The Importance of New Generation Sequencing (NGS) HLA Typing in Renal Transplantation—Preliminary Report

Abstract

IntroductionThanks to new generation sequencing (NGS) and expansion of HLA typing with additional loci, it will be possible to increase the effectiveness of graft survival and to avoid complications related to the immune system. New pharmacogenetic factors are still being researched to develop better immunosuppressive treatment. Material and methodsThe incidence of polymorphic HLA loci variants was established, based on a high-resolution NGS method in kidney graft recipients. Furthermore, haplotypic analysis between examined loci was conducted to type additional loci that may influence the transplantation result. A total of 120 kidney recipients were enrolled in the study. A commercial DNA extraction kit in Tubes (QIAamp DNA Blood Mini Kit Qiagen, Germany) was used to isolate DNA from the blood. Sequencing library preparation was done with TruSight HLA set. The Conexio computer program was used to analyse the results of HLA typing. ResultsThe patients with alleles A*02:01:01, B*44:02:01, C*03:03:01, C*01:02:01, C*05:01:01, C*07:02:01, DQB1*03:03:02, DQB1*06:04:01, or with haplotypic variation A*25:01:01-B*18:01:01- C*15:01:01 were taking the highest doses of cyclosporine (CsA), in contrast to patients with allele B*18:01:01, DQB1*06:02:01, DQB1*02:02:01, or haplotypic variation A*02:01:01- B*44:02:01-C*01:01:01, who were taking the lowest doses. The highest dose of tacrolimus (TAC) was administered to patients with alleles A*68:01:02, A*29:01:01, B*07:02:01, B*35:02:01, B*38:01:01, DRB1*12:01:01, DQB1*05:03:01, or haplotypic variations A*02:01:01-B*57:01:01-C*07:01:01, A*03:01:01-B*07:02:01-C*13:01:01, A*29:02:01-B*44:03:01- C*07:01:01, and A*01:01:01-B*08:01:01-C*03:01:01. Additionally, it was established that HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DPA1, and HLA-DQA1 show very slight polymorphism, which suggests that there is no need for their typing for transplantation purposes. Moreover, loci HLA-C, HLA-DQB1, and HLA-DPB1, which are not routinely examined in recipient-donor matching, show genetic variability that may increase the risk of transplant rejection or shortened graft life. ConclusionsExpanding the qualification procedure to include allele genotyping could allow clinicians to establish immunosuppressive treatment schemes that would be optimally suited for recipients' phenotype.