Specific Human Leukocyte Antigen Research Articles

Deciphering the Genetic Landscape: Exploring the Relationship Between HLA-DQA1, HLA-DQB1, and HLA-DRB1 Genes in Diabetes Mellitus

Abstract: Diabetes mellitus (DM) is a complex and multifactorial metabolic disorder with a significant genetic component. The human leukocyte antigen (HLA) genes, specifically HLA-DQA1, HLA-DQB1, and HLA-DRB1, have been implicated in the susceptibility and pathogenesis of DM. This review delves into the intricate interplay of these HLA genes, seeking to unravel the genetic tapestry that contributes to the development and progression of diabetes. We begin by providing an overview of the HLA system and its critical role in immune regulation. Subsequently, we explore the current state of knowledge regarding the association between HLA-DQA1, HLA-DQB1, and HLADRB1 polymorphisms and susceptibility to both type 1 and type 2 diabetes. Emphasis is placed on recent advancements in genetic research methodologies, including genomewide association studies and next-generation sequencing, that have provided deeper insights into the genetic architecture of DM. The review also scrutinizes the functional implications of specific HLA alleles in modulating immune responses and the potential mechanisms by which they contribute to the autoimmune processes observed in type 1 diabetes. Additionally, we examine the role of HLA genes in the context of insulin resistance and beta-cell dysfunction in type 2 diabetes, shedding light on the shared and distinct genetic underpinnings of these two major forms of DM. Furthermore, we discuss the clinical implications of HLA genotyping in predicting disease risk, prognosis, and personalized treatment strategies. The integration of genetic information into clinical practice holds promise for precision medicine approaches in diabetes management.

In Silico Identification of Peanut Peptides Suitable for Allergy Immunotherapy in HLA-DRB1*03:01-Restricted Patients.

Peanut allergy, a prevalent and potentially severe condition affecting millions worldwide, has been linked to specific human leukocyte antigens (HLAs), suggesting increased susceptibility. Employing an immunoinformatic strategy, we developed a "logo model" based on amino acid frequencies in the peptide binding core and used it to predict peptides originating from 28 known peanut allergens binding to HLA-DRB1*03:01, one of the susceptibility alleles. These peptides hold promise for immunotherapy in HLA-DRB1*03:01 carriers, offering reduced allergenicity compared to whole proteins. By targeting essential epitopes, immunotherapy can modulate immune responses with minimal risk of severe reactions. This precise approach could induce immune tolerance with fewer adverse effects, presenting a safer and more effective treatment for peanut allergy and other allergic conditions.

Association of HLA alleles with cephalosporin allergy in the Taiwanese population

Cephalosporin antibiotics are widely used in clinical settings, but they can cause hypersensitivity reactions, which may be influenced by genetic factors such as the expression of Human leukocyte antigen (HLA) molecules. This study aimed to investigate whether specific HLA alleles were associated with an increased risk of adverse reactions to cephalosporins among individuals in the Taiwanese population. This retrospective case–control study analyzed data from the Taiwan Precision Medicine Initiative (TPMI) on 27,933 individuals who received cephalosporin exposure and had HLA allele genotyping information available. Using logistic regression analyses, we examined the associations between HLA genotypes, comorbidities, allergy risk, and severity. Among the study population, 278 individuals had cephalosporin allergy and 2780 were in the control group. Our results indicated that certain HLA alleles, including HLA-B*55:02 (OR = 1.76, 95% CI 1.18–2.61, p = 0.005), HLA-C*01:02 (OR = 1.36, 95% CI 1.05–1.77, p = 0.018), and HLA-DQB1*06:09 (OR = 2.58, 95% CI 1.62–4.12, p < 0.001), were significantly associated with an increased risk of cephalosporin allergy reactions. Additionally, the HLA-C*01:02 allele genotype was significantly associated with a higher risk of severe allergy (OR = 2.33, 95% CI 1.05–5.15, p = 0.04). This study identified significant associations between HLA alleles and an increased risk of cephalosporin allergy, which can aid in early detection and prediction of adverse drug reactions to cephalosporins. Furthermore, our study highlights the importance of HLA typing in drug safety and expanding our knowledge of drug hypersensitivity syndromes.

HLA Genotyping in Children With Celiac Disease Allows to Establish the Risk of Developing Type 1 Diabetes.

