Histocompatibility Research Articles

THE RELEVANCE OF HLA-II HISTOCOMPATIBILITY ANTIGENS IN PREDICTING THE RISK OF DEVELOPING A NUMBER OF BULLOUSE DERMATOSES

Background. Bullous dermatoses are a group of severe heterogeneous diseases that are potentially life threatening and significantly worsen its quality. Aims. To establish the regularities of the implementation of individual links in the immunopathogenesis of bullous dermatoses (BD) using the example of pemphigus vulgaris, bullous pemphigoid and benign familial pemphigus in accordance with the data of clinical and immunogenetic studies to develop scientifically based approaches to predicting the course and personification of therapy for bullous dermatoses. Methods. A prospective open, simple, comparative, scientific study included 101 patients (men – 33, women – 68) with bullous dermatoses. The study was conducted from 2017 to 2023. Results. Statistically significant differences were revealed for a number of HLA-II indicators. Carriers of HLA-DRB1*3, DRB1*4, DRB1*14, DRB1*16, DQB1*0304, DQB1*0502-4, DQB1*0503, DQB1*02 and DQA1*0301 should be identified as a risk group for the development of PV, BFP, BP. Patients carrying histocompatibility antigens HLA-DRB1*15, DRB1*17, DQB1*201, DQB1*303, DQB1*602-8 have increased resistance to the above-mentioned bullous dermatoses. Conclusions. An association was found between histocompatibility antigens HLA-II, pemphigus vulgaris, bullous pemphigoid and benign familial pemphigus. The data obtained can be used to predict the development of the above-mentioned diseases, develop a set of preventive recommendations, verify the correct diagnosis in the early stages of diseases and minimize the risks of exposure to exposom factors.

Evaluation of the Frequency of HLA-DQ2/DQ8 Genes Among Patients with Celiac Disease and Those on a Gluten-Free Diet.

Celiac disease (CD) is a chronic, permanent, gluten-dependent disease that manifests itself with inflammation of the small intestine and malabsorption in genetically predisposed individuals with HLA-DQ2 and -DQ8 (human leukocyte antigen) histocompatibility antigens. The diagnostic criteria for celiac disease have undergone numerous modifications over the years. The aim of the study is to evaluate the frequency of HLA-DQ2/DQ8 genes in a group of patients with celiac disease diagnosed in 1980-2010 in order to verify the primary diagnosis of CD. The study group included 50 patients, 13 men and 37 women, who had been diagnosed with celiac disease many years ago based on histopathological criteria and improvement of health condition after receiving a gluten-free diet. The control group consisted of 31 healthy volunteers, 18 women and 13 men. All subjects underwent a genetic analysis assessing the presence of histocompatibility antigens HLA-DQ2.2, -DQ2.5, and -DQ8, along with the assessment of alleles encoding the α and β subunits of the antigens, according to European Society of Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines from 2020, using the EUROarray technique at EUROIMMUNE®. In the study group, 12 (24%) patients did not meet the genetic criteria. Among the remaining patients (Group 1) with celiac disease, the presence of HLA-DQ2.5 (50.0% vs. 9.68%; p < 0.01) and the co-occurrence of both alleles of HLA-DQ2 (31.6% vs. 6.45%; p < 0.05) were detected significantly more frequently than in the control group. Among patients with celiac disease, the prevalence of HLA-DQ8 was also slightly more frequent (13.2% vs. 3.23%; p > 0.05). Patients who did not meet the genetic criteria for celiac disease (Group 2) had a single string α-HLA-DQ2.5 significantly more often than control subjects (66.67% vs. 38.71%; p < 0.05). Among patients with celiac disease diagnosed before 2010, based on the 2020 ESPGHAN criteria, it is advisable to verify the previous diagnosis, taking into account genetic criteria.

