Clinical relevance of elevated levels of serum soluble interleukin-2 receptor alpha (sIL-2Rα) in patients with non-Hodgkin's lymphoma.

Levels of soluble interleukin-2 receptor alpha (sIL-2Rα) are known to increase in the sera of patients with certain malignancies, including malignant lymphoma. This study aimed to assess the clinical significance of the sIL-2Rα level in non-Hodgkin's lymphoma (NHL). We used ELISA to measure the sIL-2Rα levels in 48 newly diagnosed and untreated patients with NHL and evaluated the correlation between the sIL-2Rα levels and clinical characteristics and the International Prognostic Index (IPI). We monitored serum sIL-2Rα in 7 patients to compare the changes in their clinical progress with these levels. High levels of serum sIL-2Rα (≥ 2,000 U/mL) correlated well with parameters defining the high risk group according to the IPI, i.e., high tumor burden at diagnosis (stage III+IV) and lactate dehydrogenase ≥ 472 U/L. The levels were also associated with B symptoms, bone marrow involvement, and poor response to therapy. The sIL-2Rα level decreased during complete remission and was elevated during disease progression or relapse. A high level of sIL-2Rα was significantly associated with a low survival rate. These results suggest that serum sIL-2Rα might be useful as a biomarker for evaluating the prognosis of patients with NHL at the time of diagnosis and during therapy. A well-controlled, large-scale study is needed to clarify the clinical significance of sIL-2Rα in specific groups of NHL.