The Association of Pre-Transplant Mixed Lymphocyte Reaction (MLR) with the Function of the Kidney Allograft and Antibody Response

Aim The mixed lymphocyte reaction (MLR) is a critical assay for evaluating immunological compatibility between donors and recipients prior to transplantation. Purpose This prospective study aimed to evaluate the association of the renal allograft function with outcomes of the pre-transplant carboxyfluorescein diacetate succinimidyl ester (CFSE)-MLR assay and the levels of donor-specific antibodies (DSAs). Patients and Methods The study included 14 live donors and non-sensitized recipient pairs. Peripheral blood samples were collected from donor and recipient pairs, and then peripheral blood mononuclear cells (PBMCs) were isolated. Donor cells were treated with Mitomycin-C as inactivated stimulators, and recipient PBMCs were labeled with CFSE as responder cells for flow cytometric analysis of the responder cell proliferation. Post-transplant renal function was monitored by serial measurements of serum creatinine levels, which were then correlated with MLR proliferation rates. Additionally, the relationship between pre-transplant MLR proliferation and DSA titers was examined. Correlative analyses were also performed between MLR outcomes and DSA levels, as well as the panel reactive antibody (PRA) outcomes. Results Significant increases in the percentage of proliferating responder cells were observed at days 3 and 5 relative to baseline (day 0). A positive correlation was identified between day 5 proliferation rates and PRA Class II levels. Pre-transplant cellular proliferation did not significantly correlate with serum DSA titers measured at six months post-transplant. Conversely, a statistically significant positive correlation was detected between day 5 MLR proliferation and serum creatinine levels at six months post-transplantation. Conclusion The CFSE-MLR assay represents a reliable association with post-transplant immunological status and allograft function. Nevertheless, further evidence-based research with larger cohorts is warranted to validate these findings and strengthen their clinical applicability.