Comparative retrospective analysis of cord blood transplantation with ATG-containing conditioning regimens and haploidentical stem cell transplantation: similar survival outcomes with reduced incidence of GVHD

Background Cord blood (CB) is widely used in treating haematologic disorders due to its broad availability, tolerance to significant histocompatibility antigen disparities, and low incidence of chronic graft-versus-host disease (cGVHD). The cord blood transplantation (CBT) with anti-thymocyte globulin (ATG)-containing conditioning regimens shows promise in this regard. Methods We conducted a retrospective review of data from patients who underwent CBT at our centre from August 2003 to December 2022. Patients undergoing CBT with ATG were matched with those who received HLA-haploidentical haematopoietic stem cell transplantation (haplo-HSCT). Propensity score matching (PSM) was utilized to form 105 matched pairs (140 patients) for comprehensive trial analysis. Results The cumulative incidence of neutrophil and platelet engraftment was significantly lower in the CBT group. Patients in the CBT group exhibited significantly lower incidences of grade II-IV acute GVHD (aGVHD) and cGVHD compared to the haplo-HSCT group (8.57% vs. 29.52%, p = 0.012; 20% vs. 39.05%, p = 0.031). The overall survival (OS) rate for the CBT and haplo-HSCT groups showed no significant difference. In patients with leukaemia, the CBT cohort showed better OS, GVHD-free and relapse-free survival (GRFS), as well as a lower incidence of disease relapse, although there was no statistical difference. Conclusion Our single-centre retrospective long-term follow-up investigations indicated that although the implantation rate of CBT is lower than that of haplo-HSCT, patients undergoing CBT with ATG-containing conditioning regimens may have a comparable overall survival with a lower risk of GVHD compared to those undergoing haplo-HSCT.

DNA barcoded peptide-MHC multimers to measure and monitor minor histocompatibility antigen-specific T cells after allogeneic stem cell transplantation

Allogeneic stem cell transplantation (alloSCT) provides a curative treatment option for hematological malignancies. After HLA-matched alloSCT, donor-derived T cells recognize minor histocompatibility antigens (MiHAs), which are polymorphic peptides presented by...

Allorecognition Unveiled: Integrating Recent Breakthroughs Into the Current Paradigm.

In transplantation, genetic differences between donor and recipient trigger immune responses that cause graft rejection. Allorecognition, the process by which the immune system discriminates allogeneic grafts, targets major histocompatibility complex (MHC) and minor histocompatibility antigens. Historically, it was believed that allorecognition was solely mediated by the recipient's adaptive immune system recognizing donor-specific alloantigens. However, recent research has shown significant roles for innate immune components, such as lymphoid and myeloid cells, which are sometimes triggered by the mere absence of a self-protein in the graft. This review integrates recent breakthroughs into the current allorecognition paradigm based on the well-established direct and indirect pathways, emphasizing the semi-direct pathway where recipient antigen-presenting cells (APCs) acquire donor MHC molecules, and the inverted direct pathway where donor CD4+ T cells within the graft activate recipient B cells to produce donor-specific antibodies (DSAs). The review also explores the role of natural killer (NK) cells in both promoting and inhibiting graft rejection, highlighting their dual role in innate allorecognition. Additionally, it discusses the emerging understanding of myeloid cell-mediated allorecognition and its implications for initiating adaptive immune responses. These insights aim to provide a more comprehensive understanding of allorecognition, potentially leading to improved transplant outcomes.

RNA-seq Based Transcriptome Analysis Reveals Role of Myoglobin in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which manifests as joint destruction and bone erosion, could be caused by both genetic and environmental factors. Currently, the causes of RA are unknown, and targeted therapies are often associated with side effects and contraindications. The detection rate of RA in women is higher than men (3:1), however, there is still a lack of comprehensive understanding of the relationship between sex and RA. We hypothesized gender differences in RA prevalence and their associated mechanisms by performing genome-wide transcriptome analysis of synovial biopsy samples. The results indicated that myoglobin (MB) was differentially expressed between males and females, with higher expression in males than females in healthy populations, while the opposite was observed in RA patients. MB interacted with HLA class II histocompatibility antigen, DM beta (HLA-DMB) and the inflammatory factor interleukin 6 (IL-6) in the human synovial cell line MH7A.

