RESUMEN
El genoma del VIH contiene nueve genes, tres de estos genes (gag, pol y env) codifican proteínas estructurales. Existen dos variantes principales de este virus, VIH-1 y VIH-2. El primero es el causante de la mayoría de las infecciones a nivel mundial, actualmente se han identificado nueve subtipos de VIH-1 y 58 formas recombinantes circulantes (FRC). En Centroamérica, el subtipo B del VIH-1 es el causante de la mayoría de los casos de VIH positivo; en Guatemala se ha reportado la presencia de subtipo B, de formas recombinantes BF1 y del subtipo C; sin embargo, actualmente no existen análisis filogenéticos que indiquen las variantes de este subtipo. Debido a lo anterior, el objetivo del estudio fue llevar a cabo la subtipificación de 400 secuencias de la región pol del VIH-1 obtenidas de 400 pacientes VIH-1 positivos, en una clínica de atención integral de Guatemala del 2010 al 2015. Para determinar los distintos subtipos de VIH-1 presentes en Guatemala se realizó la subtipificación de las secuencias obtenidas por la prueba de genotipo en formato FASTA, con la herramienta REGA HIV-1 Subtyping Tool Version 3.0. Con el fin de determinar la relación entre las variantes de VIH-1, se realizó un alineamiento de secuencias y árboles filogenéticos utilizando el método Neighbor Joining y Máxima Verosimilitud con 100 réplicas bootstrap, con el programa MEGA 7.0.21. Se determinó que el subtipo con mayor frecuencia de las secuencias analizadas es el subtipo B con un 71.5 %, seguido de la forma recombinante BD (16.75 %) y el subtipo B-like (7.75 %)
The HIV genome contains nine genes, three of these genes (gag, pol, and env) encode structural proteins. There are two main variants of this virus, HIV-1 and HIV-2. The first one (HIV-1) is the cause of most infections worldwide, of which nine subtypes and 58 circulating recombinant forms (CRF) have been identified. In Central America, subtype B of HIV-1 is the cause of the majority of HIV positive cases. In Guatemala, it has been reported the presence of subtype B, recombinant forms BF1 and subtype C. However, no phylogenetic analysis has been performed to indicate the variants of this subtype. The aim of the study was to subtype 400 sequences of the pol region of HIV-1, of samples that were obtained from a care clinic during the period 2010 to 2015. To determine the different subtypes of HIV-1 present in Guatemala, the subtyping of the sequences obtained by the genotype test, in FASTA format, was performed with REGA HIV-1 Subtyping Tool - Version 3.0. In order to determine the relationship between HIV-1 variants, an alignment of sequences and phylogenetic trees was performed using the Neighbor Union and Maximum Likelihood method with 100 bootstrap replicas, with the MEGA 7.0.21 program. It was determined that the subtypes with the highest prevalence of the studied sequences are the subtype B (71.5 %), recombinant BD (16.75 %), and subtype B-like (7.75 %)
RESUMEN
The purpose of the present study was to compare the sensitivity and specificity of V3 enzyme immunoassay (solid phase EIA and EIA inhibition) and restriction fragment length polymorphism (RFLP) with the DNA sequencing "gold standard" to identify the Brazilian HIV-1 variants of subtype B and B"-GWGR. Peripheral blood mononuclear cells were collected from 61 HIV-1-infected individuals attending a clinic in São Paulo. Proviral DNA was amplified and sequentially cleaved with the Fok I restriction enzyme. Plasma samples were submitted to a V3-loop biotinylated synthetic peptide EIA. Direct partial DNA sequencing of the env gene was performed on all samples. Based on EIA results, the sensitivity for detecting B-GPGR was 70 percent, compared to 64 percent for the Brazilian variant B"-GWGR while, the specificity of B-GPGR detection was 85 percent, compared to 88 percent for GWGR. The assessment of RFLP revealed 68 percent sensitivity and 94 percent specificity for the B-GPGR strain compared to 84 and 90 percent for the B"-GWGR variant. Moreover, direct DNA sequencing was able to detect different base sequences corresponding to amino acid sequences at the tip of the V3 loop in 22 patients. These results show a similar performance of V3 serology and RLFP in identifying the Brazilian variant GWGR. However, V3 peptide serology may give indeterminate results. Therefore, we suggest that V3 serology be used instead of DNA sequencing where resources are limited. Samples giving indeterminate results by V3 peptide serology should be analyzed by direct DNA sequencing to distinguish between B-GPGR and the Brazilian variant B"-GWGR.