Monitoring of two intravenous immunoglobulin preparations for immunoglobulin G subclasses and specific antibodies to bacterial surface antigens and relation with their levels in treated immunodeficient patients

Patients with antibody deficiency disorders are highly susceptible to bacte rial infections. Replacement therapy with intravenous immunoglobulin prepar ations (IVIG) has been established in such patients for two decades. The ef ficacy of IVIG treatment depends on the amount of functional pathogen-speci fic antibodies provided. The present study was undertaken to determine the levels of immunoglobulin classes, IgG subclasses, and specific antibodies t o bacterial surface antigens in two different IVIG preparations (Sandoglobu lin(R) and Gamimmune(R)) and blood sera of IVIG-treated immunodeficient pat ients. The levels of IgG, IgA, IgM and IgG subclasses were determined in bo th IVIG preparations and in patients' sera and were compared with those of healthy individuals. Sandoglobulin(R) contained significantly higher concen trations of IgA, IgG(2) and IgG(4) than Gamimmune(R). The latter contained higher concentrations of IgG(1). Patients treated with Gamimmune(R) had sig nificantly lower concentration of IgG(4) as compared with healthy individua ls and Sandoglobulin(R)-treated patients. This finding was related to the p reparation's composition. Screening of 20 lots from each preparation for an tibodies to frequent clinically isolated strains of Escherichia coil, Staph ylococcus aureus, S. epidermidis, Klebsiella pneumoniae and Enterococci spp . showed a high lot-to-lot variability. In order to overcome the lot-to-lot variability and correlate the observed effects with each IVIG preparation, the administered IVIG lots were selected so that their titers were in the interval of mean value +/- S.D. for each pathogen. The two tested preparati ons showed significant differences in their content of specific antibodies that ultimately affected the levels of these antibodies in treated patients . More specifically, Sandoglobulin(R) contained higher levels of antibodies to E. roll and S. epidermidis strains. Infusion of this preparation mainta ined the respective antibodies in the recipients significantly higher than those of healthy individuals. Gamimmune(R) infusion led to similar and comp arable levels. Both IVIG preparations had comparable antibody titers reward s K. pneumoniae. provided high amounts of antibodies, and kept recipients' specific IgG at levels significantly higher than those of the healthy indiv iduals. Enterococci spp. specific antibodies were significantly higher in G amimmune(R), whereas titers of antibodies rewards S. aureus were comparable . Levels of antibodies against both Enterococci spp. and S. epidermis after administration of both preparations were close to those in healthy individ uals. None of the patients developed infection during the time of the study . In conclusion. most of the lots of the two IVIG preparations studied, des pite some quantitative differences. provide patients with sufficient amount s of antibodies to bacterial surface antigens that protect them against inf ections. (C) 2000 Elsevier Science B.V. All rights reserved.