Improving long-term kidney allograft survival by rethinking HLA compatibility: from molecular matching to non-HLA genes.

Optimizing immunologic compatibility in organ transplantation extends beyond the conventional approach of Human Leukocyte Antigen (HLA) antigen matching, which exhibits significant limitations. A broader comprehension of the roles of classical and non-classical HLA genes in transplantation is imperative for enhancing long-term graft survival. High-resolution molecular HLA genotyping, despite its inherent challenges, has emerged as the cornerstone for precise patient-donor compatibility assessment. Leveraging understanding of eplet biology and indirect immune activation, eplet mismatch calculators and the PIRCHE-II algorithm surpass traditional methods in predicting allograft rejection. Understanding minor histocompatibility antigens may also present an opportunity to personalize the compatibility process. While the application of molecular matching in deceased donor organ allocation presents multiple technical, logistical, and conceptual barriers, rendering it premature for mainstream use, several other areas of donor-recipient matching and post-transplant management are ready to incorporate molecular matching. Provision of molecular mismatch scores to physicians during potential organ offer evaluations could potentially amplify long-term outcomes. The implementation of molecular matching in living organ donation and kidney paired exchange programs is similarly viable. This article will explore the current understanding of immunologic matching in transplantation and the potential applications of epitope and non-epitope molecular biology and genetics in clinical transplantation.

Female-to-male allogeneic transplantation affects outcomes differently according to the type of haplo-transplantation

Allogeneic hematopoietic stem cell transplantation from a female donor to a male recipient (female-to-male allo-HCT) is a well-established risk factor for chronic graft-versus-host disease (GVHD) and non-relapse mortality (NRM). The inferior outcomes of female-to-male allo-HCT are considered to be due to allo-immunity against H-Y antigens. However, the influence of minor histocompatibility antigens in haplo-identical allo-HCT remains to be elucidated. We investigated the impact of female-to-male allo-HCT according to the haplo-HCT subtype. In the post-transplant cyclophosphamide (PTCY) cohort (n = 660), a female-to-male sex-mismatch was significantly associated with a decreased risk of relapse (HR: 0.70 [95% CI: 0.49-0.99], P = 0.045), but not with overall survival (OS) or NRM (HR: OS 0.89 [95% CI: 0.68-1.16], P = 0.40; NRM 0.98 [95% CI: 0.68-1.41], P = 0.90). On the other hand, in the non-PTCY cohort (n = 219), a female-to-male sex-mismatch was associated with inferior risks of OS and NRM, but was not associated with relapse. These results suggested that the survival impact of the haplo-HCT subtype differed according to the presence of a sex-mismatch. PTCY might be feasible for overcoming the inferiority of female-to-male allo-HCT and might preserve a GVL effect against H-Y antigens.

Development of Bone Marrow Transplantation Strategies

The use of alternative stem cell sources, the growth of supportive healthcare facilities, and the expansion of indications for bone marrow transplantation (BMT) as well as partially matched donors from the same family are all continuing evolutionary trends as the use of BMT has been developed and expanded to include donors who are not related by blood but have Partial histocompatibility antigen compatibility. Although the outcomes of these transplants are not as good as those performed with first-degree siblings, patients with leukemia, aplastic anemia, and immunodeficiency disorders who cannot receive treatment otherwise they can receive it now. Patients suffering from diseases such as acute myeloid leukemia, acute lymphoblastic leukemia, and Hodgkin lymphoma also show success with autologous bone marrow transplants. Furthermore, bone marrow or blood stem cell support is used after intensive chemotherapy. Patients with stage II, III, and IV breast cancer can benefit from treatment with bone marrow cells found in peripheral blood. In this review, the most important developments in autologous and allogeneic bone marrow transplantation, the control of infectious diseases, and the use of gene therapy to alter genetic disorders that are transmitted from parents to their offspring through bone marrow or peripheral blood infusions are outlined.

