Serum thrombopoietin and interleukin 6 concentrations in tumour patients and response to chemotherapy-induced thrombocytopenia

The relation between the number of platelets in blood and the concentrations of immunoreactive thrombopoietin (TPO), interleukin 6 and interleukin 11 (IL-6, IL-11) was studied in the sera of 32 normal subjects, of 29 untreated tumour patients and of 6 tumour patients following chemotherapy with ifosfamide, carboplatin and etoposide (ICE). Platelet counts, TPO and IL-6 concentrations were higher than normal in blood of tumour patients before chemotherapy. However, no statistical relation existed between these variables. Following chemotherapy, the number of circulating platelets decreased reaching a nadir at d 10-13, while the serum concentration of TPO increased concomitantly. Circulating IL-6 did not increase during chemotherapy-induced thrombocytopenia. IL-11 was not detectable in any serum. Thus, the reactive thrombocytosis in tumour patients could be related to elevated TPO and IL-6 levels. In contrast to circulating TPO, however, neither serum IL-6 nor IL-11 levels increase significantly in thrombocytopenia following myelosuppressive chemotherapy.