Seronegative MSM at high risk of HIV-1 acquisition show an immune quiescent profile with a normal immune response against common antigens.

Human immunodeficiency virus (HIV) infection still represents a major public health problem worldwide, and its vaccine remains elusive. The study of HIV-exposed seronegative individuals (HESN) brings important information about the natural resistance to HIV, allows a better understanding of the infection, and opens doors for new preventive and therapeutic strategies. Among HESN groups, there are some men who have sex with men (MSM) with high-risk sexual behaviors, who represent an adequate cohort for HESN study because of their major HIV exposure without infection. This study aimed to compare the immunological profile of Colombian seronegative MSM with different risk sexual behaviors. This study included 60 MSM at high-risk (n = 16) and low-risk (n = 44) of HIV-1 acquisition. No sex worker nor homozygous delta 32 mutation subjects were included. All participants were negative for anti-HIV-1/2 antibodies and HIV-1 proviral DNA. A higher frequency of sexual partners in the last 3 months before the study participation (median, 30 vs. 2), lifetime sexual partners (median, 1,708 vs. 26), and unprotected anal intercourse (median 12.5 vs. 2) was determined in high-risk MSM than low-risk MSM. High-risk MSM also showed a quiescent profile of T cells and natural killer (NK) cells, with a significantly lower percentage of CD4+CD38+, CD4+HLADR-CD38+, CD4+Ki67+ T cells, and NKG2D+ NK cells (CD3-CD16+CD56+), a significantly higher percentage of CD4+HLADR-CD38-, and a tendency to show a higher percentage of CD8+HLADR+CD38- T cells than the low-risk group. Likewise, they showed higher mRNA levels of Serpin A1 from PBMCs. The results suggest that this MSM cohort could be HESN individuals and their resistance would be explained by a quiescent profile of T cells and NK cells and an increased Serpin A1 expression. Further study on MSM at high risk of exposure to HIV-1 is necessary to better understand the natural resistance to HIV.

Evaluación de la coloración de Albert para la identificación de Corynebacterium spp. en flujo vaginal / Evaluation of Albert´s staining technique for Corynebacterium spp. in vaginal swabs

Introducción: la detección del género Corynebacterium en flujo vaginal representa un reto para el estudio de su posible papel patogénico en el tracto genital femenino. La coloración de Gram es la técnica recomendada para la detección de corinebacterias en muestras clínicas; no obstante, algunas características biológicas de estas bacterias dificultan la identificación por medio de esta. Objetivo: evaluar el desempeño de la coloración de Albert para la identificación de Corynebacterium spp. en muestras de flujo vaginal. Materiales y métodos: se evaluó la tinción de Albert como prueba diagnóstica para la identificación de Corynebacterium spp. en 451 flujos vaginales en comparación de la coloración de Gram. Se calculó la sensibilidad, la especificidad, los valores predictivos, las razones de verosimilitud y el índice J de Youden con el software Epidat 3.1. Resultados: la coloración de Albert presentó sensibilidad y especificidad de 61,5% y 74,6%, respectivamente, valor predictivo positivo de 78,3%, valor predictivo negativo de 56,5%, razón de verosimilitud positiva de 2,4 y negativa de 0,5 y un Índice de Youden de 0,4. Conclusiones: la tinción de Albert no mostró un mejor rendimiento que la coloración de Gram en la identificación del género Corynebacterium en muestras de flujo vaginal. Por lo tanto, se recomienda el uso en conjunto de las coloraciones de Gram y Albert para la identificación de corinebacterias en flujo vaginal. (AU)

Introduction: The detection of Corynebacterium genus in vaginal discharge represents a challenge for the study of its possible pathogenic role in the female genital tract. Gram's stain is recommended for corynebacteria detection in clinical samples, however, some biological characteristics of these bacteria difficult their identification by this technique. Objetive: to evaluate Albert's stain performans to identify Corynebacterium spp. in vaginal discharge. Materials and methods: Albert's stain was evaluated as a diagnostic test for the identification of Corynebacterium spp. in 451 vaginal swabs in comparison to Gram's stain. Sensitivity, specificity, predictive values, likelihood ratio, as well as Youden's J index were calculated using Epidat software 3.1 version. Results: Albert's stain had a sensitivity and specificity of 61.5% and 74.6%, respectively, positive predictive value of 78.3 %, negative predictive value of 56.5 %, positive likelihood ratio of 2.4 and negative likelihood ratio of 0.5, as well as Youden index of 0.4. Conclusions: Albert's stain did not show better performance than Gram's stain for identification of corynebacteria in vaginal swabs. Thereforeit is recommended the concomitant use of the Gram and Albert stains for the identification of corynebacteria in vaginal discharge. (AU)