Immunochemical-based assays in the bioanalysis of immunoglobulins

Intravenous immunoglobulin (IVIG) preparations consist of IgG derived from a pool of human plasma of healthy individuals and have been used as routine treatment of patients with primary and secondary immunodeficiencies, autoi mmune, and/or inflammatory diseases. Emergence of new infectious agents and development of antibiotic resistance in many bacteria have posed serious p roblems in the treatment of infections. Since IVIGs contain natural antibod ies that occur in the healthy population, their administration to immunocom promised hosts either as a prophylactic agent or as complementary treatment to the usual antimicrobial treatment have been studied. Contradictory resu lts obtained by several clinical studies in respect to the clinical efficac y of IVIGs have in part been ascribed to the poor characterization of IVIG preparations in terms of their specific antibody content against the variou s pathogenic microorganisms. Immunoassays constitute a promising tool for b ioanalysis of IVIGs thanks to the high sensitivity, repeatability and ease of implementation. Ensuring high selectivity, enzyme immunoassays have been used for determination of the levels of pathogen-specific antibodies in IV IG preparations. In this review, the application of irnmunoassays monitorin g such specific antibodies in IVIGs and the relationship of estimated titer s with their in vitro opsonic activity are summarized. The relationship of the content of specific antibodies in IVIGs and their functional efficacy w ith the outcome of clinical studies including patients with primary immunod eficiencies and premature neonates treated with IVIGs is also discussed. (C ) 2000 Elsevier Science B.V. All rights reserved.