The impact of serum soluble interleukin-2 receptor levels on the diagnosis of malignant lymphoma

Soluble interleukin-2 receptor (sIL-2R) is produced by activated lymphocytes or malignant lymphoma (ML) cells. The aim of this study was to estimate the diagnostic role of serum sIL-2R levels in ML. The data of serum sIL-2R levels were extracted from the database of 1278 untreated patients admitted to Kawasaki Medical School Hospital from 1997 to 2008 and retrospectively analyzed. We compared the serum sIL-2R levels of 443 patients newly diagnosed with ML with those of 835 patients with non-hematological diseases to improve the diagnostic accuracy. The serum sIL-2R levels of patients with ML (median:1330 U/ml, range:197-84200) were significantly (p<0.001) higher than those with non-hematological diseases (median:827 U/ ml, range:106-18100). In the univariate analysis, the non-adjusted odds ratio was 3.123 and the specificity was 0.77 by adjusting the cut-off value of the sIL-2R level at 1500 U/ml. These findings suggested that sIL-2R is useful by itself in the differential diagnosis of ML. In the multivariate analysis, the adjusted odds ratio adding age ( ≧60 years), WBC counts (<10000/μ l) and CRP levels (<0.4 mg/dl) to sIL-2R were 4.047. Serum sIL-2R levels are useful for the diagnosis of ML, and the diagnostic accuracy of ML is improved by adding the other factors such as age, WBC counts and CRP levels to sIL-2R.