BACKGROUND: HIV-positive persons are at elevated risk of developing the malignant diseases that require allogeneic stem cell transplantation (ASCT). Recent data suggests these individuals are at elevated risk of certain complications post-ASCT. This risk may result from pre-existing HIV-related factors affecting dynamics of immune reconstitution post-ASCT. However, to date, there has been little work describing the dynamics of immune reconstitution post-ASCT in HIV-positive persons, and none comparing these data to HIV-negative controls.

METHODS: We assessed T-cell reconstitution in six HIV-positive ASCT recipients (HIV+ASCT) compared to a control population of 21 HIV-negative ASCT recipients. In a subset of HIV+ASCT recipients we performed additional flow cytometry profiling of CD8+ T-cell subsets and antigen specificity of reconstituting CD4+ and CD8+ T-cells.

RESULTS: We observe no difference in post-ASCT CD4+ T-cells between HIV+ASCT and HIV-negative ASCT recipients, despite much lower pre-ASCT CD4+ T-cell counts in the HIV+ASCT group. In contrast, we observed significantly higher CD8+ T-cell numbers in the HIV+ASCT group post-ASCT. The reconstituting CD8+ T-cells were predominantly CD45RO+, while homing markers and antigen specificity of these cells varied between participants.

CONCLUSION: This study represents the most extensive characterisation of immune-reconstitution post-ASCT in HIV-positive persons, and the first to compare these data to HIV-negative ASCT controls. The results indicate that immune reconstitution in this group can be affected by pre-existing HIV infection and post-ASCT antigen exposure.