Decreased C'-1q protein concentration and agglutinating activity in agammaglobulinaemia syndromes: an inborn error reflected in the complement system.

Abstract

In both C'1q protein and agglutination assays, markedly reduced mean titres (27 and <10% normal, respectively) were observed in Swiss type lymphopenic agammaglobulinaemia. Mean C'1q titres were somewhat decreased in other forms of agammaglobulinaemia, but not to the same degree (78 and 46% normal, respectively). C'1q titres were normal or elevated in other diseases associated with repeated infections and malignancy.