Guinea pigs with inherited deficiencies of complement components C2 or C4 have characteristics of immune complex disease

Abstract

Guinea pigs genetically deficient in the second (Cs) or fourth component of complement (C4) generally appear healthy in contrast to humans with a C2 or C4 deficiency. However, upon investigation of these genetic deficiencies in guinea pigs for signs of dysregulation in the humoral immune system and especially autoantibodies, many complement-deficient guinea pigs (>50%) had elevated levels of serum IgM and higher concentrations of anti-hapten (dinitrophenyl) antibodies as signs of polyclonally stimulated antibody synthesis. In addition, a significant number of the complement-deficient animals, on average 30%, had IgM rheumatoid factors in their sera compared with <1% of the normal animals. These observations, therefore, indicate that guinea pigs, genetically deficient in C2 or C4, show characteristics of immune complex disease in general.