Therapeutic immunisation benefits mucosal-associated invariant T-cell recovery in contrast to IL-2, GM-CSF, and rhGH addition in HIV-1+ treated patients: individual case reports from phase I trial.

MAIT cell populations are reduced in frequency in HIV-1+ patients, and this disruption is associated with systemic immune activation. Reconstitution of MAIT frequency may benefit HIV-1 infected individuals, however only recently has in vivo work been endeavoured. Treatment with IL-2, GM-CSF and rhGH immunotherapy combined with an HIV-1 vaccine in the context of ART has shown to reconstitute CD4 T-cell population numbers and function. In this study cryopreserved peripheral blood mononuclear cells (PBMC) from 12 HIV-1+ patients who were undergoing a combination of HIV-1 vaccine and/or IL-2, GM-CSF and rhGH immunotherapy in conjunction with ART were analysed to assess the potential of this treatment to promote MAIT cell proliferation. PBMC were thawed from study baseline, week 2 and week 48 time-points, fluorescently stained for MAIT cell markers and assessed by flow cytometric analysis. Matched pairs and inter-group results were statistically compared using appropriate methods. MAIT cell frequency was increased from baseline at 48 weeks in participants who received vaccine only, whereas individuals receiving IL-2, GM-CSF and rhGH immunotherapy with or without vaccine did not show additional benefit. Whilst IL-2, GM-CSF and rhGH treatment promotes CD4 T-cell reconstitution and HIV-1-specific T-cell function, it does not support MAIT cell recovery in patients on suppressive ART. Therapeutic immunisation however has a positive effect, highlighting the importance of aiming for balanced promotion of T-cell population reconstitution to impact on HIV-1 transmission and pathogenesis.