Platelet antibodies in different forms of chronic thrombocytopenia.

Three techniques have been employed for the in vitro detection of circulating platelet antibodies in thrombocytopenic patients affected by 'idiopathic' form or by lupus erythematosus (SLE), the complement fixation test, the platelet factor 3 availability test and the serotonin release test. 29 of the 35 sera tested (82.8%) gave positive results for antiplatelet activity. In particular the serotonin release test allows to distinguish 4 groups of patients: a first group affected by idiopathic form; two groups with autoimmune thrombocytopenia and various degrees of serotonin release, and finally a fourth group which comprises subjects affected by SLE, with circulating immunocomplexes.