An enzyme immunoassay to determine the levels of specific antibodies toward bacterial surface antigens in human immunoglobulin preparations and bloodserum

Human polyvalent intravenous immunoglobulin (IVIG) preparations are used as a complementary aid to the proper antimicrobial treatment of severely sept ic patients in intensive care units (ICUs) and/or as a prophylactic agent t o immunocompromized hosts, particularly prone to bacterial infections. Ther e is skepticism about the usefulness of IVIGs since it is not known whether their administration ensures the enhancement of humoral immune responses b y providing a sufficient amount of specific antibodies towards the specifie d bacterial pathogen to be treated. In this report, a simple and reproducib le enzyme-linked immunosorbent assay for determining the content of specifi c antibodies against bacterial surface antigens in commercially available I VIG preparations is described. The method is also easily applied to determi ne the amount of bacterial antibodies in blood serum. The levels of specifi c antibodies toward Gram positive and negative pathogenic isolates often en countered in ICUs were estimated in two IVIG (Sandoglobulin(R) and Gamimmun e(R)) preparations. Significant differences regarding the content of antibo dies to certain clinically bacterial isolates were identified not only betw een the two IVIG preparations tested, but also among various lots from each IVIG preparation. No significant variation (P less than or equal to 0.001) among the bottles derived from the same lot was determined in both prepara tions. The variation in the levels of specific antibodies in IVIG preparati ons may be attributed to differences between the donor pools as well as the manufacturing procedure. Application of the method to patients with primar y immune deficiencies showed that infusion of highly reactive IVIG preparat ions enhanced significantly their humoral response toward various pathogens . The results of this study suggest that the content determination of patho gen-specific antibodies in IVIG preparations before administration may be o f great importance for treating bacterial infections. (C) 1999 Elsevier Sci ence B.V. All rights reserved.