Frequency of HLA-B27 Haplotype Among Patients with Acute Anterior Uveitis and Controls in Ethiopia

ABSTRACT Purpose We compared the distribution of the HLA-B27 allele among Ethiopian patients with acute anterior uveitis (AAU) and controls without that disease. Methods The clinical features of patients were collected from their medical records. HLA-B27 genotyping was performed for 64 patients, with AAU using the real-time polymerase chain reaction (RT-PCR), and the results were compared to those from a panel of 192 healthy, unrelated volunteer control participants (refraction patients and volunteers) free of signs of anterior uveitis. Other outcomes were assessed comparing HLA-B27 positive vs. negative patients. Results The histocompatibility antigen HLA-B27 was identified in 6 out of 64 (9.4%) AAU patients, compared with 1.0% in controls (Odds Ratio = 9.8, 95% CI (1.93, 50.01)). Sub-group analysis of the cases revealed that patients with HLA-B27 positivity had a higher incidence of ocular hypertension (Odds Ratio = 5.93, 95% CI (1.29, 27.2)). Conclusion The antigen HLA-B27 was represented ~10-fold more frequently in the patient group than in the control group. HLA-B27 allele distribution in both cases and controls is lower than in reports from Caucasian and Asian populations, but similar to South Africa.

Systematic identification of minor histocompatibility antigens predicts outcomes of allogeneic hematopoietic cell transplantation.

T cell alloreactivity against minor histocompatibility antigens (mHAgs)-polymorphic peptides resulting from donor-recipient (D-R) disparity at sites of genetic polymorphisms-is at the core of the therapeutic effect of allogeneic hematopoietic cell transplantation (allo-HCT). Despite the crucial role of mHAgs in graft-versus-leukemia (GvL) and graft-versus-host disease (GvHD) reactions, it remains challenging to consistently link patient-specific mHAg repertoires to clinical outcomes. Here we devise an analytic framework to systematically identify mHAgs, including their detection on HLA class I ligandomes and functional verification of their immunogenicity. The method relies on the integration of polymorphism detection by whole-exome sequencing of germline DNA from D-R pairs with organ-specific transcriptional- and proteome-level expression. Application of this pipeline to 220 HLA-matched allo-HCT D-R pairs demonstrated that total and organ-specific mHAg load could independently predict the occurrence of acute GvHD and chronic pulmonary GvHD, respectively, and defined promising GvL targets, confirmed in a validation cohort of 58 D-R pairs, for the prevention or treatment of post-transplant disease recurrence.

Bioinformatic elucidation of conserved epitopes to design a potential vaccine candidate against existing and emerging SARS-CoV-2 variants of concern

Bioinformatic elucidation of conserved epitopes to design a potential vaccine candidate against existing and emerging SARS-CoV-2 variants of concern

Knockdown of swine leukocyte antigen expression in porcine lung transplants enables graft survival without immunosuppression.

Immune rejection remains the major obstacle to long-term survival of allogeneic lung transplants. The expression of major histocompatibility complex molecules and minor histocompatibility antigens triggers allogeneic immune responses that can lead to allograft rejection. Transplant outcomes therefore depend on long-term immunosuppression, which is associated with severe side effects. To address this problem, we investigated the effect of genetically engineered transplants with permanently down-regulated swine leukocyte antigen (SLA) expression to prevent rejection in a porcine allogeneic lung transplantation (LTx) model. Minipig donor lungs with unmodified SLA expression (control group, n = 7) or with modified SLA expression (treatment group, n = 7) were used to evaluate the effects of SLA knockdown on allograft survival and on the nature and strength of immune responses after terminating an initial 4-week period of immunosuppression after LTx. Genetic engineering to down-regulate SLA expression was achieved during ex vivo lung perfusion by lentiviral transduction of short hairpin RNAs targeting mRNAs encoding β2-microglobulin and class II transactivator. Whereas all grafts in the control group were rejected within 3 months, five of seven animals in the treatment group maintained graft survival without immunosuppression during the 2-year monitoring period. Compared with controls, SLA-silenced lung recipients had lower donor-specific antibodies and proinflammatory cytokine concentrations in the serum. Together, these data demonstrate a survival benefit of SLA-down-regulated lung transplants in the absence of immunosuppression.

