Background: Tumor growth in multiple myeloma (MM) is regulated by the cytokine networks which are produced by myeloma cells and the microenvironment of the bone marrow. Interleukin-17 (IL-17) is implicated in the increased angiogenesis in the bone marrow of MM. Recent studies reported elevated levels of interleukin 17A (IL-17A) in the sera of patients with advanced stages according to Durie-Salmon classification.
Material/Methods: We compared the concentration of IL-17A and IL-17E in the blood serum of 34 newly diagnosed MM patients with healthy subjects’ sera. We also evaluated the concentration of IL-17A and IL-17E in the blood serum of MM patients and the relation to the percentage of plasma cells and other clinical parameters. The concentration of IL-17E and IL-17A of healthy subjects and patients with MM was assessed by enzyme-linked immunosorbent assay (ELISA).
Results: Our data confirm that IL-17A and IL-17E serum levels were significantly higher in all MM patients and also in patients with advanced stage compared with healthy subjects. We found the correlation between serum levels of IL-17A in MM patients and percentage of plasma cells. Our results also showed that if serum levels of IL-17E were higher in MM patients, the percentage of plasma cells and beta-2-microglobulin levels were lower.
Conclusions: The IL-17 family of cytokines may suppress or promote tumor growth. There seems to be some balance between the effects of IL-17A and IL-17E. The role of increased levels of IL-17E needs further investigation to understand its role in the pathobiology of MM.

Keywords: Multiple Myeloma - physiopathology, Interleukin-17 - metabolism, Enzyme-Linked Immunosorbent Assay, Bone Marrow - physiopathology, Aged, 80 and over, Neovascularization, Pathologic - physiopathology