T and B-cell perturbations identify distinct differences in HIV-2 compared with HIV-1 induced immunodeficiency.

Background: For unknown reasons, HIV-2 is less pathogenic than HIV-1, and HIV-2-induced immunodeficiency may be different from that caused by HIV-1. Previous immunological studies have hinted at possible shifts in both T-cell and B-cell subsets, which we aimed to characterize further. Methods: From an HIV clinic in Guinea-Bissau, 63 HIV-2, 83 HIV-1, and 26 HIV-negative participants were included. All HIV-infected participants were ART-naive. The following cell subsets were analysed by flow cytometry; T cells (maturation and activation), regulatory T cells, and B cells (maturation and activation). Results: After standardizing for sex, age, and CD4(+) T-cell count HIV-2 had 0.938 log(10) copies/ml lower HIV RNA levels than the HIV-1-infected patients. Whereas T-cell maturation and regulatory T-cell profiles were similar between patients, HIV-2-infected patients had higher proportions of CD8(+)CD28(+) and lower proportions of CD8(+)PD-1+ T cells than HIV-1-infected patients. This finding was independent of HIV RNA levels. HIV-2 was also associated with a more preserved proportion of naive B cells. Conclusion: HIV-2 is characterized by lower viral load, and lower T-cell activation, which may account for the slower disease progression. Copyright (C) 2019 Wolters Kluwer Health, Inc. All rights reserved.