HIGH SERUM IL-2 LEVELS ARE PREDICTIVE OF PROLONGED SURVIVAL IN MULTIPLE-MYELOMA

Summary. In this study we analysed serum IL‐2 levels in 61 patients with multiple myeloma (MM). Patients serum IL‐2 levels were significantly higher than normal controls. Moreover, higher serum IL‐2 levels were associated with a prolonged actuarial survival. In particular, 87% of the MM patients with IL‐2 ≥ 10 U/ml are still alive at 5 years while only 13% of the remaining patients with IL‐2 < 10 U/ml are alive. The multivariate analysis confirmed these data indicating that high serum IL‐2 levels are the most useful predictor index of longer survival in MM patients. Furthermore, among the 50 patients in whom serum beta‐2‐microglobulin (SB2M) determination was available we observed that all patients with serum IL‐2 levels ≥ 10 U/ml had SB2M < 6 μg/ml, whereas in patients with serum IL‐2 < 10 U/ml SB2M ranged from 1.3 to 15 μg/ml. Using these two parameters we were able to identify three groups of patients with different survival duration. Group A (9 patients) defined by serum IL‐2 ≥ 10 U/ml and SB2M < 6 μg/ml in which all patients are alive; group B (26 patients) characterized by serum IL‐2 < 10 U/ml and SB2M < 6 μg/ml in which 24% of patients are alive and group C (15 patients) characterized by serum IL‐2 levels < 10 U/ml and SB2M ≥ 6 μg/ml in which the actuarial survival curve drops to 0 at 2.5 years. A statistically significant difference was observed between groups A and B (P < 0.05), groups A and C (P < 0.01) and groups B and C (P < 0.01). These data could reflect the existence of an active T cell control on B cell neoplasia and may suggest the opportunity of a more extensive use of recombinant biological modifiers such as IL‐2 in the therapeutic strategy of MM. Copyright © 1990, Wiley Blackwell. All rights reserved