HLA Testing Research Articles

A National Programme of a High Throughput Axiom Array Genotyping Platform for HEA and HLA Testing for All Patients with Sickle Cell, Thalassaemia and Transfusion Dependent Rare Inherited Anaemias in the United Kingdom

A National Programme of a High Throughput Axiom Array Genotyping Platform for HEA and HLA Testing for All Patients with Sickle Cell, Thalassaemia and Transfusion Dependent Rare Inherited Anaemias in the United Kingdom

Harmonisation of the HLA tests for the diagnosis of coeliac disease: experiences from the Czech external proficiency testing program.

Coeliac disease (CD) is an autoimmune disorder caused by the ingestion of gluten-containing grains. One of the prerequisites for the development of the disease is the presence of specific combinations of HLA alleles at the DQA1 and DQB1 loci. The HLA test is a supportive diagnostic test. In the Czech Republic, approximately 3,500 HLA tests for CD diagnosis are performed annually in almost three dozen laboratories. The HLA Department of the Institute of Haematology and Blood Transfusion in Prague has been offering the EPT "Detection of HLA Alleles Associated with Diseases" for more than 10years. The results are evaluated in terms of the correct determination of predisposing alleles/allelic groups and clinical interpretation. Every year, we notice some problems with the detection of CD-associated alleles and the interpretation of results. Annual workshops are part of this EPT, and they also include recommendations for the interpretation of results. This interpretation is evolving based on the current knowledge in the field. The current recommendation for interpretation was adopted in 2023, dividing HLA-DQA1/DQB1 genotypes into three categories: 1) detected HLA genotype is associated with predisposition to coeliac disease; 2) coeliac disease could not be excluded based on the detected HLA genotype; 3) coeliac disease could be excluded with high probability based on the detected HLA genotype. The quality of examination is increasing but still needs improvement. Correct results and accurate interpretation can inform clinicians' decisions about the diagnosis of coeliac disease in appropriate patients.

Sensitive HLA antibody testing and the risk of antibody-mediated rejection and graft failure.

Solid phase detection and identification of HLA antibodies in kidney transplantation currently relies on single antigen bead (Luminex®) assays, which is more sensitive than the previously used enzyme-linked immunosorbent assays (ELISA). To evaluate the impact of more sensitive HLA testing on antibody-mediated rejection (AMR) occurrence and allograft survival, we analysed 1818 renal allograft recipients transplanted between March 2004 and May 2021. In 2008, solid phase testing switched from ELISA to Luminex. We included 393 (21.6%) transplantations before and 1425 (78.4%) transplantations after transition from ELISA- to Luminex-based testing. For this study, bio-banked ELISA era samples were tested retrospectively with Luminex. Significantly less pretransplant DSA were found in patients transplanted with pre-existing HLA antibodies in the Luminex (109/387) versus the ELISA period (43/90) (28% vs. 48%, p < 0.01). Throughout histological follow-up, 169 of 1818 (9.3%) patients developed AMR. After implementing Luminex-based testing, the rate of AMR significantly decreased (p = 0.003). However, incidence of graft failure did not significantly differ between both eras. In conclusion, less patients with pretransplant DSA were transplanted since the implementation of Luminex HLA testing. Transition from ELISA- to Luminex-based HLA testing was associated with a significant decrease in AMR occurrence post-transplantation. Since the decline of AMR did not translate into improved graft survival, Luminex-based testing has the added value of preventing low-risk AMR cases. Therefore, Luminex' high sensitivity must be balanced against waiting time for a suitable organ.

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.

Abstract CT170: Trial in progress: A phase 1, first in human clinical trial for T-Plex, a multiplexed, enhanced T cell receptor-engineered T cell therapy (TCR-T) for solid tumors

