Effective combined antiretroviral therapy provides partial immune recovery to mycobacterial antigens in vertically infected, BCG-vaccinated youth living with HIV.

BACKGROUND: We assessed the cytokine response by PBMC of youth living with HIV (YLHIV) under combined antiretroviral therapy (cART) to Mycobacterium tuberculosis (Mtb) and Mycobacterium bovis (BCG) antigens. METHODS: PBMC from 20 Brazilian YLHIV under cART with long-term (≥1 year) virological control, and 20 healthy controls were cultured for 24-96 h under stimulation with BCG, Mtb lysates, ESAT-6 and SEB. We measured TNF-α, IFN-γ, IL-2, IL-4, IL-5, IL-10 and IL-17 in culture supernatants using a cytometric bead array. RESULTS: Controls had higher IFN-γ production at 24, 48, 72 and 96 h upon stimulation with BCG lysate, plateauing at 48 h (Median = 1991 vs. 733 pg/mL; p = 0.01), and after 48-72 h of stimulation with Mtb lysate, plateauing at 48 h (3838 vs. 2069 pg/mL; p = 0.049). YLHIV had higher TNF-α production at all time points upon stimulation with ESAT-6, with highest concentration at 36 h (388 vs. 145 pg/mL; p = 0.02). Within the YLHIV group, total CD4 T cell count and CD4/CD8 ratio were associated with IFN-γ response to Mtb lysate and ESAT-6, respectively. CONCLUSIONS: Even under long-term cART, YLHIV seem to have a suboptimal T-helper-1 response to mycobacterial antigens. This can be explained by early immunodeficiency in vertical infection, with lasting damage.

Preservation of cytotoxic granule production in response to mycobacterial antigens by T-lymphocytes from vertically HIV-infected Brazilian youth on effective combined antiretroviral therapy

ABSTRACT Background: HIV infection harms adaptive cellular immunity mechanisms. Long-term virological control by combined antiretroviral therapy (cART) reduces the risk of mycobacterial infections. Thus, we aimed to study cellular responses to mycobacterial antigens in 20 HIV-infected adolescents with at least one year of virological control (HIV-RNA <40 copies/mL) and 20 healthy adolescents. Methods: We evaluated CD8 and γδ T-cell degranulation by measurement of CD107a membrane expression after stimulation with lysates from BCG (10 µg/mL) and H37RA Mycobacterium tuberculosis (Mtb, 10 µg/mL). Immune activation and antigen-presenting ability were also assessed by determination of HLA-DR, CD80, and CD86 markers. Results: TCR γδ T-cell CD107a expression was similar between groups in response to mycobacterial antigens, and lower in the HIV-infected group in response to mitogen. Higher baseline HLA-DR expression and lower mycobacterial-stimulated expression was found within the HIV-infected group. Conclusions: Similar degranulation in stimulated CD8+ and TCR γδ T-cells from HIV-infected adolescents, when compared to healthy controls suggests long-term immunological preservation with immune reconstitution under successful cART. However, differences in HLA-DR expression may represent ongoing inflammation and lower specific responses in HIV-infected youth. These features may be relevant in the context of the precocity and severity of vertically acquired HIV infection.