HLA DRB1*01:02 allele is associated with anti-AT1R antibodies production in kidney transplanted patients.

BACKGROUND: Kidney transplantation is lifesaving treatment for end-stage renal disease, yet immune-mediated complications limit long-term graft survival. Non-HLA antibodies (NHLA), particularly anti-Angiotensin type 1 receptor antibodies (AT1R-abs), are emerging mediators of graft injury. This study investigated whether selective HLA alleles influence AT1R-ab development in kidney transplant recipients. MATERIAL AND METHODS: We analyzed a cohort of 59 kidney recipients carrying the HLA-A*33:01-B*14:02-DRB1*01:02 haplotype and 52 controls. Pre- and post-transplant sera were tested for donor-specific anti-HLA antibodies via Luminex-based single antigen bead assay and AT1R-ab via enzyme-linked immunosorbent assay and categorized as positive (≥17 U/mL), intermediate (10.1-16.9 U/mL) and negative (≤10 U/mL). In silico analysis were performed to assess peptide binding to HLA haplotypes. RESULTS: AT1R-abs were markedly enriched in the DR1 patients, both pre- (p = 0.0009) and post-transplant (p < 0.0001), at variance with controls, who were rarely positive. In silico prediction revealed that HLA-DRB1*01:02, typically the involved DRB1*01 subtype of the above-mentioned haplotype, can present AT1R peptides with greater binding affinity. CONCLUSIONS: These results suggest a possible genetic link between HLA haplotypes and AT1R-ab development in kidney transplant recipients, probably due to a higher binding affinity of some AT1R-derived peptides to HLA-DRB1*01:02. Understanding this association may enable personalized immunosuppressive therapies.