Monoclonal gammopathy (MG) in patients with angioedema, urticaria, respiratory allergies, and other dermatologic manifestations

Abstract

Rationale Schnitzlers syndrome (SS) is a rare disorder whose main components are neutrophilic urticaria, MG, fever, osteosclerosis, elevated ESR and WBC. MG has also been observed in angioedema with acquired C1INH deficiency, resulting from a consumptive process by idiotype-antiidiotype immune complexes or from an autoantibody against C1INH. Methods We review 11 patients with MG presenting with various “allergic” manifestations to determine if a syndrome including MG exists among a wider range of allergy patients. Results Five of our 11 patients might be considered variants of SS in that urticaria and MG were present (2 also had angioedema). However, since other characteristics of SS were absent and urticaria was clinically typical, they are more likely a different entity. The other 6 patients had various combinations of angioedema (3 patients), respiratory allergies and/or other dermatologic manifestations except case 11, which had only allergic rhinitis and chronic sinusitis. Patients with angioedema had normal C1INH levels. Conclusions We postulate that the mechanisms of angioedema in our patients with MG are similar to that in acquired C1INH deficiency with idiotype-antiidiotype antibodies triggering the inflammatory cascade with possible consumption of C1INH, albeit insufficient to depress C1INH activity levels. Also, we postulate that increased B cell activity might result in a single clone of plasma cells under the “clonal hypothesis” theory even in the absence of urticaria. The allergist must be vigilant for MG in the atopic individual particularly in the presence of urticaria, angioedema or chronic infection. Serum protein electrophoresis is a good screening tool.