Celiac disease (CD) and type 1 diabetes (T1D) often co-occur and share genetic components in the human leukocyte antigen (HLA) class II region. We aimed to study the usefulness of HLA genotyping in predicting the risk of developing T1D in patients with CD and the temporal relationship between these diseases. A cohort of 1,886 Sardinian patients, including 822 with CD, 1,064 with T1D, and 627 controls, underwent HLA class II typing. Seventy-six of 822 patients with CD were also affected by T1D (CD-T1D), and their HLA genotypes were analyzed for specific HLA associations with CD, T1D, and controls. High-risk HLA-DQ genotypes, including HLA-DQ2.5/DQ8, -DQ2.5/DQ2.5, and -DQ2.5/DQ2.3, were strongly associated with CD-T1D with frequencies of 34.5%, 15.9%, and 18.8%, respectively. Conversely, certain HLA genotypes associated with CD seemed to confer protection against T1D development. Therefore, HLA genotyping allows for the identification of those patients with CD who might develop T1D. The frequency of patients with CD preceding T1D is higher in younger children than older ones, with implications for the early childhood approach to diabetes prevention. CD is a condition for future T1D development, and specific HLA genotypes can predict this risk. Early screening for celiac autoimmunity and subsequent HLA typing in CD children could help identify those at high risk of T1D, allowing for proactive interventions and immunotherapies to preserve β-cell function. These findings may support the re-evaluation of HLA typing in children with CD.

HLA investigation in ICI-induced T1D and isolated ACTH deficiency including meta-analysis.

Widespread use of immune checkpoint inhibitors (ICIs) in cancer treatment has led to an increase in the number of reported cases of immunotherapy-related endocrinopathies. This study aimed to analyze and compare human leukocyte antigen (HLA) signatures associated with ICI-induced type 1 diabetes (ICI-T1D) and isolated adrenocorticotropic hormone deficiency (ICI-IAD) in patients with both conditions. HLA signatures were examined for their frequencies of occurrence in 22 patients with ICI-T1D without concurrent IAD, including 16 patients from nationwide reports (ICI-T1D group) and 14 patients with ICI-IAD without concurrent T1D (ICI-IAD group). The HLA signatures were also compared for their respective frequencies in 11 patients with ICI-T1D and ICI-IAD, including eight from nationwide reports (ICI-T1D/IAD group). In the ICI-T1D group, HLA-DRB1*09:01-DQB1*03:03 and DQA1*03:02, which are in linkage disequilibrium with DRB1*09:01-DQB1*03:03 and DRB1*13:02-DQB1*06:04, were susceptible to ICI-T1D, whereas DRB1*15:02-DQB1*06:01 was protective against ICI-T1D. In the ICI-IAD group, DPB1*09:01, C*12:02-B*52:01, and DRB1*15:02-DRB1*06:01, which are in strong linkage disequilibrium, were associated with susceptibility to ICI-IAD. Moreover, DRB1*15:02-DRB1*06:01 was not detected in the ICI-T1D/IAD group. This study revealed specific HLA signatures associated with ICI-T1D and ICI-IAD. Moreover, HLA-DRB1*15:02-DRB1*06:01, an ICI-IAD-susceptible HLA haplotype, coincides with the ICI-T1D-protective HLA haplotype, suggesting that the presence of DRB1*15:02-DRB1*06:01 may protect against the co-occurrence of T1D in patients with ICI-IAD.

Association between specific human leukocyte antigen alleles and development of thyroid immune-related adverse event.

Aim: Inherent variations in human leukocyte antigen (HLA) alleles have been revealed epidemiologically to influence the development of autoimmune diseases. HLA alleles may thus also be associated with the development of immune-related adverse events (irAEs), such as thyroid irAE. Materials & methods: In this case-control study, 71 cancer patients who received immune checkpoint inhibitors were enrolled and HLA-genotyped and the frequency of HLA alleles was compared. Results: A*26:01, DPA1*01:03 and DPB1*02:01 were significantly more frequent in patients with thyroid irAE than in patients without any irAEs (35.0 vs3.2% [p=0.004], 80.0 vs45.2% [p=0.020] and 55.0 vs25.8% [p=0.044], respectively). Conclusion: A*26:01, DPA1*01:03 and DPB1*02:01 appear to be associated with thyroid irAE.

An exploratory study on prediction of risk for abemaciclib-induced interstitial lung disease or hepatotoxicity by specific human leukocyte antigen alleles.