TransfIGN: A Structure-Based Deep Learning Method for Modeling the Interaction between HLA-A*02:01 and Antigen Peptides.

The intricate interaction between major histocompatibility complexes (MHCs) and antigen peptides with diverse amino acid sequences plays a pivotal role in immune responses and T cell activity. In recent years, deep learning (DL)-based models have emerged as promising tools for accelerating antigen peptide screening. However, most of these models solely rely on one-dimensional amino acid sequences, overlooking crucial information required for the three-dimensional (3-D) space binding process. In this study, we propose TransfIGN, a structure-based DL model that is inspired by our previously developed framework, Interaction Graph Network (IGN), and incorporates sequence information from transformers to predict the interactions between HLA-A*02:01 and antigen peptides. Our model, trained on a comprehensive data set containing 61,816 sequences with 9051 binding affinity labels and 56,848 eluted ligand labels, achieves an area under the curve (AUC) of 0.893 on the binary data set, better than state-of-the-art sequence-based models trained on larger data sets such as NetMHCpan4.1, ANN, and TransPHLA. Furthermore, when evaluated on the IEDB weekly benchmark data sets, our predictions (AUC = 0.816) are better than those of the recommended methods like the IEDB consensus (AUC = 0.795). Notably, the interaction weight matrices generated by our method highlight the strong interactions at specific positions within peptides, emphasizing the model's ability to provide physical interpretability. This capability to unveil binding mechanisms through intricate structural features holds promise for new immunotherapeutic avenues.

Microbiota dictate T cell clonal selection to augment graft-versus-host disease after stem cell transplantation

Allogeneic Tcell expansion is the primary determinant of graft-versus-host disease (GVHD), and current dogma dictates that this is driven by histocompatibility antigen disparities between donor and recipient. This paradigm represents a closed genetic system within which donor Tcells interact with peptide-major histocompatibility complexes (MHCs), though clonal interrogation remains challenging due to the sparseness of the Tcell repertoire. We developed a Bayesian model using donor and recipient Tcell receptor (TCR) frequencies in murine stem cell transplant systems to define limited common expansion of Tcell clones across genetically identical donor-recipient pairs. A subset of donor CD4+ Tcell clonotypes differentially expanded in identical recipients and were microbiota dependent. Microbiota-specific Tcells augmented GVHD lethality and could target microbial antigens presented by gastrointestinal epithelium during an alloreactive response. The microbiota serves as a source of cognate antigens that contribute to clonotypic Tcell expansion and the induction of GVHD independent of donor-recipient genetics.

Mayer–Rokitansky–Küster–Hauser syndrome managed with McIndoe’s vaginoplasty: a case series and literature review

Introduction: Mayer–Rokitansky–Küster–Hauser (MRKH) syndrome is a congenital anomaly characterized by the absence of the uterus and the upper two-thirds of the vagina. It is a rare congenital anomaly with an incidence of 1 in 5000 female live births. Case series: The authors describe three cases of females presenting with primary amenorrhoea who were diagnosed with MRKH syndrome. The patients were managed with McIndoe’s vaginoplasty with neovagina creation with an amnion graft. Discussion: Management of MRKH syndrome involves vaginoplasty with neovagina creation. The approach to neovagina creation can be done surgically or non-surgically. Non-surgical creation of the vaginal cavity involves serial use of vaginal dilators, while there are several ways for surgical creation of neovagina. The modified Abbe-McIndoe procedure using amnion to create neovagina is a minimally invasive, rapid, and simple procedure with no risk of immune rejection because the amnion membrane lacks histocompatibility antigens. In addition, the graft is also readily available, storable, and inexpensive. Conclusion: Diagnosis of MRKH syndrome can be made when a young female with primary amenorrhoea and normal secondary sexual characteristics has agenesis of the uterus, and upper two-thirds of the vagina revealed on ultrasonography or magnetic resonance imaging. The patient can be offered treatment with vaginoplasty with neovagina creation.

