Sub-units of the first complement component in immunologic deficiency syndromes: independence of Cls and Clq

Abstract

Normal concentrations of C1 esterase, C1s, have been found in nineteen individuals with a variety of immunologic deficiency syndromes. C1q levels are markedly low in patients with lymphopenic hypogammaglobulinaemia. The lack of correlation of serum concentrations of C1s with C1q in several patients suggests a separate mode of synthesis or catabolism for these C1 subunits. Furthermore, the extreme C1q deficiency in lymphopenic hypogammaglobulinaemic patients may play a role in their serious prognosis; however the normal C1s concentrations would allow some complement mediated functions.