Serum and CSF levels of IL-2, sIL-2R, TNF-alpha, and IL-1 beta in chronic progressive multiple sclerosis: expected lack of clinical utility. We measured interleukin-2 (IL-2), soluble IL-2 receptor (sIL-2R), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta) by ELISA in paired sera and CSF from 50 chronic progressive multiple sclerosis (CPMS) patients during worsening disability, 19 patients with other neurologic diseases (OND), and in sera from 40 healthy volunteers. In the CPMS patients, 28% (14/50), 10% (5/50), 16% (8/50), and 6% (3/50) had elevated serum levels of IL-2, sIL-2R, TNF-alpha and IL-1 beta, respectively, compared with healthy controls. The only analyte we detected in the CSF was IL-2 in 1 CPMS patient (1/50, 2%). We also saw elevated serum sIL-2R in 16% (3/19) of OND patients. We found no significant difference in mean levels of serum sIL-2R between the 3 groups. Our study, the largest to date of CPMS patients, shows that serum and CSF levels of IL-2, sIL-2R, TNF-alpha, or IL-1 beta are not sensitive for, and the serum sIL-2R level is not specific for, CPMS. Therefore, measurement of these analytes will not be clinically useful for therapeutic or prognostic purposes in the majority of CPMS patients. 