IMPACT OF ENDOGENOUS THROMBOPOIETIN LEVELS ON THE DIFFERENTIAL-DIAGNOSIS OF ESSENTIAL THROMBOCYTHEMIA AND REACTIVE THROMBOCYTOSIS

By using the newly commercialized Quantikine(TM) human TPO immunoassay , plasma thrombopoietin (TPO) concentrations were measured in 12 patie nts with essential thrombocythaemia (ET), 13 patients with reactive th rombocytosis (RT) and 11 healthy volunteers. For the healthy volunteer s the mean plasma TPO concentration was 21.1+/-11.0 pg/ml. The mean pl asma TPO concentration in the group of RT was slightly lower (16.4+/-8 .6 pg/ml) but did not differ significantly from the control group. The mean plasma TPO concentration in ET patients (44.1+/-45.2 pg/ml) was significantly (p<0.05) higher than the mean for RT patients, but did n ot differ statistically from the mean of healthy volunteers. These dat a suggest a defective clearance of plasma TPO in patients with ET.