A phase 1 trial of TSC-100 and TSC-101, engineered T cell therapies that target minor histocompatibility antigens to eliminate residual disease after hematopoietic cell transplantation.

TPS2678 Background: Engineered T cell therapies such as CAR-T cell therapies have transformed the treatment of B-cell but not non-B cell hematologic malignancies. Allogeneic hematopoietic cell transplantation (HCT) remains the best curative option for hematologic malignancies but ~40% of patients relapse post-HCT with up to 90% mortality due to residual disease post-HCT. A potential solution is targeting minor histocompatibility antigens (MiHAs) that are homogenously expressed on all hematopoietic cells and are genetically mismatched between donors and patients undergoing HCT. These mismatches enable engineered T cells to selectively eliminate residual patient hematopoietic cells, normal or malignant, leaving donor cells untouched. TScan has developed allogeneic donor derived T-cell products TSC-100 and TSC-101, targeting MiHAs HA-1 and HA-2 respectively, both presented on HLA-A*02:01. By choosing HCT patients who are HLA-A*02:01 positive (&gt;98% of whom are either HA-1 or HA-2 positive) and donors who are either HLA-A*02:01 or MiHA negative, TSC-100 or TSC-101 can potentially eliminate all residual patient-derived hematopoietic cells after HCT, to prevent disease relapse. Methods: Study NCT05473910 is a multi-center, multi-arm, non-randomized controlled Phase 1 umbrella study evaluating the feasibility, safety and preliminary efficacy of TSC-100 and TSC-101. Inclusion criteria include adults with AML, MDS or ALL eligible for reduced intensity conditioning-based haploidentical donor transplantation from HLA or MiHA mismatched donors. HLA-A*02:01-positive patients undergo HA-1/ HA-2 testing and are assigned to either TSC-100 or TSC-101 treatment arms in addition to HCT. HLA-A*02:01-negative patients in the control arm receive HCT alone. Upon count recovery after HCT, patients in treatment arms receive either TSC-100 or TSC-101, administered as single or two doses. Primary endpoints include adverse event profiles and dose limiting toxicities. Secondary endpoints include relapse rates, disease-free survival and overall survival. Exploratory endpoints include surrogates of efficacy such as donor chimerism rates and kinetics and minimal residual disease (MRD) rates. Donor chimerism is measured by standard STR-based and novel high-sensitivity NGS-based assays to quantify residual patient-derived hematopoietic cells. MRD is measured before and after HCT using flow cytometry and NGS. Together, these assays measure elimination of residual patient hematopoietic cells, malignant or normal, and could provide early evidence of biological activity. Clinical trial information: NCT05473910 .

Hypoxia- and Postirradiation reoxygenation-induced HMHA1/ARHGAP45 expression contributes to cancer cell invasion in a HIF-dependent manner

