Schnitzler's syndrome: increased levels of bone formation and angiogenesis factors are reduced after successful pefloxacin treatment.

Schnitzler's syndrome is characterized by chronic urticaria and monoclonal immunoglobulin (Ig) M gammopathy, with other features including intermittent fever, joint and/or bone pain with radiologic evidence of osteosclerosis, lymphadenopathy, enlarged liver and/or spleen, leukocytosis, and elevated erythrocyte sedimentation rate. The etiology of the syndrome remains obscure, although involvement of various cytokines has been proposed. Bone metabolism and angiogenesis markers are deregulated in Waldenström macroglobulinemia and IgM monoclonal gammopathy of unknown significance, but these markers have not been assessed in Schnitzler's syndrome. Herein, we report a patient with Schnitzler's syndrome who was treated with oral pefloxacin. Serum levels of osteoclast regulators, markers of bone remodeling and angiogenesis cytokines, were measured before treatment and serially after the initiation of treatment. High bone turnover and strikingly elevated levels of angiogenic cytokines were observed at diagnosis. Treatment with pefloxacin resulted in a normalization of the bone remodeling process and a significant reduction of angiogenic cytokines, with rapid and sustained improvement of symptoms, suggesting that these factors might be implicated in the pathophysiology of this syndrome. Furthermore, pefloxacin was proven to be an effective treatment for patients with Schnitzler's syndrome.