Clinical Relevance of Elevated Levels of Serum Soluble Interleukin-2 Receptor alpha (sIL-) in Patients with Non-Hodgkin's Lymphoma

Levels of soluble interleukin-2 receptor alpha (sIL-$2R{\alpha}$) 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-$2R{\alpha}$ level in non-Hodgkin's lymphoma (NHL). We used ELISA to measure the sIL-$2R{\alpha}$ levels in 48 newly diagnosed and untreated patients with NHL and evaluated the correlation between the sIL-$2R{\alpha}$ levels and clinical characteristics and the International Prognostic Index (IPI). We monitored serum sIL-$2R{\alpha}$ in 7 patients to compare the changes in their clinical progress with these levels. High levels of serum sIL-$2R{\alpha}$ (${\geq}$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 ${\geq}$472 U/L. The levels were also associated with B symptoms, bone marrow involvement, and poor response to therapy. The sIL-$2R{\alpha}$ level decreased during complete remission and was elevated during disease progression or relapse. A high level of sIL-$2R{\alpha}$ was significantly associated with a low survival rate. These results suggest that serum sIL-$2R{\alpha}$ 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-$2R{\alpha}$ in specific groups of NHL.