Abstract Checkpoint immunotherapies have revolutionized solid tumor treatment yet durably benefit a minority of patients, as they rely on endogenous anti-tumor T cells. A potential solution for patients lacking functional endogenous anti-tumor T cells is engineering their T cells with exogenous T cell receptors (TCRs) to target and kill tumor cells. Initial clinical trials with TCR engineered T cell therapies (TCR-Ts) targeted single tumor antigens on single HLA and produced partial, short-lasting responses. Solid tumors are notoriously heterogenous with highly variable antigen expression. Recent discoveries also identified HLA loss of heterozygosity in up to 40% of solid tumors, allowing tumor cells to evade T cell attack. To overcome this heterogeneity, TScan has developed T-Plex, a multiplexed cell therapy comprising 2-3 different TCR-Ts, chosen from a collection of TCR-Ts called the ImmunoBank, to target different tumor antigens on different HLA types with confirmed tumor expression. To deepen clinical responses, TCR-T cells are engineered to express CD8α/β co-receptors that, in preclinical experiments, enable CD4+ helper T cells to have &amp;gt;100-fold improved cytotoxicity and cytokine secretion over CD4+ cells expressing the TCR alone. Finally, to allow T cell persistence despite immunosuppressive TGF-β in the solid tumor microenvironment, TCR-T cells also express the dominant negative TGF-βreceptor, enabling ~10-fold improved proliferation in the presence of TGF- β compared to T cells expressing the TCR and CD8α/β co-receptors alone. A proprietary transposon vector with larger cargo limit enables the inclusion of these additional genes. The Phase 1 study utilizes a separate screening protocol to pre-identify patients with head and neck, cervical, anogenital cancers, NSCLC, and melanoma, any time during standard clinical care, enabling rapid enrollment into the treatment protocol upon disease progression. Screening comprises germline HLA testing, and archival tumor testing for antigen expression and exclusion of HLA loss. Treatment includes standard non-myeloablative lymphodepletion followed by one or 2 doses of T-Plex infused 28 days apart. Dose escalation under the interval 3+3 design starts with testing single TCR-Ts in dose levels 1 and 2. Thereafter, TCR-Ts are combined and escalated in dose levels 3 and 4. TCR-Ts currently in the master protocol target PRAME, MAGE-A1 or HPV16 on HLA-A*02:01 or MAGE-A1 on HLA-C*07:02. Additional TCR-Ts added to the ImmunoBank and master protocol go through dose levels 1 and 2 as single therapies before becoming available for multiplexed dose levels 3 and 4. Primary endpoints include safety, feasibility and identifying the recommended Phase 2 dose. Secondary endpoints are rates and durations of response and exploratory endpoints measure T cell activation and persistence. Two additional TCR-Ts are on track to be added to the ImmunoBank, which could allow 50-80% of common solid tumor patients to qualify for multiplexed TCR-T therapy. Citation Format: Justin Moser, Brian Pico, Brian Henick, Rom Leidner, Jared Weiss, James Isaacs, Jaspreet Grewal, Michael Hurwitz, Jim Murray, Marlyane Motta, Yun Wang, Shrikanta Chattopadhyay, Debora Barton, Gavin MacBeath, Sajeve Thomas. Trial in progress: A phase 1, first in human clinical trial for T-Plex, a multiplexed, enhanced T cell receptor-engineered T cell therapy (TCR-T) for solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT170.

A177 AUTOIMMUNE ENTEROPATHY – AN UNCOMMON CAUSE OF MALNUTRITION

Abstract Background Autoimmune Enteropathy is a rare condition characterized by clinical symptoms of intractable diarrhea, vomiting, and weight loss that often results in malnutrition. It is associated with other autoimmune conditions from primary sclerosing cholangitis to type 1 diabetes and autoimmune thyroid disease. The epidemiology of AIE in adults is not well described. It is detailed more in the pediatric population, particularly early in life, the incidence is estimated at less than 1 in 100,000 infants. Aims Aims: To review a case of malnutrition secondary to Autoimmune enteropathy seen at our centre, and review the limited literature for treatment. Methods We did a case report presentation on an inpatient seen at our Tertiary care center in Hamilton, Ontario We reviewed the limited literature regarding treatment of autoimmune enteropathy in adults and modelled our treatment based on this. Results We describe the case of a 63-year-old male in Ontario, Canada whereby he was initially diagnosed with ulcerative colitis, but did not respond to therapy – with the final diagnosis being autoimmune enteropathy. He was first consulted to Gastroenterology with colonoscopy consistent with mayo III disease, and biopsies showing chronic active colitis. He did not improve despite 5-ASA compounds, oral steroids, and trials of IV steroids. He underwent multiple admissions for chronic watery diarrhea, and subsequent treatment with IV steroids. He was started on an Infliximab biosimilar with little to no clinical response, and subsequently referral to our centre for evaluation of worsening malnutrition. Our patient’s symptoms mirrored much of what was initially described in the literature in 1985 with significant unremitting diarrhea, and dependence on TPN due to malabsorption. He underwent an EGD which demonstrated villous blunting, and apoptotic bodies – reviewed by a GI-specialized pathologist who found it was consistent with autoimmune enteropathy. His serology testing revealed a weakly positive TTG, HLA testing was completed showed a HLA DQ2 positivity and a gluten free diet was reccomended. His symptoms improved drastically from 10-12 bowels movements daily, to 1-2 daily within two weeks of treatment. The limited literature surrounding treatment of autoimmune enteropathy was reviewed and the patient was started on oral budesonide in a tapering dose with significant clinical improvement as described in a retrospective case-control study in 2017. Conclusions Autoimmune enteropathy is a rare cause of malnutrition in adult patients. It is often associated with other autoimmune conditions, withsmall bowel histology showing villous atrophy, villous blunting, apoptotic bodies, and a relatively low amount of lymphocytic infiltration. The literature on treatment is limited, our patient responded to initial treatment of gluten removal for underlying celiac disease combined with oral budesonide. Funding Agencies None

