Characterization of the novel HLA-A*31:01:53 allele by next generation sequencing in a Chinese individual.

HLA-A*31:01:53 differs from HLA-A*31:01:02:01 by one nucleotide change at nucleotide 900 in exon 5 from G to A.

Single Nucleotide Variants as Proxies for HLA-A*31:01 in Native American Populations.

Carbamazepine triggers dermatologic hypersensitivity reactions, associated with specific human leukocyte antigens (HLAs), especially HLA-B*15:02 and HLA-A*31:01. Previous efforts to identify single nucleotide variants (SNVs) with high predictive value as HLA proxies, revealed that rs1061235 and rs17179220 fulfill these requirements for HLA-A*31:01 in some but not all populations. Herein we explored the predictive performance of rs1061235 and rs17179220 as HLA-A*31:01 tags in populations of Native American ancestry, which are largely underrepresented in pharmacogenomic studies. The study cohorts comprised the overall Admixed American superpopulation of the 1000 Genomes Project (1 KG_AMR), a subcohort of individuals with predominant Native American ancestry (1 KG_NAT), the Native American population of the Human Genome Diversity Project (HGDP), plus Kaingang (KRC) and Guarani (GRC and GKW) adults from indigenous reservation areas in Brazil. The diversity of cohorts is reflected in the range of frequencies of HLA-A*31:01 (0.02-0.65), rs1061235 (0.03-0.13) and rs17179220 (0.12-0.66), as well as in the predictive performance of these SNVs as HLA-A*31:01 proxies. NPV (negative predictive value), the metric of primary interest for pharmacogenetic-informed carbamazepine prescription was maximal (NPV = 1.0) for both SNVs in 1 KG_AMR and 1 KG_NAT, for rs17179220, but not rs1061235 (NPV = 0.91) in HGDP, and for rs17179220 in GWK, but not GRC (NPV = 0.88) or KRC (NPV = 0.80). Collectively, the data support the notion that rs1061235 and rs17179220 are not optimal proxies for HLA-A*31:01 across populations of Native American ancestry.

In silico study of the association of the HLA-A*31:01 allele (human leucocyte antigen allele 31:01) with neuroantigenic epitopes of PLP (proteolipid protein), MBP (myelin basic protein) and MOG proteins (myelin oligodendrocyte glycoprotein) for studying the multiple sclerosis disease pathogenesis.

The main pathologic hallmark of multiple sclerosis is a demyelinating plaque that contains a prominent immunologic response dominated by T cells of the immune system. PLP (proteolipid protein), MPB (myelin basic protein), and Myelin oligodendrocyte glycoprotein (MOG) proteins are important autoantigens for the demyelinating of CNS in multiple sclerosis. There is good evidence indicating that T CD8+ cells and MHC class I molecules play an important role in this disease. The HLA-A*31:01 allele of MHC class I is a member of HLA-A3 superfamily and there is no clear report concerning the relationship of this allele with MS. Feeling this gap, we studied the possible association of the HLA-A*31:01 with MS by prediction of neuroantigenic epitopes of human MBP, PLP, and MOG proteins of myelin sheath using in silico methods. PLP did not show any neuroantigenic epitope, but the two epitopes of MBP and seven epitopes of MOG for HLA-A*31:01 were determined via bioinformatics servers. In silico study of the nine epitope showed that MOG195-204 (LIICYNWLHR) peptide of the membrane-associated/cytoplasmic part of human MOG has suitable binding affinity to the HLA-A*31:01 allele as a potential neuroantigenic epitope. Further investigations of this peptide revealed that the binding of C-terminal residue of this peptide has a more significant effect on binding to this allele than the N-terminal part of the peptide. Altogether, this combination of "LIICYNWLHR/A*31:01 allele "may play an important role in MS pathogenesis and this complex is suggested for further studies such as T cell receptor.Communicated by Ramaswamy H. Sarma.

Characterization of the novel HLA-A*31:01:34 allele by polymerase chain reaction sequencing-based typing.

HLA-A*31:01:34 differs from HLA-A*31:01:02:01 by one nucleotide substitution at position 123 C>G.

The Mechanistic Differences in HLA-Associated Carbamazepine Hypersensitivity.

Drug hypersensitivity reactions that resemble acute immune reactions are linked to certain human leucocyte antigen (HLA) alleles. Severe and life-threatening Stevens Johnson Syndrome and Toxic Epidermal Necrolysis following treatment with the antiepileptic and psychotropic drug Carbamazepine are associated with HLA-B*15:02; whereas carriers of HLA-A*31:01 develop milder symptoms. It is not understood how these immunogenic differences emerge genotype-specific. For HLA-B*15:02 an altered peptide presentation has been described following exposure to the main metabolite of carbamazepine that is binding to certain amino acids in the F pocket of the HLA molecule. The difference in the molecular mechanism of these diseases has not been comprehensively analyzed, yet; and is addressed in this study. Soluble HLA-technology was utilized to examine peptide presentation of HLA-A*31:01 in presence and absence of carbamazepine and its main metabolite and to examine the mode of peptide loading. Proteome analysis of drug-treated and untreated cells was performed. Alterations in sA*31:01-presented peptides after treatment with carbamazepine revealed different half-life times of peptide-HLA- or peptide-drug-HLA complexes. Together with observed changes in the proteome elicited through carbamazepine or its metabolite these results illustrate the mechanistic differences in carbamazepine hypersensitivity for HLA-A*31:01 or B*15:02 patients and constitute the bridge between pharmacology and pharmacogenetics for personalized therapeutics.

