Myeloproliferative disease in patients with a history of multiple blood donations: a report of 8 cases

Background. The clonal origin of myeloproliferative disorders has been clearly demonstrated and it is known that reactive thrombocytosis occurs as a non specific response to various inflammatory or neoplastic conditions. Only a few papers have discussed the topic of myeloproliferative diseases in blood donors. Materials and Methods. We report 8 cases of myeloproliferative diseases (3 polycythemia vera and 5 essential thrombocythemia) in blood donors out of a total of 44 myeloproliferative disorders diagnosed in our Department during the last 5 years on the basis of the criteria established by the Polycythemia Vera Study Group criteria. As controls we considered 61 patients with reactive thrombocytosis referred to our Department in the same period of time. The estimated odds ratio was calculated according to standard methods. Results. The prevalence of blood donors with myeloproliferative disorders was 18.1%, while that of donors with reative thrombocytosis was 3.2%. The estimated odds ratio was 6.56 with a 95% confidence interval between 1.07 and 17.3. No other single factor except blood donations was frequent in the past history of these patients. Conclusions. Our data seem to indicate that both thrombocytosis and erythrocytosis resembled primary forms in these subjects; however, none of them suffered serious thrombotic and/or hemorrhagic symptoms. Our study indicates the importance of paying due attention to the blood cell counts of blood donors.