3087 Background: Interstitial lung disease (ILD) and hepatotoxicity have been observed in a small population of patients treated with abemaciclib. It has been reported that the antitumor effect of cyclin-dependent kinases 4 and 6 inhibitors including abemaciclib is contributed by not only inducing tumor cell cycle arrest but also promoting antitumor immunity. Based on our experience of higher incidence of severe toxicities in the clinical study of abemaciclib combined with nivolumab, we speculated that abemaciclib-related toxicity might also be mediated by immune system. This study sought to identify specific human leukocyte antigen (HLA) alleles associated with abemaciclib-induced ILD or hepatotoxicity. Methods: Of 236 abemaciclib-treated patients with advanced breast cancer in the previous observational study, 83 patients were enrolled by obtaining additional informed consent for collecting blood and pharmacogenetic investigation. Genomic DNA was extracted from peripheral whole blood, and HLA-A, -B, -C, -DRB1, -DQA1, -DQB1, and -DPB1were genotyped to four-digit resolution by next generation sequencing method. Exploratory marker identification evaluated the HLA alleles with frequency of ≥ 10% in cases. The significance level was adjusted by Bonferroni’s correction for multiple testing. Results: One hundred seventeen alleles ( HLA-A,13 alleles; -B, 26 alleles; -C, 16alleles; -DRB1,24 alleles; -DQA1, 14 alleles; -DQB1, 13 alleles; -DPB1, 11 alleles) were detected. Of 28 alleles with frequency of ≥ 10% in cases with development of ILD [significance level = .00178 (0.05 divided by 28)], there was no significant association between HLA allele carriages and development of ILD in 16 cases and 67 controls. Of 28 alleles with frequency of ≥ 10% in cases with grade ≥ 2 alanine aminotransferase (ALT) elevation [significance level = .00178 (0.05 divided by 28)], HLA-DQA1*05:05 allele carriage was found to be significantly associated with ALT elevation in 13 cases with grade ≥ 2 and 47 controls with grade 0. HLA- DQA1*05:05 was present in 30.8% of cases and in 0.0% of controls ( P=.00147; odds ratio, 45.0; 95% CI, 2.23 to 907). Suggestive associations of ALT elevation were observed with HLA-DPB1*05:01 allele carriage ( P=.00930; odds ratio, 11.5; 95% CI, 1.38 to 95.7) and HLA-A*31:01 allele carriage ( P=.01522; odds ratio, 5.86; 95% CI, 1.46 to 23.4). Conclusions: Evaluated 28 HLA alleles were not associated with development of ILD. HLA-DQA1*05:05 allele was identified as a promising marker candidate that can predict patients with a higher risk of abemaciclib-induced hepatotoxicity. Further study is necessary to confirm the association in an independent population for managing liver safety risk during abemaciclib treatment. This result also implicates an immune-mediated mechanism for abemaciclib-related hepatotoxicity. Clinical trial information: UMIN000046611.

Correlation of patient HLA class I genotypes with severe immune-related adverse events: A retrospective study in Chinese population.

10586 Background: Immune checkpoint inhibitors (ICIs) are effective in multiple tumors. However, about 10% of immune-related adverse events (irAEs) are severe and can have serious or even life-threatening consequences for patients. We investigated whether Human leukocyte antigen (HLA) genes predispose to and thus hold a predictive role of developing of severe irAEs in Chinese population. Methods: In a case/control study, we collected data from patients with metastatic cancer treated with ICIs and developed severe irAEs (Grade ≥3 and required hospitalization). Patients treated with ICIs without any irAEs were used as controls. Data was collected from15th Nov, 2019 until 10th Oct, 2023. HLA typing was performed via next generation sequencing. Results: We enrolled 83 patients with severe irAEs and 286 patients treated with ICIs without any irAEs. We found HLA-B*15:27 (OR=9.1, X21,95 = 7.2, P = 0.008) and HLA-C*04:01 (OR=2.5, X21,95 = 7.0, P =0.008) were significantly associated with severe overall irAEs risk. When assessing irAE individually, a significant association between HLA-B*13:02 and serious myocarditis (OR = 3.4, X21,95 = 6.2, P =0.01) as well as striking enrichment for HLA-A*02:03 haplotypes in severe adrenal insufficiency (OR = 10.0, X21,95 = 19.1, P&lt;0.0001) were observed. Conclusions: Specific HLA alleles were associated with severe irAEs. Consideration of pre-prescription HLA typing and vigilance for serious reactions to ICIs are warranted.

