Circulating erythroid and megakaryocytic progenitors in polycythaemia vera and essential thrombocythaemia

Abstract

We studied the behaviour in culture of erythroid and megakaryocyte progenitor cells (BFU‐E, CFU‐MK) obtained from peripheral blood (PB) in 38 patients: 15 with essential thrombocythaemia, 3 with reactive thrombocytosis, 16 with polycythaemia vera and 4 with secondary polyglobulia. Clonal erythroid growth without added erythropoietin was observed in all patients with polycythaemia vera and in 5 out of 15 with essential thrombocythaemia, but in none of the patients with reactive thrombocytosis or secondary polyglobulia or in controls. When the CFU‐MK were cultured without phytohaemagglutinin‐stimulated medium (PHA‐LCM), all patients with essential thrombocythaemia and 7 out of 16 with polycythaemia vera showed circulating CFU‐MK but none of those with reactive thrombocytosis or secondary polyglobulia or controls did so. This study indicates that the growth in vitro of megakaryocyic and erythroid progenitors from such a readily available source as peripheral blood can be valuable in the diagnosis of certain borderline cases of thrombocytosis or erythrocytosis.