Transitioning to a New Lab for HLA Testing: Impact on Workflow and Time to Donor Selection

Transitioning to a New Lab for HLA Testing: Impact on Workflow and Time to Donor Selection

O024 Sodium oxybate for refractory narcolepsy and idiopathic hypersomnia: clinical and employment outcomes

Abstract Background Sodium oxybate (SOX) is an evidenced based treatment for narcolepsy. SOX is not available in Australia through the pharmaceutical benefits scheme. In 2018, Western Australia (WA) listed sodium oxybate on the state formulary for the treatment of refractory narcolepsy. We examine the demographics, clinical and employment outcomes of patients treated with SOX. Methods We undertook a retrospective study of patients treated with sodium oxybate in WA for refractory narcolepsy or idiopathic hypersomnia (IH). A database of SOX patients was cross checked with pharmacy prescribing data from across WA public hospitals. Electronic medical records were used to collect demographic, polysomnographic, prescribing and outcome data. Clinical outcomes were based on the Epworth sleepiness scale, clinical assessment and employment status. Patients that responded to SOX are to be compared to non-responders using appropriate statistical methodology. Progress to date The study has been registered as a hospital clinical audit (number 49852). A total of 50 patients prescribed SOX for the treatment of a central hypersomnia have been identified. A request for sodium oxybate dispensing data across WA has been made. Review of 10 patient’s records has been completed. Correspondence, sleep studies, MSLT, HLA testing and prescriptions are being reviewed for the remaining 40 patients. Intended outcome and impact Describe the characteristics of patients treated with SOX in WA. Explore whether clinical or sleep study characteristics predict response to SOX. Assess patient reported outcomes from treatment with SOX based on symptoms and changes in employment status.

Adaptation of HLA testing to characterize the cynomolgus macaque MHC polymorphisms and alloantibody signatures.

Nonhuman primates are the closest animal models to humans with respect to genetics and physiology. Consequently, a critical component of immunogenetics research relies on drawing inferences from the cynomolgus macaque to inform human trials. Despite the conserved organization of the Major Histocompatibility Complex (MHC) between cynomolgus macaques and humans, MHC genotyping of cynomolgus macaques is challenging due to high rates of copy number variants, duplications, and rearrangements, particularly at the MHC class I loci. Furthermore, the limited availability of commercial reagents specific to cynomolgus macaques that can be used to characterize anti-MHC class I and class II antibody (Ab) specificities in cynomolgus macaques presents a major bottleneck in translational research. Here we successfully characterized cynomolgus macaque Mafa class I and class II serologic specificities in 86 animals originating from various geographical regions using the complement dependent cytotoxicity (CDC) assay with human HLA class I and class II monoclonal antibody (mAb) typing trays. Further, we successfully induced and characterized anti-Mafa class I and class II alloantibody specificity using HLA single antigen bead assays. We also subsequently tracked the alloAb burden in the animals during treatment with anti-B lymphocyte stimulator (BLyS) treatment. Altogether, these methods can be easily used in translational research to serotype MHC class I and class II specificity in macaques, characterize their alloAb specificity, and evaluate the efficacy of novel therapeutic modalities in depleting circulating alloAbs in these animals.

A-150 Abo Subgroup Incompatibility Leading to Red Cell Engraftment Failure and Fatal Outcome: A Rare But Preventable Complication in Related Allogeneic HSCT

