Serum thrombopoietin and plasma glycocalicin concentrations as useful diagnostic markers in thrombocytopenic disorders.

Using enzyme-linked immunosorbent assays, we measured the concentrations of serum thrombopoietin (TPO) and plasma glycocalicin, a proteolytic fragment of platelet glycoprotien Ib alpha, in 13 patients with myelodysplastic syndrome (MDS), aplastic anaemia (AA) or idiopathic thrombocytopenic purpura (ITP). In the patients with AA or MDS, the TPO concentrations were remarkably increased, and their glycocalicin concentrations were decreased compared with the normal control individuals. In the patients with ITP, however, the TPO and glycocalicin levels were not changed as much as in the AA/MDS patients in spite of the same degree of thrombocytopenia. During immunosuppressive treatment of ITP patients, there was an inverse relationship between the level of TPO and the platelet count. Thus, measurements of TPO and glycocalicin levels are useful for the diagnosis of thrombocytopenia, and our results from ITP patients did not support the model which suggested the simple feedback regulation of TPO in thrombocytopenia.