81-P

Abstract

Aim Therapies exist for the bulk removal of antibodies in sensitized transplant patients, but there are no means to specifically deplete antibodies that recognize a specific HLA molecule. Current bulk antibody removal procedures may leave a patient compromised immunologically and more susceptible to opportunistic infections. The goal of this project was to create specific HLA-A∗02:01 removal matrices and demonstrate their ability to capture defined anti-HLA antibodies. Methods Soluble class I HLA-A∗02:01 molecules were produced in a native conformation in mammalian cells, purified by affinity chromatography, coupled to a Sepharose matrix, and loaded into a column enclosure. Various columns were created and tested with an automated chromatography system by initial injection of various HLA antibodies under different loading conditions. After an extensive column wash, the bound antibodies were released by a pH shift and quantitated. Loading and elution profiles were recorded. Results Initial tests show that HLA columns maintain their structural integrity and function. Multiple passes of the antibody W6/32, recognizing only intact HLA molecules, resulted in consistent and repeatable binding patterns. During the entire performance process, several parameters were identified, determining column saturation, capacity and efficiency values. Specificity was shown by removing a typical A∗02:01 recognition pattern from an A2 sera. In addition, treatment conditions were established to reuse the device. Conclusions Anti-HLA antibody removal devices are highly efficient in selectively depleting HLA antibodies. Capable of removing up to 1 mg per ml of matrix depending on the avidity of the antibody makes this device very efficient for research studies of HLA antibodies and provides promise for therapeutic applications. Furthermore, this device might also find an application in HLA diagnostics, allowing for the deconvolution of serologic samples and providing a new way to evaluate high PRA patients.