T‐cell re‐population in HIV‐infected children on highly active anti‐retroviral therapy (HAART)

In this pilot study, we address the nature of the re‐population of the T‐cell compartment in HIV‐1+ (Human Immunodeficiency Virus 1), vertically infected children placed on successful regimens of HAART (highly active anti‐retroviral therapy) incorporating 2 NRTI and a protease inhibitor. The clonality of the T‐cell compartment and the abundance of RTEs (Recent Thymic Emigrants) were determined 2 weeks before and 20 weeks after initiation of HAART in a subgroup of children taking part in the PENTA (Paediatric European Network for the Treatment of AIDS) 5 trial. Analysis of the clonality of the circulating T‐cell compartment was assessed using CDR3 spectratyping and analysed using the Kolmogorov–Smirnov two sample test. This revealed that a high degree of T‐cell clonal restriction still exists 5 months into therapy, despite the appearance of previously undetectable T‐cell clones within the periphery. We detected no increase in RTE abundance in this 5 month period, as determined by PCR detection of TRECs (T‐Cell Receptor Excision Circles). We conclude that the observed re‐population of T cells within the periphery of treated children is heavily reliant upon the maintenance/expansion of pre‐existing cells during the 5 month period immediately following the initiation of therapy.