Interleukine-17 reduced serum levels in BRONJ patients after bisphosphonates administration

Patients treated with intravenous bisphosphonates have been shown to develop osteonecrosis of the jaws. Objectives: because it has been proposed that bisphosphonates can modify angiogenic activity, this study evaluated serum concentrations of Interleukin-17, that exhibits angiogenic activity regulating the production of proangiogenic factors, in patients affected by multiple myeloma (MM) and treated with bisphosphonates and in MM subjects showing osteonecrosis of the jaw (BRONJ). Methods: three groups were included: 1) seven subject with MM and BRONJ, 2) eighteen patients with MM without BRONJ, 3) eight normal patients as control. A venous blood sample was taken from all patients and serum levels of IL-17 were measured by standard quantitative sandwich ELISA kits (Quantikine; R&D Sistems Minneapolis, MN, USA). Comparison between two or more groups was performed by the unpaired Student t test. Statistical significance was considered at p<0, 05. Results: group 2 and 3 presented similar IL-17 serum values (54, 11± 28, 22 pg/ml vs 58,75± 18,63 pg/mL; p n.s.).After administration of bisphosphonates group 2 (MM no BRONJ subjects) showed a decrease of IL-17 (21, 83± 18,43 pg/mL; p < 0,001). Group 1 (MM subjects with BRONJ) presented a reduction of IL7 compared to controls although they had interrupted bisphosphonates administration for several months (35,42± 33,52 pg/mL; p<0,05). Conclusions: these data seem to confirm the hypothesis that bisphosphonates could have an anti angiogenic effect able to cause the onset of osteonecrosis and suggest the possibility to use a target therapy to restore a normal angiogenic cytokines pattern.