THE DIAGNOSTIC-VALUE OF THROMBOPOIETIN LEVEL MEASUREMENTS IN THROMBOCYTOPENIA

it has been reported that blood trombopoietin (TPO) levels can discrim inate between thrombocytopenia due to increased platelet destruction a nd decreased platelet production. With our TPO ELISA and a glycocalici n ELISA we analysed a large group of patients in detail and could conf irm and amplify the above notion in detail. TPO levels were determined in plasma from 178 clinically and serologically well-defined thromboc ytopenic patients: 72 patients with idiopathic autoimmune thrombocytop enia (AITP), 29 patients with secondary AITP, 5 patients with amegakar yocytic thrombocytopenia and 72 patients who suffered from various dis eases (46 in whom megakaryocyte deficiency was not and 26 in whom it w as expected). In addition, we measured the level of glycocalicin as a marker of total body mass of platelets. In all patients with primary A ITP and secondary AITP, TPO levels were within the normal range or in same (n = 7) cases only slightly increased. The level of glycocalicin was not significantly different from that of the controls (n = 95). Th e patients with amegakaryocytic thrombocytopenia had strongly elevated TPO levels and significantly decreased glycocalicin levels. Similarly , among the 72 thrombocytopenic patients with various disorders, eleva ted TPO levels were only found in patients in whom platelet production was depressed. The mean level of glycocalicin in these patients was d ecreased compared to that in controls and patients with AITP, but was not as low as in patients with amegakaryocytic thrombocytopenia. In co nclusion, all patients with depressed platelet production had elevated levels of circulating TPO, whereas the TPO levels in patients with an immune-mediated thrombocytopenia were mostly within the normal range. Therefore, measurement of plasma TPO levels provides valuable diagnos tic information for the analysis of thrombocytopenia in general. Moreo ver, treatment with TPO may be an option in AITP.