Description
IgG4 is the least abundant subclass, representing less than 4% of total IgG in the blood.
IgG4 is unique in its functional characteristics. Unlike other subclasses, IgG4 has limited ability to activate the complement system, making it less inflammatory. Instead, it plays a role in regulating immune responses, particularly in chronic antigen exposure (e.g., allergies). Over time, repeated exposure to certain antigens, such as allergens, leads to an increase in IgG4, which can dampen the allergic response.
IgG subclasses can also be ordered collectively: IgG subclasses (IgG1, IgG2, IgG3, IgG4)