In order to assess compatibility between donors and recipients for organ transplantation, the recipient’s anti-HLA antibody profile is compared to the donor’s HLA typing. Determination of the recipient’s anti-HLA antibody profile is done through use of a single antigen bead assay. Unfortunately, false positive reactivity within the assay is one of its major limitations. While not as dangerous as a false negative, a false positive result can greatly reduce a recipient’s chances of receiving an organ. For example, a DRB4 false positive result in the MHC class II single antigen bead assay, a patient is considered non-compatible with 50% of the population. One of the primary ways false reactivity is identified is through surrogate flow cytometric crossmatching, where a donor expressing the antigen of interest is incubated with the recipient’s serum to see if a reaction occurs. While surrogate flow cytometric crossmatches are useful in determining the true reactivity of a recipient, finding an acceptable donor can often be difficult if the patient is highly sensitized. Therefore, it was hypothesized that a cell line expressing an MHC antigen of interest could be used in place of a surrogate donor. This study focused on using T2 cell lines expressing either DRB4 or DQA1*05:01/DQB1*02:01, two common MHC class II false positive results within the single antigen bead assay, as surrogate donors for a flow cytometric crossmatch. Results showed that the T2 cell line could be used as a surrogate donor. When compared to clinical surrogate crossmatches, the T2 cell line surrogate flow cytometric crossmatches showed concordance rates of 95% and 92% for DRB4 and DQA1*05:01/DQB1*02:01 respectively. In conclusion, it was determined that the T2 cell line could be used as a surrogate donor for ruling out false positive results in the single antigen bead assay. While further testing is still necessary, the success of this experiment opens the door for further investigation. It is likely that other MHC class II antigens could be transduced into the T2 cell line to rule out more false positive results, or another cell line could be used to allow MHC class I false positives to be ruled out. Overall, the success of this experiment shows promise for the future as new ways are found to improve patients’ chances of receiving a transplant, and improve overall outcomes in the field of transplantation.
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