Performance evaluation of an analytical method to determine the Fc function in immunoglobulin concentrates produced at Laboratorio de Hemoderivados of the National University of Córdoba

Abstract

The main function of Immunoglobulin G (IgG) is to attack and eliminate any foreign antigen that has entered the body, and it is primarily responsible for humoral immunity. The IgG molecule is composed of two heavy chains and two light chains, linked together by disulfide bridges. Through enzymatic action, IgG can be cleaved into fragments: a Fab fragment, in which IgG binds to the antigen, and a crystallizable fragment, or Fc fragment. Since the latter mediates several biological mechanisms, such as complement system activation, it is crucial to determine its function in purified IgG concentrates used for replacement therapy. The European Pharmacopoeia (EP) describes an assay for evaluating Fc function based on the ability of IgG to bind to an antigen adsorbed to red blood cells (RBC) and produce its lysis through complement system activation. The objectives of this study were to evaluate the performance of the method described in EP through the parameters of precision, specificity, and accuracy, and to analyze IgG concentrates produced at the Laboratorio de Hemoderivados (LH) for intravenous and subcutaneous administration. The analysis of said parameters demonstrated that the evaluated analytical method has satisfactory performance in determining Fc function, ensuring the quality and efficacy of therapeutic concentrates. Additionally, the study concluded that differences in the production processes to obtain concentrations for intravenous or subcutaneous administration do not affect the functionality of the Fc fragment of IgG.