Abstract Background Pre-allogeneic hematopoietic stem cell transplant (HCST) testing includes, among others, ABO and HLA typing and testing for anti-HLA antibodies. ABO subgroup typing is not routinely performed, as A2 subgroup representes 1% of the total group A population and only 0.4% of A2 individuals have anti-A1 in their serum. ABO antigens are also found on the platelet surface. We describe a case of alloHSCT performed between siblings, the donor A1 and the recipient A2, with a fatal outcome caused by red cell and platelet engraftment failure due to anti-A1 antibodies, and emphasize the need to routinely investigate subgroup incompatibility in the pre-alloHSCT workup. Methods Patient data was collected from hospital and laboratory electronic records. Blood typing and immunohematological investigation was performed at the hospital blood bank using gel cards for ABO typing, DAT and antibody screening panels (Grifols, Barcelona). Tube method was used for A subgroup typing (Fresenius, Germany). Bone marrow analysis and other blood tests were performed at local hospital laboratory. HLA typing and antibody screening (Luminex, USA) were sent to a specialized laboratory. Results A 51 year-old male with Non-Hodgkin lymphoma underwent a full-match ABO compatible allogeneic HSCT, both brother/donor and recipient group A. Pre-transplant anti-HLA or ABO antibodies were negative. WBC recovery was achieved on D + 22. The patient had a catheter infection on D + 15 (Permcath removed), CMV infection on D + 24 (treated with gancyclovir) and received several blood transfusions. On D + 22, he had a hemolytic transfusion reaction with fever (38.5°C), chills and a decline in hemoglobin (7.3 g/dL to 6.6 g/dL in the following day), low haptoglobin and increased indirect bilirrubin levels. Immunohematological investigation revealed a positive DAT with an anti-A antibody in the eluate. Subgroup incompatibility was suspected and the patient was found to be subgroup A2, whereas the donor typed A1. Three days later the DAT became negative and anti-A1 was no longer detected. Other RBC antibodies were also excluded. Only group O RBCs and A / AB platelets were transfused thereafter to prevent further hemolysis. On D + 35 the patient was diagnosed with GI-GVHD, which responded to corticosteroids. He never achieved transfusion independence and received RBC and platelet transfusions on a regular basis. Failure of RBC and platelet engraftment was confirmed by a bone marrow aspirate on D + 45, showing only 20% erythroid lineage and absence of megakaryocytes. Marrow chimerism revealed 83% of donor origin. Sepsis by S. aureus ensued on D + 57 and three days later he had fever (38.2°C) and dyspnea after a platelet transfusion. Despite entubation and mechanical ventilation, he evolved to RCP and died on D + 60. Conclusion ABO subgroup typing is a simple and low-cost technique routinely available in the blood bank. Detection of A subgroup incompatibility impacts on key decisions, such as donor choice (if more than one candidate) and the need for erythrocyte depletion of donor stem cells and recipient plasmapheresis if the anti-A1 titer is high. Since graft failure due to ABO subgroup incompatibility can be hazardous, we recommend routinely ABO subgroup typing in the pre-alloHSCT workup to increase donor safety.

Recurrent MiscarriageGreen-top Guideline No. 17.

In this guideline, recurrent miscarriage has been defined as three or more first trimester miscarriages. However, clinicians are encouraged to use their clinical discretion to recommend extensive evaluation after two first trimester miscarriages, if there is a suspicion that the miscarriages are of pathological and not of sporadic nature. Women with recurrent miscarriage should be offered testing for acquired thrombophilia, particularly for lupus anticoagulant and anticardiolipin antibodies, prior to pregnancy. [Grade C] Women with second trimester miscarriage may be offered testing for Factor V Leiden, prothrombin gene mutation and protein S deficiency, ideally within a research context. [Grade C] Inherited thrombophilias have a weak association with recurrent miscarriage. Routine testing for protein C, antithrombin deficiency and methylenetetrahydrofolate reductase mutation is not recommended. [Grade C] Cytogenetic analysis should be offered on pregnancy tissue of the third and subsequent miscarriage(s) and in any second trimester miscarriage. [Grade D] Parental peripheral blood karyotyping should be offered for couples in whom testing of pregnancy tissue reports an unbalanced structural chromosomal abnormality [Grade D] or there is unsuccessful or no pregnancy tissue available for testing. [GPP] Women with recurrent miscarriage should be offered assessment for congenital uterine anomalies, ideally with 3D ultrasound. [Grade B] Women with recurrent miscarriage should be offered thyroid function tests and assessment for thyroid peroxidase (TPO) antibodies. [Grade C] Women with recurrent miscarriage should not be routinely offered immunological screening (such as HLA, cytokine and natural killer cell tests), infection screening or sperm DNA testing outside a research context. [Grade C] Women with recurrent miscarriage should be advised to maintain a BMI between 19 and 25 kg/m2 , smoking cessation, limit alcohol consumption and limit caffeine to less than 200 mg/day. [Grade D] For women diagnosed with antiphospholipid syndrome, aspirin and heparin should be offered from a positive test until at least 34 weeks of gestation, following discussion of potential benefits versus risks. [Grade B] Aspirin and/or heparin should not be given to women with unexplained recurrent miscarriage. [Grade B] There are currently insufficient data to support the routine use of PGT-A for couples with unexplained recurrent miscarriage, while the treatment may carry a significant cost and potential risk. [Grade C] Resection of a uterine septum should be considered for women with recurrent first or second trimester miscarriage, ideally within an appropriate audit or research context. [Grade C] Thyroxine supplementation is not routinely recommended for euthyroid women with TPO who have a history of miscarriage. [Grade A] Progestogen supplementation should be considered in women with recurrent miscarriage who present with bleeding in early pregnancy (for example 400 mg micronised vaginal progesterone twice daily at the time of bleeding until 16 weeks of gestation). [Grade B] Women with unexplained recurrent miscarriage should be offered supportive care, ideally in the setting of a dedicated recurrent miscarriage clinic. [Grade C].

