[Studies on the thrombocytopoietic factor. II. Determination of thrombocytopoietic activity in patients with hematological syndromes (preliminary study)].

Using the biological test on rats the thrombocytopoietic activity (AT) was determined in sera of 13 patients with idiopathic thrombocytopenia (ITP), 5 patients with pancytopenia and bone marrow hypoplasia, 18 with thrombocytopenia developing during proliferative diseases of the haemopoietic system, and 4 patients with erythremia vera. A high mean thrombocytopoietic activity was demonstrated in ITP and this high activity was accounted for by significantly raised AT in acute thrombocytopenia. Increased AT was observed also in myeloproliferative syndromes associated with thrombocytopenia, while in pancytopenia with bone marrow hypoplasia and in erythremia vera AT seemed not increased independently of the stage of the disease. Greater number of cases will be necessary for drawing reliable conclusions.