The John Charnley Award: The Impact of Human Leukocyte Antigen Genotype on Bacterial Infection Rates and Successful Eradication in Total Hip Arthroplasty

BackgroundGenetics play an important role in several medical domains; however, the influence of human leukocyte antigen (HLA) genotype on the development of periprosthetic joint infection (PJI) in total hip arthroplasty (THA) remains unknown. The primary aim of this study was to determine if HLA genotype is associated with the development of bacterial PJI in THA. Secondarily, we evaluated the association between HLA genotype and PJI treatment success. MethodsA retrospective, matched, case-control study was performed using prospectively collected data from a single institution. A total of 49 patients who underwent primary THA were included, with a mean follow-up of 8.5 years (range, 4.2 to 12.9). The 23 cases (PJI) and 26 controls (no PJI) were matched for age, sex, follow-up, body mass index, primary diagnosis, and comorbidities (P > .05). High-resolution genetic analysis targeting 11 separate HLA loci was performed in all patients using serum samples. The HLA gene frequencies and carriage rates were determined and compared between cohorts. A subgroup analysis of PJI treatment success (18) and failure (5) was performed. Statistical significance was set at P = .10 for genetic analysis and at 0.05 for all other analyses. ResultsThere were 4 HLA alleles that were significantly associated with the development of PJI. The 3 at-risk alleles included HLA-C∗06:02 (odds ratio 5.25, 95% CI [confidence interval] 0.96 to 28.6, P = .064), HLA-DQA1∗04:01 (P = .096), and HLA-DQB1∗04:02 (P = .096). The single protective allele was HLA-C∗03:04 (odds ratio 0.12, 95% CI 0.01 to 1.10, P = .052). There were no specific HLA alleles that were associated with treatment success or failure. ConclusionsThis study suggests that there are at-risk and protective HLA alleles associated with the development of PJI in THA. To our knowledge, this is the first study to demonstrate an association between patient HLA genotype and the development of PJI. A larger study of the subject matter is necessary and warranted.

Genome-Wide Association Study Identifies IFIH1 and HLA-DQB1*05:02 Loci Associated With Anti-NMDAR Encephalitis.

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a rare autoimmune neurologic disorder, the genetic etiology of which remains poorly understood. Our study aims to investigate the genetic basis of this disease in the Chinese Han population. We performed a genome-wide association study and fine-mapping study within the major histocompatibility complex (MHC) region of 413 Chinese patients with anti-NMDAR encephalitis recruited from 6 large tertiary hospitals and 7,127 healthy controls. Our genome-wide association analysis identified a strong association at the IFIH1 locus on chromosome 2q24.2 (rs3747517, p = 1.06 × 10-8, OR = 1.55, 95% CI, 1.34-1.80), outside of the human leukocyte antigen (HLA) region. Furthermore, through a fine-mapping study of the MHC region, we discovered associations for 3 specific HLA class I and II alleles. Notably, HLA-DQB1*05:02 (p = 1.43 × 10-12; OR, 2.10; 95% CI 1.70-2.59) demonstrates the strongest association among classical HLA alleles, closely followed by HLA-A*11:01 (p = 4.36 × 10-7; OR, 1.52; 95% CI 1.29-1.79) and HLA-A*02:07 (p = 1.28 × 10-8; OR, 1.87; 95% CI 1.50-2.31). In addition, we uncovered 2 main HLA amino acid variation associated with anti-NMDAR encephalitis including HLA-DQβ1-126H (p = 1.43 × 10-12; OR, 2.10; 95% CI 1.70-2.59), exhibiting a predisposing effect, and HLA-B-97R (p = 3.40 × 10-8; OR, 0.63; 95% CI 0.53-0.74), conferring a protective effect. Computational docking analysis suggested a close relationship between the NR1 subunit of NMDAR and DQB1*05:02. Our findings indicate that genetic variation in IFIH1, involved in the type I interferon signaling pathway and innate immunity, along with variations in the HLA class I and class II genes, has substantial implications for the susceptibility to anti-NMDAR encephalitis in the Chinese Han population.

HLA variations in patients with diffuse large B-cell lymphoma and association with disease risk and prognosis: a case-control study.

