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.