Intraorbital injection of Rituximab in idiopathic orbital inflammatory syndrome: case reports.

To analyze the clinical and histopathological effects of low doses of intraorbital and intralesional Rituximab (RTX) in three patients affected by idiopathic orbital inflammatory syndrome (IOIS). Three patients with IOIS were enrolled, all of whom underwent lesion biopsy to confirm the diagnosis, complete blood examinations (thyroid function tests, complete blood cell count, fasting blood glucose, liver and renal function tests, erythrocyte sedimentation rate, serum ACE, C-reactive protein, rheumatoid factor, antinuclear antibody, antineutrophil cytoplasmic antibody, serum IGg4 level tests) and magnetic resonance imaging (MRI). Patients received the planned treatment schedule, consisting of a complete cycle of intraorbital injections of RTX (MabThera(®); Roche, Basel, Switzerland, 100 mg/10 ml): 10 mg, once a week for 1 month (four injections/month), in two patients repeated. The clinical and imaging follow-ups were at an average of 17.6 months (range 14-24 months) after treatment. A post-treatment bioptic procedure was performed in one patient. All patients showed a significant MRI reduction of the orbital lesion and a stable clinical improvement for the follow-up time of observation. The post-treatment histopathological specimen showed a disappearance of inflammatory cells. Low doses of intralesional RTX, which are safe, efficacious and used in other B cell-mediated disorders, are a useful treatment in IOIS, with decreased risks of generalized immunosuppression and fewer side effects than are afforded by systemic high doses of glucocorticoids and RTX. The result is very quick, effective and prolonged on the inflammatory component of the disease and seems to be related to the histologic reduction of infiltrating CD20+ lymphocytes.