Intravenous immunoglobulin-induced panel reactive antibody A reduction: Not all preparations are created equal

Use of intravenous (IV) immunoglobulin (Ig) to obtain panel reactive antibody (PRA) A reduction in sensitized patients has been widely reported. Because no IVIg preparation is formulated specifically for this purpose, the authors have sought to determine whether, through laboratory testing, they could guide the rational choice of product for clinical use. Using a flow cytometric approach, the authors have quantitatively determined the capacity of 22 different IVIg preparations to cause PRA reduction. IVIg preparations showed considerable variability in their individual capacity to reduce serum PRA. Protein-A pretreatment of IVIg preparations was found to reduce their capacity to cause PRA reduction. Laboratory screening of IVIg preparations provides a rational basis for the selection of product for administration to patients in whom the aim is to produce a PRA reduction. Experiments involving protein-A treatment of IVIg preparations indicate that immunoglobulin G is the principal factor involved in the abrogation of serum reactivity.