IgG in factor VIII preparations was studied as a possible cause of adverse reactions following infusion of hemophiliacs. Thin-layer immuno-gel filtration analysis of nine products from seven firms demonstrated aggregated and monomeric IgG at highly variable amounts and proportions. These factor VIII products contained from 20 to 700 mg IgG per 1000 IU of factor VIII; IgG-fibrinogen complexes were demonstrated by doubleantibody testing. A relationship is suggested between aggregated IgG and/or IgG complexes in factor VIII concentrates and adverse clinical reactions. They may also partially explain abnormalities and aberrations of the immune system previously reported in hemophiliacs.

A γ-globulin preparation for intravenous use was given to 11 patients with antibody deficiency syndromes. Most of them had reacted earlier to intramuscular injections of normal γ-globulin. The γ-globulin employed produced adverse reactions, often quite severe in 8 of 9 intravenous infusions in three patients. After premedication with hydrocortisone, side effects appeared on 18 of 48 occasions in 10 patients, but only twice were they so severe that the infusions had to be interrupted. Thus, it seems that hydrocortisone diminishes the risk of side effects. The intravenously administered γ-globulin seemed to be just as effective as the preparations for intramuscular use, and no severe infections appeared during the period of observation. There was no indication that the single hydrocortisone injections, usually 200 mg, increased the risk of contracting infections, but still such medication should be used with great caution in antibody-deficient patients.