Forkhead box protein 3 super(+) regulatory T cells and Helios super(+) subset in perinatally acquired HIV

Forkhead box protein 3 (FoxP3) super(+) regulatory T cells (T sub(regs)) are important not only in regulating the development of autoimmune conditions, but also in chronic infectious diseases. Given their cardinal function in suppressing immune activation, research has focused upon whether they play a detrimental role in chronic infections, particularly HIV. While the role of T sub(regs) in HIV has been investigated intensively, it remains an unresolved topic. However, it is generally accepted that T sub(regs) are susceptible to HIV infection and are preferentially preserved over conventional CD4 super(+) T cells. It is unknown whether the peripheral-induced or the thymic-derived T sub(regs) are more susceptible to HIV cytotoxicity. It has been recognized that T sub(regs) can be segregated into two subsets based on Helios expression, with the vast majority being Helios super(+). This study examines the impact of HIV infection on total T sub(regs) and their Helios subsets in a perinatal-acquired HIV-infected paediatric population. The finding indicates a selective expansion or survival of T sub(regs) in association with CD4 depletion and increased viraemia. The Helios super(+) and Helios super(-) subsets within T sub(regs) appear to be equally affected. However, the Helios super(+) T sub(regs) seem to be more preserved in patients with low CD4 super(+) less than or equal to 25% and detectable plasma HIV RNA >20 copies/ml. In this group, the frequencies of T sub(regs) are increased, but their numbers appear insufficient to restrain immune activation. In conclusion, our findings suggest that both Helios subsets of T sub(regs) are susceptible to HIV infection and are preferentially preserved compared to conventional CD4 super(+) T cells.