Immunological study of childhood acute ITP at onset.

We attempted to search for any specific change in the immune system during the onset of childhood acute immune thrombocytopenic purpura (ITP) in order to clarify the pathophysiology of acute ITP by examining the lymphocyte subset, lymphocyte blastogenic response, serum complements, and immunoglob-ulins in 18 patients with childhood acute ITP and 18 controls (control values after normalization). At the onset of acute ITP the levels of serum complements and IgG and IgA were found to be within the normal ranges, but serum IgM levels were paier than 200 mg/dL in six cases among 18 patients. Lymphocyte blastogenic response to phytohemagglutinin (PHA) and concanavalin A (ConA) was depressed in patients relative to controls (PHA: p < 0.05, ConA: p < 0.01). Lymphocyte blastogenic response to pokewood mitogen (PWM) was lower than that of the control, but no statistical significance was observed. There was no difference in the proportion of CD3, CD4, CD8, SmIg, SmIgG, SmIgM, SmIgA, and SmIgD. The CD4/CD8 ratio was ...