Serum-soluble interleukin-2 receptors in B-cell lymphoproliferative malignancies

The levels of soluble interleukin-2 receptors (sIL-2R) were determined in the serum of 53 patients with B-cell lymphoproliferative malignancies, including 31 patients with non-Hodgkin lymphomas (NHL), 16 with chronic lymphocytic leukemia (CLL), and 6 with multiple myeloma. In addition, serum samples from 40 patients with various solid tumors as well as from 53 healthy individuals were used as controls. It was found that the mean serum levels of sIL-2R were significantly increased (P less than 0.001) in NHL (mean +/- standard error of the mean 2,327 +/- 320 units/ml) and CLL patients (2517 +/- 451 units/ml) as compared to normal controls (207 +/- 17 units/ml). No such difference was observed when the serum sIL-2R levels of patients with multiple myeloma or solid tumors were analyzed. Serum sIL-2R levels were closely related to the clinical stage, the presence of B-symptoms, and the disease activity of patients with NHL and CLL. In fact, response to chemotherapy was followed by marked decrease or normalization of sIL-2R levels, while in a number of patients sIL-2R values were even able to predict disease relapse. Finally, no association with histologic grade in NHL patients, could be demonstrated. We conclude that serum sIL-2R (1) are increased only in B-NHL and B-CLL but not in myeloma patients, (2) are related to the tumor burden, and (3) can serve as a valuable tumor marker for the monitoring of patients treatment.