In vivo effects in mice of IVIG infusion on plasma levels of monoclonal antibodies that were continuously infused at a fixed rate.

A mixture of a mouse monoclonal IgG1 antibody to human C1 inhibitor (RII) and a mouse monoclonal IgA antibody to human IL-6 was continuously infused at a rate of 0.25 μL/h using an implanted osmotic pump. Infusion was started 4 days before IVIG administration, and at the beginning of the infusion an intravenous bolus dose of 35 μL per mouse was given to obtain a steady state plasma concentration more quickly. IVIG was given at a dose of 1.8 g/kg body weight at time zero. Plasma concentrations of the monoclonal antibodies are expressed as a percentage of their concentration in the infusate. Data represent mean ± SD (n = 6). **P < .01 compared with values at time zero (paired t test).