line. An abacavir + lamivudine NRTI combination seemed protective against development of NRTI resistance

O sistema complemento e a resposta imunológica ao HIV / The complement system and the immune response to HIV

Objetivo: O objetivo do presente artigo é descrever os principais mecanismos pelos quais o sistema complemento está envolvido na infecçäo pelo HIV. Métodos: Através de um levantamento bibliográfico sobre o tema, os autores discutem os estudos realizados para avaliar os distúrbios do sistema complemento em pacientes HIV positivos, tanto na faixa etária pediátrica como no adulto, em diversos estagios. Resultados: Verifica-se que o sistema complemento se encontra ativado pelas vias clássica e alternativa, sem correlaçäo com o estagio da doença. A ativaçäo da via clássica ocorre através da ligaçäo de C1q e gp41/gp120 do vírus, permitindo a infecçäo de células que näo expressam CD4, contribuindo para disseminaçäo da doença. Portanto, os dados de literatura sugerem que o sistema complemento näo é eficaz no controle da infecçäo pela HIV