– Assistant Professor , UT Health San Antonio, United States
Aim: This study aimed to evaluate anti-HLA Class I antibody detection and assess HLA eplet patterns associated with platelet transfusion refractoriness (PTR) in Hispanic patients.
Methods: Single center retrospective study identified 16 Hispanic PTR patients for analysis. Platelet transfusion efficacy determined by corrected count increment (CCI) calculation and a CCI of < 5,000 was used to categorize patients as having PTR. Class I anti-HLA antibody testing was performed using the LABScreen Single Antigen (Thermo Fisher) assay. Baseline MFI values for each Class I HLA allele were summed to obtain additive HLA-A, HLA-B, HLA-C, and total additive MFI values. Additionally, Fusion-MatchMaker antibody verified eplets identified for alleles ≥1,000 MFI determined the additive Ellipro scores (Table 1). Statistical analysis included Spearman Rank Correlation, Jonckheere-Terpstra Test, Mann-Whiteney U Test and ROC analysis.
Results: Significant negative correlations were observed between CCI with total additive MFI (r = -0.656, p = 0.008) (Figure 1), allele specific MFI for HLA A*03:01 (r = -0.728, p = 0.002), C*14:02 (r = -0.795, p < 0.001), and C*01:02 (r = -0.727, p = 0.002) and cPRA (r = -.604, p =0.017). A significant positive correlation between MFI and cPRA (r = 0.944, p < 0.001) was observed (Figure 2). Analysis of cut-points yielded significance between negative and strong MFI for HLA B*07:02 (p =0.002). No significant difference was observed for additive antibody verified eplet Ellipro scores between patients with and without PTR (Figure 3). Further analysis by ROC yielded a fair area under the curve of 0.716 (95% CI, 0.302, 1.130), but the very broad confidence interval limits utility of additive Ellipro scoring for antibody verified eplets in this small sample size.
Conclusion: This study provides valuable insight into anti-HLA antibodies associated with PTR in Hispanic patients. Currently, there is no single parameter used to assess both antibody binding (MFI) and diversity. As additive MFI values increase, CCI values decrease, showing that diversity and binding of anti-HLA antibodies contribute to PTR in Hispanic patients. These results will contribute to development of a preliminary system of more complete immunologic compatibility evaluation in HLA antibody mediated PTR in Hispanic patients.
