There are currently more than 100,000 patients in the United States awaiting kidney transplantation and 20% are sensitized to Human Leukocyte Antigen (HLA). HLA-sensitized patients who do not receive desensitization prior to transplantation are at high risk of graft loss due to acute and chronic antibody-mediated rejection after transplantation. Hence, in the recent decade, researchers have focused their attention on the development of better desensitization drugs. Many of these studies involve animal testing which is expensive, time-consuming and raises ethical concerns. The goal of our study was to investigate more rapid, less expensive, and more ethical ways of testing desensitization drugs on antibody-secreting cells (ASC). We used ELISpot, an in vitro method, to test five desensitization drugs on spleen cells harvested from a monkey who died of complications after kidney transplantation due to organ rejection. The drugs we tested were Carfilzomib (a proteasome inhibitor) and four monoclonal antibody drugs (Belatacept, 2C10, Tabalumab, and Daratumumab). We incubated the spleen cells with each drug on an ELISpot plate and quantified the ASC in each well. Spleen cells incubated with Carfilzomib had a significant decrease in spot size, indicating a reduction in antibody secretion. When the four monoclonal antibody drugs were each incubated with spleen cells, we detected countable spots in wells containing lower concentrations of drugs (1ng/mL-1ug/mL) but not higher concentrations (10ug/mL-100ug/mL). Furthermore, no significant reduction in spot size or number of spots compared to untreated controls was observed in the well plates treated with monoclonal antibody drugs. This result contradicts the results of in vivo studies demonstrating that the monoclonal antibody drugs reduce the number of ASC in vivo. However, in theory, we should have seen a reduction of ASC using ELISpot when treating ASC with these drugs. Therefore, we speculate that optimization of ELISpot testing on monoclonal antibody drugs would improve the outcomes. In vitro testing using ELISpot is a good alternative to in vivo tests of desensitization drugs for proteasome inhibitor drugs such as Carfilzomib but further work is required to optimize ELISpot testing on monoclonal antibody drugs. This method of screening desensitization drugs has great potential in the organ transplantation field to rapidly identify potential desensitization drugs, saving time, money, and animal lives.

Efficacy and efficiency of five desensitization drugs for the optimization of HLA incompatible kidney transplantation in vitro using ELIspot

2019 Spring National Meeting

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