BMSC and H929 (A) and HOB and H929 (B) cells were co-cultured for 24 hours. After 24 hours, co-cultures were left untreated or exposed to melphalan [50ug/ml] for 24 hours. Following treatment, cells were rinsed, media replaced, supernatants collected at 2, 4, 6 and 8 hours post-treatment and an IL-6 ELISA completed. Melphalan exposure significantly decreased IL-6 protein expression. Log transformed ANOVA and Tukey post hoc tests were used for statistical analysis (* represents p<0.05).