Acquired C1-inhibitor deficiency: 7 patients treated with rituximab.

ABSTRACT

BACKGROUND: Acquired C1-inhibitor deficiency can occur secondary to excessive C1-inhibitor consumption (type I) and be associated with a lymphoid hemopathy, or linked to the presence of anti-C1-inhibitor autoantibodies (type II) in a context of an isolated monoclonal gammopathy, sometimes associated with lymphoproliferation. Efficacy of danazol, tranexamic acid and/or corticosteroids is inconstant. Rituximab efficacy against type II angioedema has been reported. METHODS: Description of 7 rituximab-treated patients, 6 with type II acquired angioedema and 1 with type I. RESULTS: Clinical efficacy (only for type II) was complete for 3, partial for 2 and 2 were therapeutic failures. Only 2 patients had improved biological parameters, with normalization of their C1-inhibitor levels and diminished anti-C1-inhibitor autoantibodies, observed 1-9 months after the last infusion of the second rituximab cycle. An associated lymphoproliferation did not affect the response to treatment. CONCLUSION: Rituximab efficacy in the treatment of acquired angioedema is inconstant and might require repeated cycles.