Detection of soluble interleukin-2 receptor in the serum of patients with non-Hodgkin's lymphoma

BACKGROUND: Patients with non-Hodgkin's lymphoma (NHL) have increased serum levels of soluble interleukin-2 receptor (sCD25). In this study the authors investigate: al the value of sCD25, compared to other serum markers, as tumor marker, and bl the relationship of the sCD25 with the response to therapy and prognosis. PATIENTS AND METHODS: Serum interleukin-2 receptor (sCD25) levels were measured at diagnosis in 63 patients with NHL (low-grade lymphoma 30 and high-grade lymphoma 33). RESULTS: High levels of sCD25 were found in these patients compared to a control group (median 1,757 U/ml vs 385 U/ml; p < 0.0001). Significant differences were also found between the high-grade group and the low-grade group, as a whole and within the same Ann Arbor stage, sCD25 showed a correlation coefficient higher than other serum parameters (albumin, LDH, beta 2-microglobulin, uric acid, C-reactive protein) with Ann Arbor stage and with the number of involved lymph nodes or extralymphatic organs. In the high-grade NHL, the median of sCD25 (3,000 U/ml) separates patients with differences in the overall survival (p = 0.0138) and in percentage of complete remisions (p = 0.0079). All the patients with sCD25 less than or equal to 3,000 U/ml reached the remision. The association sCD25 > 3,000 U/ml and albumin < 3.5 g/dl selected to 5 out of 6 patients who failed induction chemotherapy and only 2 out of 22 who reached the remision. CONCLUSIONS: The sCD25 is the best serum factor for estimating tumor burden in NHL. sCD25 level isolates or associated with albumin provides prognostic information.