[Hereditary angioneurotic edema: study of serum complement and therapeutic trial with tranexamic acid (author's transl)].

Three familial generations (five members with hereditary angioneurotic edema) have been evaluated under clinical and immunological standpoints. A therapeutic trial with tranexamic acid was carried out. The five members with hereditary angioneurotic edema showed: decreased values of total hemolytic activity (CH50), deficit of C4 (between 8 and 23 percent of the normal value), and normal levels of C3 and C9. C3PA was normal in four members and decreased in one. Asymptomatic familial members had normal serum complement levels; only three cases showed diminished values of CH50, C4, C-1-INH and C3PA. Therapeutic trial with tranexamic acid demonstrated the usefulness of this agent in the treatment of angioneurotic edema; it showed slighter adverse reactions than those derived from other therapeutic modalities. Screening of asymptomatic familial members is pointed out in order to detect low plasma values of C1-IHN.