Single-tube multiplex real-time PCR assay for rapid and reliable detection of HLA-A*31:01 allele.

AIM: HLA-A*31:01 has been associated with carbamazepine-induced hypersensitivity reactions. HLA-A*31:01 genetic testing is recommended before the initiation of carbamazepine therapy. METHODS: A novel real-time PCR assay was designed for HLA-A*31:01 detection by allele-specific primers and TaqMan minor groove binding probes. RESULTS: The genotyping results in 100 subjects by the established method who were in 100% agreement with the sequencing-based typing method. The assay presents a sensitivity of 1 (95% CI: 0.69-1.00), a specificity of 1 (95% CI: 0.96-1.00) and a positive and negative predictive value of 1. The carrier rates of HLA-A*31:01 in Tibetan (n = 45), Han Chinese (n = 100), Miaos (n = 48) and Khalkhas (n = 48) were 22.2, 10, 4.2 and 18.8%, respectively. CONCLUSION: This assay is reliable to detect HLA-A*31:01 and would be useful to prevent carbamazepine-induced hypersensitivity reactions.

Association between HLA gene polymorphism and cutaneous adverse reactions caused by antiepileptic drugs.

The association between cutaneous adverse drug reactions (cADRs) caused by antiepileptic drugs (AEDs) and human leukocyte antigen-A (HLA-A) and HLA-B genes in Chinese Han population in Shanghai was investigated. Through the case-control study, 30 child patients with AED-induced cADRs (cADRs group), 60 AED-tolerant child patients (AED-tolerant group) and 60 normal children not taking AEDs (normal group) were collected. The HLA-B*15:02 and HLA-A*31:01 genotypes were detected using the polymerase chain reaction-sequence-specific oligonucleotide (PCR-SSO) probe method, and the correlation of HLA-B*15:02 and HLA-A*31:01 genes with the incidence of cADRs was analyzed. The positive rate of HLA-B*15:02 gene was 83.33% in the cADRs group, which was significantly increased compared with that in the AED-tolerant and normal groups (P<0.01). The positive rate of HLA-A*31:01 gene was 63.33% in the cADRs group, which was obviously increased compared with that in the AED-tolerant and normal groups (P<0.01). There were no significant differences in HLA-B*15:02 and HLA-A*31:01 genotypes between the AED-tolerant and normal groups (P>0.05). The results showed that HLA-B*15:02 and HLA-A*31:01 are significantly associated with cADRs in a Chinese Han population in Shanghai, suggesting that HLA-B*15:02 and HLA-A*31:01 genotypes should be detected in the application of AEDs.

Genetic risk factors for antiepileptic drug-induced hypersensitivity reactions in Israeli populations.

The human leukocyte antigen (HLA) alleles B*15:02 and A*31:01 have been identified as predictive markers of adverse cutaneous effects of carbamazepine and phenytoin in Asian and North European populations, respectively. Our aim was to estimate the distribution of these alleles in Jewish and Arab populations in Israel. The HLA-B*15:02 and HLA-A*31:01 carrier rate was estimated based on data from the Hadassah Bone Marrow Registry. Data on Stevens-Johnson syndrome (SJS)- and toxic epidermal necrolysis (TEN)-related hospitalizations were obtained from the Israeli Ministry of Health (MOH) registries and from four Israeli medical centers. Of 83,705 Jewish and Arab-Muslim donors, 81 individuals of known origin carried the HLA-B*15:02. Among them, 66 were Jews of India-Cochin descent. Of the Cochin Jewish donors, 12.7% were B*15:02 carriers. HLA-A*31:01 carrier incidence among Arab and Jewish Israeli populations (3.5% and 2.2%, respectively) was within the range reported in other countries. We did not identify SJS- or TEN-related hospitalizations of Jews of Indian descent. Yet, this population should be considered at greater risk for antiepileptic drug-induced SJS and TEN. Until further data on actual risk are available, such patients should be typed for HLA-B before treatment with carbamazepine or phenytoin.

Pharmacogenetic testing prior to carbamazepine treatment of epilepsy: patients' and physicians' preferences for testing and service delivery.

AIM: Pharmacogenetic studies have identified the presence of the HLA-A*31:01 allele as a predictor of cutaneous adverse drugs reactions (ADRs) to carbamazepine. This study aimed to ascertain the preferences of patients and clinicians to inform carbamazepine pharmacogenetic testing services. METHODS: Attributes of importance to people with epilepsy and neurologists were identified through interviews and from published sources. Discrete choice experiments (DCEs) were conducted in 82 people with epilepsy and 83 neurologists. Random-effects logit regression models were used to determine the importance of the attributes and direction of effect. RESULTS: In the patient DCE, all attributes (seizure remission, reduction in seizure frequency, memory problems, skin rash and rare, severe ADRs) were significant. The estimated utility of testing was greater, at 0.52 (95% CI 0.19, 1.00) than not testing at 0.33 (95% CI -0.07, 0.81). In the physician DCE, cost, inclusion in the British National Formulary, coverage, negative predictive value (NPV) and positive predictive value (PPV) were significant. Marginal rates of substitution indicated that neurologists were willing to pay £5.87 for a 1 percentage point increase in NPV and £3.99 for a 1 percentage point increase in PPV. CONCLUSION: The inclusion of both patients' and clinicians' perspectives represents an important contribution to the understanding of preferences towards pharmacogenetic testing prior to initiating carbamazepine. Both groups identified different attributes but had generally consistent preferences. Patients' acceptance of a decrease in treatment benefit for a reduced chance of severe ADRs adds support for the implementation of HLA-A*31:01 testing in routine practice.