HLA discordance between blood and tumor: A treatment conundrum?

e21577 Background: Tebentafusp is a bispecific gp100 peptide-HLA-directed CD3 T cell engager that is now FDA approved for HLA-A*02:01 patients with unresectable or metastatic uveal melanoma (UM). Tebentafusp requires the targeted gp100 peptide to be presented by the major histocompatibility complex Class I complex HLA-A*02:01 allele for optimal cell killing. HLA-A*02:01 has been reported to be carried by approximately 50% of the North American and Western European population. The clinical trials for tebentafusp all required central blood tests to determine HLA status. In March of 2021, Caris Life Sciences began the launch of HLA Genotype as a standard reporting element for patient tumors profiled by Caris. Somatic HLA mutations have been described in different tumor types and has strong implications for a possible mechanism of immune evasion. Tumor heterogeneity between tumors and within tumors may also impact HLA tumor testing. As more novel drugs that rely on HLA genotyping are developed, understanding the relationship between blood and tumor HLA testing has become crucial. Methods: A single institution retrospective analysis was performed of patients who had tumor HLA genotyping performed as part of their tumor profiling by Caris Life Sciences. HLA Genotyping by Caris was performed using Whole Exome Sequencing of the tumor. Of the patients who had tumor HLA genotyping results, patients who also had blood HLA typing were identified. The concordance rate of HLA-A status between blood testing and tumor testing was determined. The prevalence of HLA-A*02:01 in our patients was also determined (either blood or tumor). Results: Forty-seven patients with both tumor and blood HLA genotyping were identified (37 UM, 8 cutaneous melanoma, 1 mucosal melanoma, 1 renal cell carcinoma). The majority of the patients were Caucasian (n = 44), with only two Asian patients and one African patient. There were two UM patients whose tumor and blood HLA genotyping were discordant (concordance rate of 95.7%). One patient was found to be HLA-A*01:01, *026:01 by blood but tumor genotyping revealed HLA- A*01:01, A*02:01. The other patient was found to be HLA-A*02:01, A*01 by blood but tumor genotyping revealed HLA-A*03:01, A*33:03. The prevalence of HLA-A*02:01 in the entire group was 34%, while the prevalence of HLA-A*02:01 in the Caucasian patients was 36.4%. None of the non-Caucasian patients were HLA-A*02:01 by blood or tumor genotyping. Conclusions: Among our 47 patients with both tumor and blood HLA genotyping, we found two patients with discordant HLA results. Neither of the discordant UM patients had received tebentafusp yet, but it brings up a crucial question about how these patients may respond to a therapy that relies on the HLA-A*02:01 complex. Our study highlights the importance of continuing to use blood HLA genotyping as the standard test to determine eligibility for a treatment such as tebentafusp, as the concordance rate with tumor genotyping is high but not 100%.

Product characteristics and clinical trial design for T-Plex: Multiplexed, enhanced T cell receptor engineered T cell therapy for solid tumors.

2554 Background: Checkpoint immunotherapies have revolutionized the treatment of solid tumors yet durably benefit a minority of patients because they rely on endogenous anti-tumor T cells. In patients lacking functional anti-tumor T cells, a solution is engineering their T cells with exogenous T cell receptors (TCRs) to efficiently target and kill tumor cells. Initial clinical trials with TCR engineered T cell therapies (TCR-Ts) only produced partial, short-lasting responses because they targeted single tumor antigens. Solid tumors are notoriously heterogenous not only with highly variable antigen expression levels but also with recently identified HLA gene losses occurring in up to 40% of solid tumors, enabling tumor cells to evade T cell attack. Methods: To overcome this heterogeneity, TScan has developed T-Plex, a multiplexed therapy comprising 2-3 different TCR-Ts, chosen from a collection of TCR-Ts called the ImmunoBank, to target different tumor antigens presented on different HLA types with confirmed tumor expression. Results: To deepen clinical responses, TCR-T cells are engineered to express the CD8α/β co-receptors that, in preclinical experiments, enable CD4+ helper T cells to become &gt;100-fold more cytotoxic and secrete cytokines at &gt;100-fold lower target antigen levels. Finally, to enable T cell persistence despite immunosuppressive TGF-β in the tumor microenvironment, engineered TCR-T cells express the dominant negative TGF-β receptor allowing ~10-fold improved proliferation and ~2-fold improved cytokine production in the presence of TGF-β. The inclusion of these additional genes is enabled by a transposon manufacturing system with no cargo limit. Patient selection for the Phase 1 study uses a separate screening protocol to identify patients any time during standard clinical care so they can rapidly enroll into the treatment protocol upon progression. Screening comprises germline HLA testing, then archival tumor testing for antigen expression and HLA loss. Treatment includes standard lymphodepletion followed by 2 doses of T-Plex infused 28 days apart. T-Plex initially starts with 2 TCR-Ts targeting different MAGE-A1 antigens presented either on HLA-A*02:01 or HLA-C*07:02. Dose escalation starts with testing the single TCR-Ts individually in dose levels 1 and 2. The two TCR-Ts will then be combined and escalated in dose levels 3 and 4. Additional TCR-Ts added to the ImmunoBank will go through dose levels 1 and 2 as single therapies before becoming available for multiplexed dose levels 3 and 4. Primary endpoints include safety and feasibility, secondary endpoints are response rates and duration of response and exploratory endpoints measure T cell persistence. Conclusions: Four additional TCR-Ts are on track to be added to the ImmunoBank in 2023 which makes 50-80% of patients with common solid tumors eligible for multiplexed TCR-T therapy.

