Comparative Assessment of Anti-HLA Antibodies Using Two Commercially Available Luminex-Based Assays.

Background: Allospecific anti-HLA antibodies (Abs) are associated with rejection of solid organ grafts. The 2 main kits to detect anti-HLA Ab in patient serum are commercialized by Immucor and One Lambda/ThermoFisher. We sought to compare the performance of both platforms.

Methods: Background-adjusted mean fluorescence intensity (MFI) values were used from both platforms to compare sera collected from 125 pretransplant and posttransplant heart and lung transplant recipients.

Results: Most HLA class I (94.5%) and HLA class II (89%) Abs with moderate to high MFI titer (≥4000) were detected by both assays. A modest correlation was observed between MFI values obtained from the 2 assays for both class I ( = 0.3, = 0.09, < 0.0001) and class II Ab ( = 0.707, = 0.5, < 0.0001). Both assays detected anti-class I and II Ab that the other did not; however, no specific HLA allele was detected preferentially by either of the 2 assays. For a limited number of discrepant sera, dilution resulted in comparable reactivity profiles between the 2 platforms.

Conclusions: Immucor and One Lambda/ThermoFisher assays have a similar, albeit nonidentical, ability to detect anti-HLA Ab. Although the correlation between the assays was present, significant variances exist, some of which can be explained by a dilution-sensitive "prozone" effect.