Human leukocyte antigen (HLA) polymorphisms have been associated with the development of various autoimmune diseases, as well as malignant neoplasms. Non-Hodgkin lymphomas (NHLs) are a heterogenous group of lymphoid malignancies in which a genetic substrate has been established and is deemed to play a crucial role in disease pathogenesis. This study aimed to identify whether variations in the HLA gene region were associated with diffuse large B-cell lymphoma (DLBCL) risk and prognosis. We defined HLA class I (HLA-A, HLA-B, HLA-C) and class II (HLA-DRB1, HLA-DQB1) alleles in 60 patients with DLBCL and compared the results to those found by 236 healthy adult donors from the bone marrow bank of Northern Greece. HLA typing was performed by two molecular methods, Sequence - Specific Oligonucleotide HLA typing (SSO) and Sequence - Specific Primer HLA typing (SSP), from white blood cells recovered from peripheral blood. The phenotypic frequencies of HLA-A, HLA-B, HLA-C, HLA-DRB1 and HLA-DQB1 between patients and controls were compared with the 2-sided Fisher's exact test. Results with p-value <0.05 were considered statistically significant. Odds Ratios with 95% Confidence Intervals were calculated to further strengthen the results. The 2-sided Fisher's exact test was also applied to alleles found only in one of the two groups, while the odds ratios together with the confidence intervals were corrected with Haldane-Anscombe method. Among the studied HLA polymorphisms, the frequency HLA-C*12 allele was significantly lower in patients with DLBCL compared with control subjects (6.7% vs. 34.7%, OR = 0.16, 95% CI: 0.04-0.44). Frequency of HLA-B*39 was significantly lower in patients with DLBCL compared with controls, but due to the low frequency of this polymorphism in the studied population and small sample size, determinations regarding the significance of this findings were limited. Survival analysis revealed that the presence of HLA-C*12 was not associated with improved or worsened overall and progression-free survival. No statistically significant associations were observed in the phenotypic frequencies of HLA-A, HLA-DQB1, HLA-DRB1 and the rest of HLA-B alleles between the control and DLBCL groups. Collectively, our results provide valuable insight regarding the role of HLA variations on DLBCL risk. Further studies are required to consolidate our findings and ascertain the clinical implications of these genetic variations on DLBCL management and prognosis.

HLA-B*57:01-dependent intracellular stress in keratinocytes triggers dermal hypersensitivity reactions to abacavir.

Specific human leukocyte antigen (HLA) polymorphisms combined with certain drug administration strongly correlate with skin eruption. Abacavir hypersensitivity (AHS), which is strongly associated with HLA-B*57:01, is one of the most representative examples. Conventionally, HLA transmits immunological signals via interactions with T cell receptors on the cell surface. This study focused on HLA-mediated intracellular reactions in keratinocytes that might determine the onset of skin immunotoxicity by drug treatments. Abacavir exposure resulted in keratinocytes expressing HLA-B*57:01 exhibiting endoplasmic reticulum (ER) stress responses, such as immediate calcium release into the cytosol and enhanced HSP70 expression. In contrast, keratinocytes expressing HLA-B*57:03 (closely related to HLA-B*57:01) did not show these changes. This indicated that HLA-B*57:01 has a specific intracellular response to abacavir in keratinocytes in the absence of lymphocytes. Furthermore, abacavir exposure in HLA-B*57:01-expressing keratinocytes elevated the expression of cytokines/chemokines such as interferon-γ, interleukin-1β, and CCL27, and induced T lymphoblast migration. These effects were suppressed by ER stress relief using 4-phenylbutyrate (4-PB). HLA-B*57:01-transgenic mice also exhibited ER stress in epidermal areas following abacavir administration, and abacavir-induced skin toxicity was attenuated by the administration of 4-PB. Moreover, abacavir bound to HLA-B*57:01 within cells and its exposure led to HLA-B*57:01 protein aggregation and interaction with molecular chaperones in the ER of keratinocytes. Our results underscore the importance of HLA-mediated intracellular stress responses in understanding the onset of HLA-B*57:01-mediated AHS. We provide the possibility that the intracellular behavior of HLA is crucial for determining the onset of drug eruptions.

Integrating Reinforcement Learning and Monte Carlo Tree Search for enhanced neoantigen vaccine design.

