Table 1.

The differences between IgG1−, IgG3−, and IgG4-mediated autoimmune disease.

IgG1 and IgG3	IgG4
Antigens are receptors, ion channels, or multisubunit proteins	Antigens are typically not receptors, ion channels, or multisubunit proteins
Pathomechanism requires complement and immune cell–mediated cytotoxicity and inflammation	Pathomechanism is blocking of essential protein–protein interactions
Structural damage to target tissue	No structural damage to target tissue
Crosslinking and internalization of the antigen	Monovalent antigen binding, no crosslinking
Sometimes associated with paraneoplastic events	No clear tumor association
Result from TH1-related cytokine expression	Result from TH2-related cytokine expression