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.

[The biological characterization of HIV-1 isolated in patients with a rapid clinical evolution]. / Caracterización biológica de aislamientos de VIH-1 en pacientes con una evolución clínica rápida.

The biological characteristics of 11 HIV-1 strains isolated from patients with a fast clinical evolution to AIDS were studied. The viral isolates were classified according to their replication kinetics and cell tropism. Taking into account these criteria, it was observed that 8 of the isolated strains (72.7%) were of rapid high growth (RH) or slow low 3 (SL3) with preferential tropism to the lymphocytic stock, as it corresponds to AIDS patients. 3 (27.3%) had characteristics of slow low 1 (SL1). The cytopathogenicity of the strains was studied in the MT4 cellular line, and it was observed that most of them (72.7%) were syncytium-inducing strains (SI), which allowed to prove the in vivo and in vitro relation of the biological properties. It was not so in 3 of the cultures (27.3%) that behaved as non-syncytium inducers.

[The serological diagnosis of HIV-1 in samples of dried blood on filter paper by the HIV-1 DAVIH Dot system]. / Diagnóstico serológico del VIH-1 en muestras de sangre seca en papel de filtro por el sistema DAVIH Dot VIH-1.

Dried blood specimens spotted on filter paper were evaluated by the HIV-1 DAVIH Dot system from DAVIH Laboratories (Havana, Cuba). The samples used, 103 positive and 105 negative, were previously confirmed by DAVIH Blot from DAVIH Laboratories. In order to use the dried blood on filter paper some modifications were made to the original procedure regarding the times of incubation of the samples and conjugate, and the agitation in both stages. Relative sensitivity and specificity of 100 and 99.05%, respectively, were attained.

[Confirmation of the presence in Cuba of human T-cell lymphotropic virus type I using the polymerase chain reaction]. / Confirmación de la presencia en Cuba del virus linfotrópico tipo I de las células T humanas mediante la reacción en cadena de la polimerasa.

The first cases diagnoses in Cuba as HTLV-I/II seropositives (human T lymphotropic virus) were studied by polymerase chain reaction aimed at differentiating the type of virus causing the infection. 3 kits of primer oligonucleotides were used and the amplification products were detected by hybridization with specific oligoprobes. 100% of the cases were HTLV-I positives. No HTLV-II positivity was found. It was confirmed the presence in Cuba of this retrovirus, even though the seroprevalence is low if it is taken into consideration that the Caribbean is an endemic zone for HTLV-1.

[The detection of antibodies against HIV-1 24-kd protein. A clinico-serological correlation]. / Detección de anticuerpos contra la proteína de 24 kd del VIH-1. correlación clínico serológica.

The presence of antibodies against the HIV protein of 24 kd was studies by the parallel use of the DAVIH BLOT western blot and of the DAVIH AC P24 ELISA in serum samples from 176 patients at different HIV-1 infection stages. The results were correlated with the clinical classification of the patient at the moment of taking the sample and with the further evolution during 6 months. 57% of the patients with opportunistic minor infections and 96% of AIDS patients had low antibodies titres. Dead patients showed no reactivity or presented very low titres in samples taken before dying. Different titrations were observed in serum groups with an apparently uniform reactivity in the western blot. The results show and adequate clinical and serological correlation. Therefore, the DAVIH AC P24 ELISA could be useful in the clinical follow-up of HIV-1 infected persons.