Treatment of Multicentric Reticulohistiocytosis With Tocilizumab

Multicentric reticulohistiocytosis (MRH) is a rare multisystem, granulomatous debilitating disease. It affects the skin with a nodular diffuse dermatitis and the joints with a severe, potentially deforming, and handicapping arthritis. No standardized therapy exists, it is a disease with heterogeneous severity, and therefore, a diversity of therapeutic responses has been published. Current experience with anti-tumor necrosis factor agents in disease-modifying antirheumatic drug-refractory MRH cases is encouraging, and other agents such as bisphosphonates have proven effective as well. Histological analysis of the granulomatous inflammatory lesions have shown the presence of cytokines including tumor necrosis factor alpha, interleukin 1, and interleukin 6; the presence of the latter makes tocilizumab a plausible alternative. In this article, we report a 35-year-old woman with MRH refractory to a combined scheme of prednisone and methotrexate, both at high doses, and who received tocilizumab achieving remission on both cutaneous and articular symptoms. Our patient markedly improved by the second infusion (8 mg/ kg monthly), and after 9 infusions, she remained asymptomatic; no toxicity was detected. Tocilizumab could be an alternative for disease-modifying antirheumatic drug-refractory MRH.