Functional state of CD4+ and CD8+ T lymphocytes and their role in the slow progression of HIV infection in pediatric patients [Estado funcional dos linfócitos T CD4+ e CD8+ e seu papel na progressão lenta da infecção por HIV em pacientes pediátricos]

Objective: to evaluate simultaneously the functional state of cd4+ and cd8+ t lymphocytes from venezuelan hiv-1-infected pediatric patients. methods: children were assigned to subgroups of rapid progressors (rps) and slow progressors (sps),based on clinical features. to determine the degree of cd4+ and cd8+ t-lymphocyte functionality,flow cytometry techniques were used,and diverse parameters of the functionality of these cells were characterized by ex vivo tests,such as expression of cd95/ fas and cd127,and frequency of apoptosis. in addition,we determined,in cultured peripheral blood mononuclear cells,hiv-specific proliferation and the production of interleukin-10 (il-10),tumor necrosis factor alpha (tnf-α) and interferon gamma (ifn-γ),besides measuring intracellular ifn-γ in cd4+ t cells. results: our results indicate that several molecular and cellular mechanisms of cd4+ and cd8+ t lymphocytes are deteriorated in rps in comparison with sps and controls. indeed,both types of t lymphocytes from rps exhibited an increased expression of cd95/fas (p < 0.01),a significantly reduced expression of cd127 (p < 0.01),and an augmented frequency of apoptosis (p < 0.01). furthermore,t cells from these patients displayed a diminished capacity of mitogen proliferation (p < 0.05),a reduced percentage of ifn-γ producing cd4+ t lymphocytes (p < 0.05),and a smaller capacity of il-10,tnf-α and ifn-γ production (p < 0.01) in comparison with sp and control patients. conclusion: our findings indicate that the decline of the normal t lymphocyte molecular and cellular responses is related to a rapid progression and a decreased resistance to hiv-1 infection in children. copyright © by sociedade brasileira de pediatria.