Recent advances in cancer immunotherapy have highlighted the potential of neoantigen-based vaccines. However, the design of such vaccines is hindered by the possibility of weak binding affinity between the peptides and the patient's specific human leukocyte antigen (HLA) alleles, which may not elicit a robust adaptive immune response. Triggering cross-immunity by utilizing peptide mutations that have enhanced binding affinity to target HLA molecules, while preserving their homology with the original one, can be a promising avenue for neoantigen vaccine design. In this study, we introduced UltraMutate, a novel algorithm that combines Reinforcement Learning and Monte Carlo Tree Search, which identifies peptide mutations that not only exhibit enhanced binding affinities to target HLA molecules but also retains a high degree of homology with the original neoantigen. UltraMutate outperformed existing state-of-the-art methods in identifying affinity-enhancing mutations in an independent test set consisting of 3660 peptide-HLA pairs. UltraMutate further showed its applicability in the design of peptide vaccines for Human Papillomavirus and Human Cytomegalovirus, demonstrating its potential as a promising tool in the advancement of personalized immunotherapy.

Abstract 1201: Pervasive HLA disruption fuels cancer evolution

Abstract Disruption of the human leukocyte antigen (HLA) molecules has important implications for immune evasion and tumor evolution. However, although genomic loss of HLA is frequent in non-small cell lung cancer (NSCLC) and in some types of breast cancer, the extent and importance of transcriptomic disruption to HLA presentation, including transcript repression and alternative splicing (AS), remains unclear. To address this, we developed MHC Hammer, a tool to call HLA allele-specific mutations, loss of heterozygosity (LOH), transcriptional repression, and alternative splicing. We first assessed HLA allelic expression and the prevalence of AS in normal tissue. Applying MHC Hammer to 510 normal lung samples and 407 normal breast samples from the Genotype-Tissue Expression cohort, we identified extensive heterogeneity in HLA allelic expression depending on both the allele and tissue type. In addition, HLA allelic AS, occurring in at least 20% of the allele transcripts, was observed in 19% of normal lung and 13% of normal breast samples. Next, we applied MHC Hammer to 413 TRACERx NSCLCs and 743 TCGA breast tumours. While mutations were uncommon, HLA LOH was a frequent event, occurring in 32% of lung adenocarcinomas (LUAD) and 57% of lung squamous cell carcinomas (LUSC). We observed a similar rate of HLA LOH in estrogen receptor positive (ER+) and negative (ER-) tumors (ER+: 14%, ER-: 15%), while in triple negative breast tumours we observed a higher rate of LOH (31%). Due to the heterogeneity in HLA expression observed in the normal samples, to measure tumor specific HLA repression and alternative splicing, we restricted our analysis to tumours with WES, tumor and tumor-adjacent normal RNAseq data. This resulted in a cohort of 88 NSCLCs from the TRACERx study as well as 44 ER+ breast tumours from the TCGA cohort. 61% of LUAD, 75% of LUSC and 35% of ER+ tumours harbored class I HLA transcriptional repression that could not be explained by underlying genomic loss. 27% of LUAD, 7% of LUSC and 55% of ER+ breast tumor patients exhibited no HLA disruption. Tumor specific AS affecting HLA exons 2, 3 or 4, potentially disrupting HLA antigen presentation, was identified in 8% of LUADs, 11% of LUSC and 7% of ER+ breast tumours. Tumor specific AS of exon 5, yielding soluble HLA molecules without a transmembrane domain was identified in 20% of LUAD, 14% of LUSCs and 18% of ER+ breast tumours. LUAD and LUSC tumor regions without HLA LOH or repression were enriched for somatic HLA AS events and alleles with somatic HLA AS had a higher neoantigen burden than those without. We found no relationship between survival and HLA expression or AS in the normal tissue. However, consistent with the importance of HLA dysfunction in tumor evolution, LUADs with low HLA expression in at least one tumor region were associated with shorter disease-free survival, HLA LOH was more common in LUAD’s that metastasized and HLA repression was enriched in LUSC primary regions seeding metastases. Citation Format: Clare Puttick, Thomas P. Jones, Michelle Leung, Oriol Pich, Felipe Galvez Cancino, Jiali Liu, Manuel Varas-Godoy, Andrew Rowan, Carlos Martinez-Ruiz, Robert Bentham, Krijn K. Dijkstra, Rachel Rosenthal, Nnennaya Kanu, Kevin Litchfield, Roberto Salgado, David A. Moore, Peter Van Loo, Mariam Jamal-Hanjani, Sergio A. Quezada, Nicholas McGranahan, Charles Swanton. Pervasive HLA disruption fuels cancer evolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1201.

Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy Is Associated with HLA-A*3303 and HLA-DPB1*0501.

