PARTIAL COMPLEMENT DEFICIENCIES IN IDIOPATHIC THROMBOCYTOPENIA OF CHILDHOOD

We have examined the classical complement activation pathway in 36 chi ldren with idiopathic thrombocytopenia (ITP) in a retrospective study. An increased prevalence of congenital, partial complement deficiencie s is found in ITP. Homozygous C4A deficiency was found in 5 patients ( p < 0.05) and heterozygous C2 deficiency in 2 other patients (p = 0.05 ). We suggest that some cases of childhood ITP belong to the immune co mplex mediated diseases, such as systemic lupus erythematosus and that abnormal immune complex formation and clearance may lead to ITP.