Genotypic resistance mutations to antiretroviral drugs in HIV-1 B and non-B subtypes from Cuba.

OBJECTIVES: To determine the prevalence of drug resistance and to analyze the subtyping in HIV-1 samples from Cuba. METHODS: From an estimated total number of 1,950 HIV-1-infected persons in Cuba, a sample of 103 patients were studied, 76 of whom had received drug treatment for HIV and 27 who had not. The RNA plasma viral load was measured, and automated sequencing was used to assess resistance mutations to reverse transcriptase inhibitors (RTIs) and to protease inhibitors (PIs). Subtyping in the V3 region was performed using heteroduplex mobility assay (HMA). In order to corroborate the HMA results, sequencing of env (C2-V3-C3) was done with one-third of the samples in each of the subtype groups detected by HMA. RESULTS: Out of the 103 samples, 81 of them (78.6%) were classified as subtype B, 19 (18.5%) as subtype A, and 3 (2.9%) as subtype C. The prevalence of resistance mutations was 26.2% to RTIs, none to PIs alone, and 3.9% to both categories of drugs. The prevalence of resistance to nucleoside RTIs (NRTIs) was 27.6% in treated patients and 7.4% in the untreated patients, and for nonnucleoside RTIs (NNRTIs) it was 5.3% and 0%, respectively. Among treated patients a low frequency (2.6%) of dual resistance to zidovudine (ZDV) plus lamivudine (3TC) and abacavir (ABC) was detected, and multidrug resistance to NRTIs was not found. In relation to PIs together with RTIs, the prevalence of resistance was 5.3% for treated patients and 0% for untreated patients. CONCLUSIONS: Even though Cuba is generally considered an area where subtype B is dominant, we detected a high proportion of non-B subtype viruses. The low prevalence of resistance mutations to RTIs and PIs reflects the delay in introducing these drugs to Cuba. Multidrug resistance to RTIs was not found, so, as of now, the use of these drugs continues to be an option for Cuban patients.

[Inactivation of BVDV (experimental model for hepatitis C) using low pH and heat treatment in intravenous human immunoglobulins]. / Inactivación del VDVB (modelo experimental del virus de la hepatitis C) por pH bajo y tratamiento por calor en inmunoglobulinas humanas endovenosas.

PURPOSE: To measure the capability of heat (60 degrees C for 10 hr) and low pH to inactivate BVDV (a model of HCV) in human intravenous immunoglobulins. MATERIALS AND METHODS: The study was carried out on three batches of immunoglobulins produced by the Cohn method and contaminated with a known amount of BVDV. These mixtures, with and without 33% sorbitol, were submitted to heat treatment at 60 degrees C for 10 hours. The same immunoglobulin batches were manufactured at pH 4.25 and 4.5 and stored at 4 degrees C and 4 degrees C and 21 degrees C for 28 days. Samples of the two experiments were taken at the beginning and the end. The viral infectiousness was calculated by the standard microtiration method in 96-well plates, using the CPE, and the reduction factor was measured for each experiment. RESULTS: Complete viral inactivation was achieved with the heat treatment after 4 hours, and the 33% sorbitol decreased the formation of aggregates. Treatment by pH 4.5, at 21 degrees C for 28 days, decreased the viral load by approximately 2 log; no viral inactivation was achieved in samples stored at 4 degrees C. CONCLUSION: Heat is an effective method for inactivating HCV in final batches of human intravenous immunoglobulins when 33% sorbitol is added. The use of low pH at 21 degrees C as a method of viral inactivation must be evaluated case by case, since, according to the present results, it only achieved a 2 log inactivation.