We determined the genetic association between specific human leucocyte antigen (HLA) loci and autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy. Our results showed that autoimmune GFAP astrocytopathy was associated with HLA-A*3303 (odds ratio [OR] = 2.02, 95% confidence interval [CI] = 1.32-3.06, p = 0.00072, padj. = 0.046) and HLA-DBP1*0501 (OR = 0.51, 95% CI = 0.36-0.71, p = 0.000048, padj. = 0.0062). Moreover, HLA-A*3303 carriers with the disease had a longer hospital stay (p = 0.0005) than non-carriers. This study for the first time provides evidence for a role of genetic factor in the development of autoimmune GFAP astrocytopathy. ANN NEUROL 2024;95:901-906.

Risk factors and survival analysis of human leukocyte antigen loss in relapsed acute myeloid leukaemia/myelodysplastic syndrome patients after allogeneic haematopoietic stem cell transplantation.

To investigate the clinical characteristics and risk factors of specific human leukocyte antigen loss (HLA loss) in relapsed acute myeloid leukaemia (AML)/myelodysplastic syndrome (MDS) patients after allogeneic haematopoietic stem cell transplantation (allo-HSCT), and compare the responses of patients with HLA loss relapse with those without HLA loss (non-HLA loss) to different treatment regimens. Clinical data of traceable patients with AML/MDS after myeloablative allo-HSCT in our centre between January 2010 and June 2021, who experienced disease relapse after the transplantation, were collected. The patients were divided into the HLA loss relapse group and the non-HLA loss relapsed group based on HLA loss gene test findings by next-generation sequencing. The patients' median overall survival (OS) after the relapse were compared, and univariate and multivariate analyses were performed using the Kaplan-Meier survival curve and Cox proportional hazard model to explore the responses to different treatments after relapse. A total of 2359 patients were selected. Retrospective HLA gene loss gene detection was performed for the deoxyribonucleic acid in 179 relapsed patients, including 47 patients in the HLA loss group (27.2%), 126 patients in the non-HLA loss group (72.8%) and 6 patients were excluded due to a lack of confirmed results. There was no significant statistical difference in the baseline characteristics of patients between the two groups, but as to transplantation-related characteristics, the donor-recipient relationship and HLA mismatched loci were statistically different between the two groups (both p < 0.001). Multivariate Cox analysis showed that more HLA mismatched loci ≥3 (HR = 3.66; 95% CI: 1.61-8.31; p = 0.002), time (≤6 months) from HSCT to relapse (HR = 7.92; 95% CI: 3.35-18.74; p < 0.001) and donor chimerism (CD3) in bone marrow at relapse (HR = 1.02; 95% CI: 1.00-1.03; p = 0.036) were independent factors affecting HLA loss relapse. The ratio of negative conversion of FLT3-ITD or CEBPA mutation was significantly lower in patients with post-transplantation HLA loss relapse than in the non-HLA loss group (0.0% vs. 45.5%, p = 0.003; 0.0% vs. 80.0%, p = 0.035), with none of the patients with FLT3-ITD or CEBPA mutation turned negative in the HLA loss group. The number of gene mutations turned negative when relapse in the non-HLA loss group was remarkably higher than that in the HLA loss group (p = 0.001). Using donor lymphocyte infusion (DLI) could not prolong OS for the HLA loss group (p = 0.42). Nevertheless, second transplantation had a significant positive impact on OS in the HLA loss group (p = 0.017), although only five patients in the HLA loss group underwent second transplantation. However, patients in the non-HLA loss group using DLI had a relatively longer OS time than those without DLI (p = 0.017). Second transplantation could also prolong OS in the non-HLA loss group, but the effect was not as significant as in the HLA loss group (p = 0.053). In summary, HLA loss detection is essential for patients with recurrence after transplantation, especially for those with more HLA mismatched loci and non-sibling donor. Furthermore, the detection of HLA loss has a guiding role in choosing subsequent therapy when relapsed, as secondary transplantation is more suitable than DLI for those with HLA loss.

Non-Host Factors Influencing Onset and Severity of Celiac Disease

Celiac Disease (CeD) is a chronic autoimmune condition driven by gluten ingestion in genetically predisposed individuals, resulting in inflammatory lesions in the proximal small intestine. While the presence of specific human leukocyte antigen (HLA) linked haplotypes and gluten consumption are necessary for disease development, they alone do not account for the variable onset of CeD in susceptible individuals. This review explores the multifaceted role of non-host factors in CeD development, including dietary and microbial influences. We discuss clinical associations and observations highlighting the impact of these factors on disease onset and severity. Furthermore, we discuss studies in CeD-relevant animal models that offer mechanistic insights into how diet, the microbiome, and enteric infections modulate CeD pathogenesis. Finally, we address the clinical implications and therapeutic potential of understanding these cofactors, offering a promising avenue for preventive and therapeutic interventions in CeD management.

