IgG4 antibodies have a reduced affinity for C1q and therefore their anti-inflammatory activity is different from other IgG subclasses. IgG4 antibodies are known to actively swap their Fab arm with another molecule to produce a recombinant antibody with two different binding specificities. This exchange is thought to be an important biological mechanism contributing to its anti-inflammatory activity.IgG4 antibody is normally non-inflammatory, but autoreactive IgG4 antibody is known to be associated with immunoglobulin G4-related disease (IgG4-RD), which is characterized by lymphoplasmacytic infiltration and elevated serum IgG4.

Concentrations of ≥2.0 mg/ml