Primary and secondary autoimmune thrombocytopenia. A serological and clinical analysis

In 357 thrombocytopenic patients, the autoimmune nature of the thrombocytopenia was established with the immunofluorescence test on paraformaldehyde-fixed platelets in suspension (PSIFT). In 142 patients, autoimmune thrombocytopenia (AITP) was accompanied by (an)other disease(s) and thus classified as secondary AITP. No significant difference was found in the distribution of the immunochemical characteristics of the autoantibodies between primary and secondary AITP. The results of survival studies with 51Cr-labelled platelets and organ sequestration measurements in 7 patients with idiopathic thrombocytopenia purpura (ITP) indicated that platelets with IgM autoantibodies were sequestered mainly in the spleen. An increased incidence of AITP was seen at 5 to 10 years of age, in the 3rd decade and in the 6th and 7th decades of life. AITP was slightly more common life in females. The following groups of accompanying diseases in 142 AITP patients were distinguished: autoimmune diseases of the blood, malignant diseases of the blood, generalized and organ-specific autoimmune diseases, carcinoma and a miscellaneous group of diseases. No significant differences were found in the immunochemical properties of the autoantibodies between the various categories of disease. In 7 cases, AITP was preceded by an established viral disease, in 1 case by lepra and in another by a vaccination. The PSIFT was found to be a suitable test for diagnosing AITP not only in idiopathic thrombocytopenia, but also in thrombocytopenia associated with another disease.