Kikuchi disease in acute leukaemia: a distinct clinical syndrome with HLA association.

To report the clinicopathological features of Kikuchi disease in patients with acute leukaemia, emphasising similarities among cases. In a cohort of 454 Kikuchi disease patients, we identified three cases of concurrent acute leukaemia. These patients shared similar clinical traits, with Kikuchi disease emerging approximately a month after induction chemotherapy onset, featuring neck-region lymphadenopathy. Notably, two patients were middle-aged, deviating from the typical age distribution of Kikuchi disease. Histologically, these cases aligned with typical Kikuchi disease. Negative immunohistochemical stains (CD34, CD117, ERG, TdT) indicated the absence of extramedullary leukaemic infiltration. Herpes simplex virus immunohistochemical staining was also negative. Significantly, a human leucocyte antigen (HLA) association was observed in these three cases. HLA-B*15:01, C*04:01, and DRB1*04:06 were more prevalent in these patients compared to the general population (compared with three independent control cohorts: Taiwanese Han Chinese (n = 504), Tzu Chi Taiwanese bone marrow donors (n = 364) and Hong Kong Chinese (n = 5266)). Our study underscores the unique link between Kikuchi disease and acute leukaemia, characterised by specific features and HLA associations. This underlines Kikuchi disease as a possible differential diagnosis in pertinent clinical scenarios. Furthermore, this syndrome offers insights into postchemotherapy immunology in acute leukaemia, enhancing comprehension.

Elucidating the Mechanisms Underlying Interindividual Differences in the Onset of Adverse Drug Reactions.

Idiosyncratic drug toxicities (IDTs) pose a significant challenge; they are marked by life-threatening adverse reactions that emerge aftermarket release and are influenced by intricate genetic and environmental variations. Recent genome-wide association studies have highlighted a strong correlation between specific human leukocyte antigen (HLA) polymorphisms and IDT onset. This review provides an overview of current research on HLA-mediated drug toxicities. In the last six years, HLA-transgenic (Tg) mice have been instrumental in advancing our understanding of these underlying mechanisms, uncovering systemic immune reactions that replicate human drug-induced immune stimulation. Additionally, the potential role of immune tolerance in shaping individual differences in adverse effects highlights its relevance to the interplay between HLA polymorphisms and IDTs. Although HLA-Tg mice offer valuable insights into systemic immune reactions, further exploration is essential to decipher the intricate interactions that lead to organ-specific adverse effects, especially in organs such as the skin or liver. Navigating the intricate interplay of HLA, which may potentially trigger intracellular immune responses, this review emphasizes the need for a holistic approach that integrates findings from both animal models and molecular/cellular investigations. The overarching goal is to enhance our comprehensive understanding of HLA-mediated IDTs and identify factors shaping individual variations in drug reactions. This review aims to facilitate the development of strategies to prevent severe adverse effects, address existing knowledge gaps, and provide guidance for future research initiatives in the field of HLA-mediated IDTs.

Killer cell immunoglobulin-like receptors in Thai patients with multiple myeloma.

Natural killer (NK) cells have been implicated in the immune response against multiple myeloma (MM) cells. Killer cell immunoglobulin-like receptors (KIRs) regulate NK cell activity by recognizing specific human leukocyte antigen (HLA) class I as ligands. To investigate the association of KIR genes and ligands with MM in the Thai population. KIR gene polymorphisms and their HLA ligands were investigated in 66 Thai patients with MM and 200 healthy controls. The frequencies of KIR3DL1 and 2DS4 were significantly lower in myeloma patients than in controls (P = 0.02). The frequencies of KIR3DL1, 2DS4, 2DL1 with C2, and 3DL1 with Bw4 were significantly higher in the patients achieving > very good partial response (VGPR) than those achieving ≤ VGPR after treatment with bortezomib (P = 0.009, 0.009, 0.01, and 0.02, respectively). This study suggests the association of KIR genes with the protection against MM and the association of inhibitory KIR and ligands with the response to treatment in MM.