BackgroundCancer cells in severely hypoxic regions have been reported to invade towards tumour blood vessels after surviving radiotherapy in a postirradiation reoxygenation- and hypoxia-inducible factor (HIF)-dependent manner and cause recurrence. However, how HIF induces invasiveness of irradiated and reoxygenated cancer cells remains unclear.MethodsHere, we identified human minor histocompatibility antigen 1 (HMHA1), which has been suggested to function in cytoskeleton dynamics and cellular motility, as a responsible factor and elucidated its mechanism of action using molecular and cellular biology techniques.ResultsHMHA1 expression was found to be induced at the transcription initiation level in a HIF-dependent manner under hypoxia. Boyden chamber invasion assay revealed that the induction of HMHA1 expression is required for the increase in invasion of hypoxic cancer cells. Reoxygenation treatment after ionising radiation in vitro that mimics dynamic changes of a microenvironment in hypoxic regions of tumour tissues after radiation therapy further enhanced HMHA1 expression and invasive potential of HMHA1 wildtype cancer cells in ROS- and HIF-dependent manners, but not of HMHA1 knockout cells.ConclusionThese results together provide insights into a potential molecular mechanism of the acquisition of invasiveness by hypoxic cancer cells after radiotherapy via the activation of the ROS/HIF/HMHA1 axis.

HA-1–targeted T-cell receptor T-cell therapy for recurrent leukemia after hematopoietic stem cell transplantation

Relapse is the leading cause of death after allogeneic hematopoietic stem cell transplantation (HCT) for leukemia. T cells engineered by gene transfer to express T cell receptors (TCR; TCR-T) specific for hematopoietic-restricted minor histocompatibility (H) antigens may provide a potent selective antileukemic effect post-HCT. We conducted a phase 1 clinical trial using a novel TCR-T product targeting the minor H antigen, HA-1, to treat or consolidate treatment of persistent or recurrent leukemia and myeloid neoplasms. The primary objective was to evaluate the feasibility and safety of administration of HA-1 TCR-T after HCT. CD8+ and CD4+ T cells expressing the HA-1 TCR and a CD8 coreceptor were successfully manufactured from HA-1-disparate HCT donors. One or more infusions of HA-1 TCR-T following lymphodepleting chemotherapy were administered to 9 HCT recipients who had developed disease recurrence after HCT. TCR-T cells expanded and persisted invivo after adoptive transfer. No dose-limiting toxicities occurred. Although the study was not designed to assess efficacy, 4 patients achieved or maintained complete remissions following lymphodepletion and HA-1 TCR-T, with 1 patient still in remission at >2 years. Single-cell RNA sequencing of relapsing/progressive leukemia after TCR-T therapy identified upregulated molecules associated with T-cell dysfunction or cancer cell survival. HA-1 TCR-T therapy appears feasible and safe and shows preliminary signals of efficacy. This clinical trial was registered at ClinicalTrials.gov as #NCT03326921.

Impact of Circulating Lymphoma Cells on HLA Typing Outcomes in Patients with Diffuse Large B-Cell Lymphoma: A Case Report

Recipient's high resolution HLA typing is required in allogeneic hematopoietic cell transplantation from unrelated donors, as well as for haploidentical family donors. For these purposes, Next-Generation Sequencing (NGS) methods are the gold standard. We present a case of a patient with an incorrect HLA typing result caused by the population of circulating lymphoma cells. The first HLA examination was performed from peripheral blood (PB) using NGS in the active phase of diffuse large B-cell lymphoma with bone marrow involvement. Because of rare and inconclusive results, confirmed twice for the A* locus (A*02:32N), real-time polymerase chain reaction (RT-PCR)was performed. With RT-PCR method, we obtained more expected results according to the population allele frequency: in HLA-A locus (A*02:01) but also in DQB1 (DQB1*03:01, not as in NGS - DQB1*03:10). For the final verification, we used swab material and we obtained unambiguous NGS result with expected, frequent HLA-A*02:01 and DQB1*03:01 alleles corresponding to the RT-PCR result from PB. To conclude, we suspect that the discrepancies between NGS and RT-PCR results were caused by the presence of a significant amount of circulating lymphoma cells in the peripheral blood sample. Lymphomagenic mutations may involve the histocompatibility antigen coding region and affect HLA expressed on malignant cells. This finding may be relevant for the selection of test material in primary and confirmatory HLA testing in patients with active hematological malignancies because of the strong impact of incorrect HLA typing on the procedure of a donor selection.