Serum level of interleukin-16 in multiple myeloma patients and its relationship to disease activity

Interleukin-16 (IL-16) is a chemoattractant of CD4+ lymphocytes, and it has been implicated in the pathogenesis of various inflammatory diseases. There is evidence that it may have a role in multiple myeloma (MM). In the present study, we determined the serum level of IL-16 both before and after treatment of MM and related it to inflammatory markers and survival. Forty-eight newly diagnosed MM patients were included in the study. Disease stage was defined using the Durie-Salmon classification system (10 patients were in stage I, 19 in stage II, and 19 in stage III). After standard treatment, 22 patients reached the plateau phase and were re-evaluated. The following serum parameters were measured: IL-16, IL-6, alpha-1 antitrypsin (alpha1AT), and C-reactive protein (CRP). Survival was determined as the number of months elapsed since original diagnosis. The mean +/- SD of serum IL-16 was 343 +/- 195 pg/ml in the pre-treatment MM group and 101 +/- 30 pg/ml in the control group. All measured parameters were higher in the patient group compared to healthy controls. Furthermore, IL-16, IL-6, alpha1AT, and CRP were significantly increased with increasing stage of disease, from stage I to stage III (P<0.01). All parameters decreased significantly following effective chemotherapy (P<0.002). Patients with a high level of IL-16 (>430 pg/ml) displayed an inferior survival time in comparison to those with lower levels of IL-16. In the pre-treatment group, IL-16 correlated with alpha1AT and IL-6 (r=0.374, P<0.01 and r=0.454, P<0.002, respectively). IL-16 may play a role in multiple myeloma; however, further functional studies are required.