Interleukin-17 receptor expression on vascular endothelial cells of masses of skeletal extramedullary disease in myeloma patients

The goal of the study was to investigate the expression of interleukin-17 (IL-17) and IL-17 receptor (IL-17R) in patients with myeloma bone diseases (MBD) and skeletal extramedullary disease (skeletal EMD). The levels of IL-17 were determined using ELISA. The expression of IL-17R on vascular endothelial cells of bone marrow (BM) and masses of skeletal EMD was detected using immunohistochemistry. The results showed an elevated IL-17 level in BM of BMD and skeletal EMD patients. The microvessel density (MVD) was significantly increased in the masses of skeletal EMD. IL-17R was almost exclusively expressed by endothelial cells, not by myeloma cells in the masses of skeletal EMD patients. We concluded that EMD masses showed increased angiogenesis mediated by IL-17 pathway and in part this may help in myeloma cell-growth under these conditions.