INCREASED SERUM CONCENTRATION OF THE SOLUBLE INTERLEUKIN-2 RECEPTOR IN CUTANEOUS T-CELL LYMPHOMA - CLINICAL AND PROGNOSTIC IMPLICATIONS

Background and Design: The serum concentration of soluble alpha-chain receptor for interleukin-2 (sIL-2R) was determined in 101 patients wit h cutaneous T-cell lymphoma (CTCL). Results: The serum concentration o f sIL-2R correlates positively with CTCL tumor burden as determined by several clinical parameters tie, clinical subtype of disease, extent of skin involvement, T rating, and stage), by serum lactate dehydrogen ase concentration, and by Sezary cell counts in erythrodermic disease. The median value of sIL-2R in erythrodermic CTCL was more than threef old higher than that of classic mycosis fungoides (MF). The proportion of patients with elevated sIL-2R concentration (>1000 U/mL) also incr eased in CTCL in a similar fashion according to the clinical type of d isease (MF patch phase, 15%; MF plaque phase, 33%; MF tumor phase, 47% ; and erythrodermic variants, 90%). However, no correlation was found between sIL-2R serum concentration and expression of membrane-bound IL -2R alpha chain (CD25) on lymphoid cells in skin lesions and periphera l blood. Significantly, multivariate analysis of various prognostic fa ctors demonstrated that in erythrodermic CTCL, sIL-2R serum concentrat ion correlated best with survival and was a better predictor of progno sis than stage, Sezary cell counts, or lactate dehydrogenase values. C onclusions: These findings document the usefulness of the measurement of the sIL-2R serum concentration to determine tumor burden and progno sis in patients with CTCL.