0984 Near Drowning: A Complex Case of Somnolence and Weakness

Abstract Introduction Narcolepsy is a disorder of sleep characterized by pathologic daytime sleepiness classically divided into two major subtypes – those with or without cataplexy. The underlying pathophysiologic mechanism is thought to be related to hypocretin/orexin; pathologically low levels of hypocretin characterize narcolepsy with cataplexy. We present a complex case of weakness in a patient evaluated for narcolepsy. Report of case(s) A 38 year-old male with a BMI of 33 presented with a decade of daytime sleepiness and sudden debilitating attacks of muscle weakness. He underwent level III home sleep testing revealing a respiratory event index of 5.3/h. After an unsuccessful trial of mandibular advancement, he was started on positive airways pressure (PAP) but continued to experience daytime sleepiness and episodes concerning for cataplexy including sensation of legs feeling stiff and falling with stress. He also described episodes of weakness while swimming with inability to stand or stabilize, prompting evaluation for narcolepsy with cataplexy. Sleep diary showed average nightly sleep of 6.5 hours, low sleep latency, and refreshing napping. He underwent PSG while using CPAP 8 cm H2O showing AHI 0.2/h, sleep time 6.2 hours, sleep latency 5.5 minutes and REM latency 33 minutes with evidence of REM sleep without atonia. He underwent MSLT showing a mean sleep latency of 7.6 minutes and 3/5 REM sleep onset periods. Therapeutic trials of venlafaxine and pitolisant did not result in symptomatic improvement, and further genetic testing with HLA DQB-1 was negative. CSF hypocretin measurement was normal (329 pg/mL, reference &amp;gt; 200 pg/mL). These effectively ruled out cataplexy as the cause of his weakness. He continued on PAP therapy, venlafaxine, and modafinil 200 mg for hypersomnia/narcolepsy without cataplexy with good response. Conclusion We present a complex case highlighting the utility of HLA and confirmatory CSF testing in the evaluation of cataplexy with episodes of acute weakness accompanying stress and strong emotion, with particularly dangerous events during swimming. Due to lack of therapeutic response despite positive MSLT, further testing with HLA and CSF hypocretin were pursued. This case highlights the limitations of history alone in the diagnosis of cataplexy, and the utility of advanced testing. Support (if any)

HLA alleles and antiseizure medication-induced cutaneous reactions in Brazil: A case-control study.

In this observational case-control study, 107 cutaneous adverse reaction (CAR) cases (CAR+) manifesting up to 12 weeks after the start of treatment with antiseizure medication (ASM) were identified. Control groups consisted of 98 epilepsy patients without a history of CAR (CAR-) and 3965 healthy individuals in the Brazilian National Registry of Bone Marrow Donors. All participants were HLA typed by high-resolution Next Generation Sequencing for HLA-A, B, C, DQB1 and DRB1; HLA-DPA1, DPB1, DQA1, DRB3, DRB4 and DRB5 were also sequenced in samples from CAR+ and CAR- individuals. The relationship between the carrier frequency of each allele, CAR type and ASM for all participants was investigated. The ASMs most frequently associated with CAR were carbamazepine (48% of CAR+ subjects), lamotrigine (23%), phenytoin (18%), phenobarbital (13%) and oxcarbazepine (5%). The main alleles associated with a risk of CAR were HLA-A*02:05 (OR = 6.28; p = 0.019, carbamazepine or oxcarbazepine); HLA-DPA1*02:02 (OR = 4.16, p = 0.003, carbamazepine); HLA-B*53:01 (OR = 47.9, p = 0.014, oxcarbazepine), HLA-DPA1*03:01/DPB1*105:01 (OR = 25.7, p = 0.005, phenobarbital); HLA-C*02:10 (OR = 25.7, p = 0.005, phenobarbital) and HLA-DRB1*04:02 (OR = 17.22, p = 0.007, phenytoin). HLA-A*03:01 increased the risk for phenytoin-induced maculopapular exanthema 4.71-fold (p = 0.009), and HLA-B*35:02 was associated with a 25.6-fold increase in the risk of carbamazepine-induced Stevens-Johnson syndrome (p = 0.005). None of the 4170 subjects carried the HLA-B*15:02 allele, and HLA-A*31:01 was not associated with CAR. Hence, HLA-A*31:01 and HLA-B*15:02 were not associated with CAR in this population. Although other HLA class I and II alleles tested were associated with a risk of CAR, none of these associations were strong enough to warrant HLA testing before prescribing ASM.

