Theory of immunopathological processes caused by streptococci

In investigation of GAS receptor proteins for non-immune binding the Fc-fragment of immunoglobulin G allowed to put forward and substantiate a hypothesis of their initiating role in genesis of poststreptococcal diseases (glomerulonephritis and endocarditis).

 According to the hypothesis the binding of autologous IgG causes the development of immune inflammation at the expense of a number of consecutive events (induction of antibodies to autologous IgG, formation of immune complexes, synthesis of proinflammatory cytokins, tissue deposition of IgG-anti-IgG complexes and C3-complement), causing destructive-degenerative lesion of the kidney and heart tissues.  

First evidences of it were obtained in genetic experiments with isogenic IgG Fc-mutants of GAS defective by this marker. This conclusion is not at variance with the idea of participation of cross-reacting antigens of the microbe and "host" in this process, but assign them a part of the factor maintaining but not triggering the process.