Background: A 45-year-old woman presented with a 20-year history of chronic idiopathic urticaria (CIU) unresponsive to H1- and H2-antagonists and combinations of other anti-inflammatory agents but controlled with daily prednisone (35 mg) for more than 13 years. Intracutaneous testing to autologous serum revealed an 8 x 10-mm wheal/flare reaction consistent with the presence of anti-Fc epsilonRIalpha autoantibodies. These autoantibodies have been reported to be present in >45% of patients with CIU. Their functional role in the pathogenesis of CIU remains poorly understood.
Objective: Because of the therapeutic refractory nature of this patient's CIU requiring high doses of corticosteroids, it was decided to initiate treatment with intravenous cyclophosphamide (CTX) in an attempt to eradicate autoantibody-producing B-lymphocyte clones. This therapeutic approach has been previously successful in other autoantibody-mediated disorders such as type II acquired angioedema and factor VIII deficiency.
Results: Initial treatment consisted of 500 mg CTX intravenously followed by increases of 100 mg every 2 weeks, with the maximum dose reaching 1,500 mg once a month, which represents approximately 20% of the dose administered during systemic cancer chemotherapy. Within 7 months there was a complete clinical remission and prednisone was discontinued. Repeat intracutaneous testing to autologous serum was negative, consistent with an abrogated autoantibody response. The patient has not experienced a recurrence of CIU at the time of this report.
Conclusion: This index case suggests that intravenous CTX may be effective in alleviating autoantibody-associated CIU in corticosteroid-dependent patients refractory to conventional therapies.