Prognostic significance of serum soluble interleukin-2 receptor level in non-Hodgkin's lymphoma: a single center study in Japan.

Interleukin 2 receptor is expressed not only on the surface of activated T or B lymphocytes, but also on certain lymphoid malignancies. The receptor is released from the cell membrane as soluble form (sIL-2R). Serum sIL-2R level is a sensitive and quantitative marker of circulating peripheral blood mononuclear cell activation or specific tumor cell growth including non-Hodgkin's lymphoma (NHL). However, the relevance of serum sIL-2R levels relating to clinical outcome in adult patients with NHL remains uncertain. Therefore, we investigated the serial serum sIL-2R levels in 28 untreated patients with NHL to evaluate its correlation with clinical characteristics. High serum sIL-2R level (>1000 U/ml) at diagnosis was associated with a high incidence of treatment failure (p=0.03) and poor overall survival (p=0.057). The serum sIL-2R levels decreased significantly after achieving complete remission (p=0.003). Further larger studies are required to evaluate whether serum sIL-2R level is an independent prognostic factor or not. However, adding this parameter to those already employed in the International Prognostic Index would perhaps provide a better prognostic index for adult patients with NHL.