Natural killer cell function in multiple myeloma is impaired by dexamethasone and can not be rescued by immunomodulatory drugs

Abstract

Abstract The immunomodulatory (IMiD) drug Lenalidomide (Len) is known to stimulate natural killer (NK) cells and enhance anti-tumor responses. Len plus Dexamethasone (Dex) therapy (Len-Dex) is an effective treatment for multiple myeloma (MM). As part of a prospective clinical trial of monthly cycles of Len-Dex therapy we assessed NK cell number and function in 25 MM patients. Whilst NK numbers increased from a mean of 2×105/ml (baseline) to a mean of 3.9×105/ml (cycle 6) (p=0.05), the mean NK cell-mediated cytotoxicity in chromium assays against K562 significantly decreased from 48.9% to 27.6% respectively (p=0.0028). Further analysis showed that when NK cell cytotoxicity was ..