USE OF SERUM-SOLUBLE INTERLEUKIN-2 RECEPTOR LEVELS TO MONITOR THE PROGRESSION OF CUTANEOUS T-CELL LYMPHOMA

Background: The serum concentration of soluble alpha chain of the inte rleukin-2 receptor (sIL-2R) correlates with tumor burden in cutaneous T-cell lymphoma (CTCL). Therefore the sIL-2R level may be useful to mo nitor the condition of patients treated with extracorporeal photophere sis or other treatments. Objective: Our goal was to determine the util ity of serum sIL-2R as a test in monitoring of patients with advanced CTCL. Methods: Serum sIL-2R was measured serially in 36 patients with advanced CTCL treated with extracorporeal photopheresis and other moda lities (interferon alfa, methotrexate, topical nitrogen mustard, elect ron beam). Results: Serum concentrations of sIL-2R as well as lactate dehydrogenase (LDH) correlated strongly with lymph node size, but only sIL-2R correlated significantly with the severity of skin manifestati ons in erythrodermic patients. in addition, serum sIL-2R, but not LDH, was significantly higher in patients with nodal involvement. The leve l of slL-2R also was significantly higher in patients with large-cell transformation in the skin or lymph nodes compared with patients witho ut transformed disease. During treatment, serum concentrations of both serum sIL-2R and LDH correlated with changes in clinical status, but only sIL-2R showed statistically significant differences in mean level s for different relative global response scores. Pretreatment levels o f both sIL-2R and LDH correlated significantly with survival, but only sIL-2R retained significance when both were entered into the Cox prop ortionate hazards model. Conclusion: The concentration of serum sIL-2R correlates well with disease status and is more useful than LDH or Se zary cell counts to monitor clinical change in patients with advanced CTCL. Moreover, our data suggest that sIL-2R is produced at a relative ly low rate by tissue-based lymphoma cells, and that large-cell transf ormation in CTCL results in marked increase in sIL-2R production in so me patients.