Популяционное исследование распространенности целиакии среди школьников г. Москвы

Objective. Examination of schoolchildren in Moscow using a specially designed questionnaire to identify children at risk of developing celiac disease. Patients and methods. The study enrolled 3070 Moscow schoolchildren aged 7–18 years old. Serological and genetic examinations were performed in 42 children at risk for celiac disease, including determination of IgA and IgE to wheat, IgA and IgG to tissue transglutaminase, and IgA to endomysium. Molecular HLA testing for alleles that predispose to celiac disease was conducted. Endoscopic and morphological diagnostics were performed when indicated. Results. The risk group for celiac disease amounted to 10.2% of all schoolchildren surveyed. According to the results of the questionnaire, children in the risk group significantly more often had abdominal pain, excess gas, bloating, flatulence, dyspeptic complaints (diarrhea, constipation, vomiting), asthma attacks or other forms of allergies, headache, joint or body pain, fatigue and weakness, mood swings, depression, anxiety, or episodes of emotional arousal. Changes in height, weight, delayed physical or sexual development, dental enamel defects, and skin rashes were also noted. Of the 42 children in the risk group, the DQ2 heterodimer was detected in 13 (31%) children, the DQ8 heterodimer – in 2 (4.8%), and a combination of DQ2 and DQ8 heterodimers – in 1 (2.4%). Thus, characteristic HLA haplotypes were identified in 38% of the examined children. Three children had IgA antibodies to tissue transglutaminase (at &gt;10 norm) and IgA anti-endomysium antibody titers. Conclusion. The method of questioning by means of a specially designed questionnaire for school-age children allows to identify individuals at risk of developing celiac disease. According to serological, genetic, endoscopic, and morphological investigations, the incidence of celiac disease among children at risk was 7.1%. The prevalence of celiac disease among school-age children in Moscow corresponds to global trends, amounting to 0.7%. Key words: questionnaire, gluten-free diet, cereals, gluten intolerance, celiac disease, children

Has the Time Come for Widespread MHC Class I MICA Genotyping in Solid Organ Transplantation?

Has the Time Come for Widespread MHC Class I MICA Genotyping in Solid Organ Transplantation?

Genotyping for HLA risk alleles versus patch tests to diagnose anti-seizure medication induced cutaneous adverse drug reactions.

Aim: To provide a comparison of genotyping for HLA risk alleles versus patch testing to determine which of these two tests is a better diagnostic tool for cutaneous hypersensitivity reactions caused by anti-seizure medication. Methods: A literature study was performed in PubMed to assess the sensitivity and specificity of HLA genotyping and patch tests for identifying anti-seizure medication induced cutaneous hypersensitivity reactions. Results: This study shows that HLA-B*15:02 genotyping shows high sensitivity for carbamazepine-induced SJS/TEN, especially in Han Chinese and Southeast Asian patients (66.7-100.0%) whereas the sensitivity of patch tests (0.0-62,5%), HLA-A*31:01 (0-50%) and HLA-B*15:11 (18.2-42.9%) are lower. On the contrary, for carbamazepine and phenytoin induced DRESS, patch tests (respectively 70.0-88.9% and 14.3-70.0%) show higher sensitivity than HLA tests (0-66.7% and 0-12.7%). Also for lamotrigine-induced DRESS patch tests perform better than HLA-B*15:02 (33.3-40.0 versus 0%). For anti-seizure medication induced MPE and for oxcarbazepine-induced SCARs more studies are needed. Conclusion: Use of HLA-B genotyping may aid clinicians in the diagnosis of carbamazepine, phenytoin, lamotrigine and oxcarbazepine induced SJS/TEN, particularly in Han Chinese and Southeast Asian patients. On the other hand, patch tests seem to perform better in the diagnosis of carbamazepine and phenytoin induced DRESS.

