Impact of pre-transplant donor specific antibodies detected by Luminex with negative microlymphocytotoxicity assay and flow crossmatch in live-related renal transplant recipients.

INTRODUCTION/AIM: The Luminex assay, where beads are coated with a single HLA antigen, has been shown to detect HLA antibodies with more sensitivity and specificity as compared to microlymphocytotoxicity (CDC) assay and flow cross match (FCXM). We report the impact of low Mean Flourescence intensity (MFI) pre-transplant DSA by Luminex with negative CDC and FCXM on acute rejection, graft function, and survival.

METHODS

In this retrospective study between January 2015 to December 2021, 45 recipients had pre-transplant anti-HLA donor-specific antibodies (DSAs) detected by Luminex. Two control groups of 45 patients each matched for age and gender, first with non-DSA HLA antibodies and second with no antibodies by Luminex were selected to compare outcomes with DSA group.

RESULTS

In the DSA group of 45, 22 (48.8%) had class I (MFI mean 4043 ± 1909, range: 1096-7111), 20 (44.4%) class II (MFI mean 3601 ± 2310, range: 1031-9259), and 3 (6.6%) both class I (MFI mean 4746 ± 1922) and class II (MFI mean 3940 ± 2312) antibodies. Acute rejection episodes were reported in 15.6%, DSA group, 17.8% in non-DSA, and 24.4% in no antibody group (p = .538). Death censored graft survival at 1 and 5 years was 98% and 93% in DSA group, 100% and 95% in non-DSA and 93% and 85% in the no antibody group (p = .254).

CONCLUSIONS

Patients with low MFI DSA pre-transplant, with a negative CDC and FCXM under ATG induction, have similar graft outcomes at 1 and 5 years when compared to non-DSA and no antibody groups.