Different patterns of platelet turnover in chronic idiopathic thrombocytopenic purpura.

Platelet turnover, platelet production, platelet mean life span (MLS), platelet count, mean platelet volume (MPV) and platelet-associated antibodies have been examined in 26 patients with chronic idiopathic thrombocytopenic purpura (ITP) and in 1 patient with hypomegakaryocytic thrombocytopenia (HT). 15 ITP patients had normal or increased platelet turnover and platelet production, while 11 had subnormal values despite shortened MLS, while the patient with HT had normal MLS. The differences between the two groups with high and low platelet turnover were statistically significant. No correlation was found between kinetics parameters and bone marrow pattern in a total of 19 patients examined. These data suggest that in some cases of chronic ITP, the pathogenesis of thrombocytopenia can be due not only to the peripheral destruction of platelets, but also to a deficient platelet production by megakaryocytes. Since the number of megakaryocytes in bone marrow slides is not decreased in the low turnover compared with the high turnover group, it is possible that an impaired pattern of megakaryocyte maturation be the cause of the low platelet production in these patients, unlike in the HT patient where megakaryocytes are almost absent.