Hematopoietic Cell Transplantation in First Remission in AML in Mexico: Very Low Rates Derived from Early Relapses and Lack of Access

Background: Acute myeloid leukemia (AML) is the most frequent indication for allogeneic hematopoietic cell transplantation (alloHCT) in the world. According to international recommendations, intermediate and high-risk patients, <75 years and fit should receive consolidation with alloHCT. The role of autologous HCT in AML is less clear. We previously reported in a multicenter retrospective study a very low HCT rate (8.2%) despite most patients being potential candidates. The HCT rates in Latin America are considerably lower than in US or Europe (63.9 vs. 511.2 and 390.0/10 million). The main objective of this study was to analyze the reasons why the patients that were potential HCT candidates were not transplanted. Methods We included the patients from our previous retrospective multicenter registry that were potential HCT candidates considering: AML diagnosis between January 2013 and December 2017, <66 years, candidates for intensive chemotherapy and with intermediate or high cytogenetic risk. We reviewed the charts to collect information about HCT decisions and the factors associated with access to transplantation. Results We included 301 patients from 10 public centers with a median age of 42 years (14-65), 51.8% were women, 93.2% with an ECOG performance status 0-2 and 91% with an HCT-CI <3. The majority (86.7%) were classified as NOS-AML and 11.6% were secondary AML. Considering cytogenetics: 66.5% had an intermediate risk and 33.5% unfavorable risk. Induction related mortality was: 17.6% and 13.5% were primary refractory. The majority of the patients (80%) were treated in centers with a local transplant progarm. HLA testing was performed in 103 patients (34.2%). The main reasons for not performing the tests were: early relapse or primary refractory in 26.3% and lack of access or financial resources in 26.3%. In 7.5% of the cases, the patient refused to be tested. Age >60 years and HCT-CI >3 were associated with a lower likelihood of undergoing HLA matching (OR 0.2 95% CI 0.04-0.69, p=.006 and OR 0.02 95% CI 0.01-0.46, p<.001, respectively), in contrast with the presence of a local transplant program (OR 3.6 95% CI 1.7-7.71, p<.001). An HLA matched sibling-donor was identified in 45.1%, a haploidentical donor in 32.4% and no donor in 22.5% Only 23.6% of the patients had a HCT consultation and only 36 patients (12%) received HCT as consolidation in first remission: 30 alloHCT and 6 autoHCT. Only 47.9% of the patients receiving a transplant consultation were transplanted; 20/37 relapsed before HCT. The patients with a matched sibling-donor had a higher probability to receive consolidation with HCT when compared to patients with haploidentical or no sibling donor: 50%, 15.2% and 13% (OR 6 95% CI 2.3-15.5, p<.001). All patients without a matched or half-matched sibling donor who underwent transplantation received autoHCT. The median time from diagnosis to HCT consolidation was 7.2 months (2.9-25.1 months). A landmark OS analysis since CR showed a significant benefit from HCT (autoHCT or alloHCT): 3-year OS of 76.9% vs. 37.8%; HR 0.3 (0.1-0.6), p=.001. There was no significant difference between autoHCT and alloHCT with a 3-year OS of 83.3% and 75.4%. Discussion Only 12% of the patients that are potentially candidates are actually receiving HCT in Mexico. HLA testing is performed in only one third of the patients. Lack of access or financial resources and relapses before HLA testing or before HCT are the main reasons. The long-term OS of patients receiving HCT in excellent, however there is a clear bias if with consider the patients that had not the chance to reach the transplant due to early relapses. We have a very big challenge in the region, which is to ensure that the majority of patients who are potential candidates for HCT can access it through timely access to HLA testing and early access to alternative donor HCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

LTT and HLA testing as diagnostic tools in Spanish vancomycin-induced DRESS cases: A case-control study.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe T-cell-mediated off-target adverse reaction. DRESS cases caused by vancomycin have often been reported. The HLA-A*32:01 allele has been associated with genetic susceptibility to vancomycin-induced DRESS in US citizens of European descent. We have analyzed the association of the HLA-A*32:01 allele in 14 Spanish DRESS cases in which vancomycin was suspected as the culprit drug, and the lymphocyte transformation test (LTT) as an in vitro assay to evaluate vancomycin sensitization. The results were compared to vancomycin-tolerant control donors. LTT was performed in 12 DRESS cases with PBMCs from resolution samples available and in a group of 12 tolerant donors. ROC curves determined that LTT is a suitable tool to identify patients sensitized to vancomycin (AUC = 0.9646; p < 0.0001). When a stimulation index >3 was regarded as a positive result, contingency tables determined 91% sensitivity, 91.67% specificity, 91% positive predictive value, and 91.67% negative predictive value (p = 0.0001, Fisher's exact test). The HLA A*32:01 allele was determined by an allele-specific PCR assay in 14 cases and 25 tolerant controls. Among the DRESS cases, five carriers were identified (35.7%), while it was detected in only one (4%) of the tolerant donors, [odds ratio (OR) = 13.33; 95% CI: 1.364-130.3; p = 0.016]. The strength of the association increased when only cases with positive LTT to vancomycin were considered (OR = 24.0; 95% CI: 2.28-252.6; p = 4.0 × 10-3). Our results confirm the association of the risk allele HLA-A*32:01 with vancomycin-induced DRESS in Spanish cases, and support LTT as a reliable tool to determine vancomycin sensitization.