Antigenic burden and serum IgG concentrations influence rituximab pharmacokinetics in rheumatoid arthritis patients.

The association between CD19+ count and k10 may be explained by target-mediated drug disposition, while the association between IgG serum concentration and k10 may be explained by a saturation of the neonatal Fc receptor at high IgG concentrations, resulting in decreased recycling of rituximab.