T-lymphocyte subsets, B-lymphocyte, immunoglobulins and complement were studied in 38 children with Henoch Schonlein Purpura (HSP) in the acute stage. They had significantly lower CD3 percentage and lymphocyte blastogenesis rate, greater CD8 variation coefficient and B-lymphocyte percentage and higher levels immunoglobulins (IgA, IgG, IgM) and complement 3 than the controls. 21 (55%) of them had a low CD8 percentage. The results indicated that children with HSP had low T-lymphocyte percentages and function, increased B-lymphocyte percentage and function, high immunoglobulins, normal or elevated complement. On the other hand, no significant differences were found in the T-lymphocyte subsets values among healthy children aged 7-11 years. The normal values of T cell subsets in 35 normal controls were CD3 66-70%, CD4 37-41%, CD8 28-32%, respectively.