Abstract
Several cases of acquired C1̄ inhibitor (C1̄ INH) deficiencies and angioedema have been reported in association with lymphoproliferative diseases. An acquired C1̄ INH deficiency can be distinguished from the hereditary angioedema by the adsence of C1̄ INH deficiency in other family members, by the profound reduction of the C1 level in addition to the reduction of C4 and C2 levels, and by the presence, in most cases, of serum immunoglobulin abnormalities and of a high C1 depleting activity in the serum of a patient suffering from a lymphoproliferative disease. In addition to the three cases previously described (Blut 32: 195, 1976) we have now observed a fourth case of acquired C1̄ INH deficiency and we have studied the effect of the treatment with Danazol on the C1̄ INH and complement levels.
A 57-year-old man presented with a lymphoproliferative disease, IgM dysglobulinemia and the characteristic complement profile of an acquired C1̄ INH deficiency.
