Suppression of Secondary Antibody Response by Intravenous Immunoglobulin in a Patient with Haemophilia B and Antibodies

A 39‐year‐old patient, suffering from severe haemophilia B and antibodies against factor IX, has twice been treated with extracorporeal protein A‐Sepharose adsorption followed by conventional substitution therapy in combination with immunosuppression (cyclophos‐phamide). On both occasions, separated by a 2‐year interval, the same procedure was followed except that, on the second, administration of i.v. immunoglobulin (Gammonativ, KabiVitrum) was added. Within a week of the first treatment the patient developed a 15‐fold increase in the antibody titre. Following the second treatment described here, no secondary antibody response could be detected, and after a further 12 weeks only traces of antibodies are demonstrable. It seems that antibody synthesis was suppressed by the i.v. immunoglobulin. No evidence was found to demonstrate that the effect was due either to a non‐specific suppression of the immune and reticuloendothelial systems or to the action of interfering antibodies. It has not yet been established whether or not the protein A‐Sepharose adsorption technique, or the immunosuppressive treatment, contributed in any way to the result. The observations suggest a new approach to the treatment of haemophiliacs with antibodies of the high‐responding type