Complement profile in childhood immune thrombocytopenic purpura: a prospective pilot study.

Immune thrombocytopenic purpura (ITP) is a frequent, usually acute hematologic complication of viral diseases in children. Its evolution is usually benign with spontaneous resolution. Some authors have raised the hypothesis of a possible role of the complement system in the pathogenesis of ITP. In the present study, we measured the complement system components in 25 children with ITP. The complement system was abnormal in most patients with ITP as compared with the control group: 20 of the 25 patients had at least one low-component level. The most affected components were properdin, factor H (p=0.005 and p=0.001, respectively), C1q, C9, and factor B. Our results may indicate a possible role for the complement system in the pathogenesis of pediatric ITP.