Circulating RANKL/OPG in polymyalgia rheumatica.

OBJECTIVE: To evaluate whether RANKL/OPG balance is modified in PMR patients, either in the active phase of the disease or during corticosteroid treatment. METHODS: Circulating levels of RANKL and OPG were assayed by enzyme-linked immunosorbent assay in PMR patients with active untreated disease and in patients treated by corticosteroids over a 12-month follow-up period. RESULTS: We found no statistically significant differences in circulating levels of OPG between PMR patients either in the active phase of the disease or during all follow-up period compared to normal controls. On the other hand, systemic production of sRANKL is increased and is not modulated by corticosteroid treatment. CONCLUSION: In PMR increased levels of sRANKL may be related to bone osteoporosis. Further investigations are necessary to evaluate the relationship between the RANK/RANKL/OPG system and bone turnover in PMR patients.