Microsoft Word - AHA063BF

M.L. Randi, F. Fabris, C. Vio, A. Girolami, University of Padua, Institute of Medical Semeiotics, Via Ospedale, 105‚ I-35100 Padua (Italy) Several instances of familial polycythemia vera (PV) have been described [1,6, 9]; however, no data are available on the incidence of primary or secondary thrombocytosis in the same family. Over the last 10 years we have studied 170 subjects with thrombocytosis. 133 of them (65 males and 68 females) presented a primary form: 63 essential thrombocythemia (ET), 52 PV, 5 myelofibrosis with mye-loid metaplasia (MMM) and 13 chronic myeloid leukemia (CML). The other patients (37 cases, 16 males and 21 females) showed a secondary thrombocytosis due to neoplasms, miscellaneous chronic conditions or splenectomy. The platelet count was performed in EDTA blood by phase microscope using the Un-opette diluting system (Beckton-Dickinson, USA). Platelet aggregation was performed as previously described [2] under stimuli with ADP 2 μM, adrenalin 10 μM and collagen 2μg. The platelet aggregation was expressed as normal, increased or decreased in comparison to 100 controls comparable for sex and age. Platelet serotonin content (5-HT) was evaluated by a modification of the method proposed by Udenfriend as previously described [3] (normal value: 1.5–3 nM/109platelets). In the primary thrombocytosis group we have found only 2 related subjects (1.5%) out of 133 patients. They were 2 sisters, one with PV (patient 1) and the other with an ET (patient 2). For the diagnosis we accepted the criteria proposed by Polycythemia Vera Study Group [1]. The main features of the 2 selected patients are summarized in the following table: