Levels of Serum Soluble Interleukin-2 Receptor in Patients with Chronic Myeloproliferative Disorders

Lee, Eun Yup; Cho, Goon Jae

Abstract

BACKGROUND: A soluble form of interleukin-2 receptor (sIL-2R) is released from activated T cells. Serum sIL-2R levels are elevated in some hematological malignancies and could be used to assess disease activity and prognosis. MATERIAL AND METHODS: To define clinical usefulness and significance as a marker predicting disease progress in chronic myeloproliferative disorders, the serum levels of sIL-2R were measured in 40 cases of chronic myelogenous leukemia (CML; 25 chronic phase, 7 accelerating phase, 8 blastic phase), 3 cases of polycythemia vera (PV), 5 cases of essential thrombocythemia (ET) and 4 cases of idiopathic myelofibrosis (MF) and in 37 cases of healthy subjects using sandwich enzyme immunoassay.
RESULTS
Serum sIL-2R levels in the patients of CML, PV, ET, and MF were higher compared with the normal healthy controls. In CML, serum sIL-2R levels in the patients of blastic and accelerating phases were significantly higher than those of chronic phase. In CML of chronic phase, serum sIL-2R levels at diagnosis were related to WBC count but not to other clinical and hematologic paramaters. The leukemic cells of one patient with lymphoblastic phase of CML expressed IL-2R (CD25). Among 4 patients of CML with sIL-2R levels above 2,000U/mL at diagnosis, transformation to blastic crisis was noted in 3 patients and 2 patients died within 1 year after diagnosis. But among 11 patients of CML with sIL-2R levels below 2,000U/mL at diagnosis, only 2 patients experienced blastic crisis and died within 1 year after diagnosis.
CONCLUSION
This study indicated that serum sIL-2R levels were high in chronic myeloproliferative disorders, and that increasing levels of serum sIL-2R might be useful to predict disease progress. Further studies including more patients and longer follow-up may substantiate serum sIL-2R as a prognostic indicator in CML.