Sequence-specific Oligonucleotide Probes Research Articles

A prospective epidemiological investigation of human leukocyte antigen-B*57:01 in HIV-1-infected Moroccan subjects

BackgroundThe occurrence of hypersensitivity reactions to abacavir, a significant adverse effect, affects approximately 5–8% of Caucasians. Multiple studies conducted in diverse populations have underscored the association between Human Leukocyte Antigen-B*57:01 and abacavir-hypersensitivity reactions. In late 2021, the Moroccan National AIDS Program issued new anti-retroviral therapy protocols for HIV management, including abacavir as an option for the first-line ART regimen. However, data regarding the HLA-B*57:01 prevalence of HIV in Morocco is scarce. This study aims to assess the prevalence of HLA-B*57:01 in both HIV-1-infected children and adults in Morocco. MethodsFrom April to December 2022, we screened 292 HIV-1 infected patients, 70 children and 222 adults, for the HLA-B*57:01 allele using sequence-specific oligonucleotide probes reverse hybridization method. The flow cytometry was used to assess the TCD4 lymphocyte count. The virological status was evaluated using quantitative real-time PCR. Sanger sequencing is under process to confirm the results obtained. ResultsOf 292 HIV-1-infected patients, 12 (4.1%) had the HLA-B*57:01 allele (95% CI, 2.1–7.1). 5 of 70 (7.2%) and 7 of 222 (3.2%) of children and adults were respectively, HLA-B*57:01 positive. There was no statistical association between clinical characteristics (TCD4 cell count and VL) and HLA-B*57:01 allele carriage. ConclusionThe prevalence of HLA-B*57:01 in Moroccan patients was 4.1%, comparable with that of other Middle Eastern populations, higher than that in South African populations but lower than that in Caucasians and Southwest Asians. Our findings indicate an urgent need for HLA-B*57:01 screening before abacavir to reduce the risk of hypersensitivity reactions.

Frequencies of HLA-B alleles in Indonesian Malay Ethnic

BackgroundThe HLA-B alleles have been used as a marker to predict drug-induced adverse reactions and as a major contributor to hypersensitivity reactions. We examined the feasibility of HLA-B alleles as pharmacogenomic markers of drug-induced hypersensitivity in an Indonesian Malay Ethnic. MethodsFifty-eight Indonesian individuals of Malay ethnicity were enrolled in this study. HLA-B alleles were determined using reverse sequence-specific oligonucleotide probe coupled with xMAP technology. ResultsHLA-B*15:02 (15.52%), HLA-B*35:05 (9.48%), and HLA-B*07:05 (7.76%) were frequent alleles in the Indonesian Malay ethnic populations. We discovered at least eight pharmacogenomics markers of drug-induced hypersensitivity: HLA-B*15:02, HLA-B*15:21, HLA-B*13:01, HLA-B*35:05, HLA-B*38:02, HLA-B*51:01, HLA-B*57:01, and HLA-B*58:01. HLA-B*15:02 was in the same serotype group with HLA-B*15:21, which is a B-75 serotype associated with genetic predisposition for carbamazepine-induced Stevens–Johnson syndrome and toxic epidermal necrolysis. The Indonesian population, represented by Malay, Javanese, and Sundanese ethnicities, was similar to South East Asian, Han Chinese, and Taiwanese populations based on HLA-B*15:02 frequency as the most common allele found in Malay ethnics. ConclusionWe provided valuable information on the frequency of drug hypersensitivity-associated HLA-B alleles in Indonesian Malay ethnic population, which can improve treatment safety.

Distribution of the Prevalence of Human Leukocyte Antigen (HLA)-B*57:01 Positivity in HIV-1 Infected Individuals and Its Effects on Treatment: Türkiye Map-Buhasder Working Group

Human immunodeficiency virus (HIV)/acquired immundeficiency syndrome (AIDS) is a critical global public health problem that significantly affects both life expectancy and the overall quality of life of individuals in all age groups. The landscape of HIV infection has changed significantly in recent years due to the introduction of effective combination antiretroviral therapies (ART). A key component of first-line ART regimens for HIV treatment is abacavir, a nucleoside HIV reverse transcriptase inhibitor. Although abacavir is effective in suppressing viral replication and managing disease, its clinical utility is overshadowed by the potential for life-threatening hypersensitivity reactions in HLA-B*57:01-positive patients. In our country, local data obtained from various centers regarding the prevalence of HLA-B*57:01 in HIV-1-infected patients are available. In this study, it was aimed to determine the prevalence of the HLA-B*57:01 genotype in HIV-infected patients who were followed up and treated in many regions of our country. This retrospective study consists of the data of the patients aged 18 years and over diagnosed with HIV-1 infection between 01.01.2019 and 31.07.2022. Age, gender, place of birth, mode of transmission of the disease, death status, CD4+ T cell count and HIV RNA levels at the first clinical presentation, HLA-B*57:01 positivity, and the method used, clinical stage of the disease, virological response time with the treatment they received were recorded from the patient files. Data were collected from 16 centers and each center used different methods to detect HLA-B*57:01. These methods were sequence-specific oligonucleotide probe hybridization (SSOP), DNA sequence-based typing (SBT), single-specific primer-polymerase chain reaction (SSP-PCR), allele-specific PCR (AS-PCR) and quantitative PCR (Q-PCR). A total of 608 HIV-infected individuals, 523 males (86%) and 85 females (14%), were included in the study. The mean age of the patients was 36.9 ± 11.9 (18-73) years. The prevalence of HLA-B*57:01 allele was found to be 3.6% (22 patients). The number of CD4+ T lymphocytes in HLA-B*57:01 allele-positive patients was > 500/ mm3 in 10 patients (45.5%), while the number of CD4+ T lymphocytes in HLA-B*57:01 negative patients was > 500/mm3 in 216 patients (36.9%) (p> 0.05). Viral load at the time of diagnosis was found to be lower in patients with positive HLA-B*57:01 allele but it was not statistically significant (p> 0.05). Although different treatment algorithms were used in the centers following the patients, it was observed that the duration of virological response was shorter in HLA-B*57:01 positive patients (p= 0.006). Although the presence of the HLA-B*57:01 allele has a negative impact due to its association with hypersensitivity, it is likely to continue to attract interest due to its association with slower progression of HIV infection and reduced risk of developing AIDS. In addition, although the answer to the question of whether it is cost-effective to screen patients for HLA-B*57:01 before starting an abacavir-containing ART regimen for the treatment of HIV infection is being sought, it seems that HIV treatment guidelines will continue to recommend screening to identify patients at risk in this regard.

Association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women in India

BackgroundHuman leukocyte antigen (HLA) restriction plays an important role in the susceptibility to alloimmunization against red blood cell (RBC) antigens. The prevalence of anti-D alloimmunization in RhD negative pregnancy is still quite high in our population. Thus, we planned this study to determine the association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women. Material and methodsRBC antibody screen (ABS) was performed for RhD negative pregnant women attending the antenatal clinic our institute. Those with a negative result were included in the ‘non-alloimmunized’ (NAL) group (‘Control’ group), while those with anti-D alloantibody on performing antibody identification were included in the alloimmunized (AL) group of the study (n = 50 each). ABS and identification were done using column agglutination technique. The HLA-DRB1 typing was done by Luminex based reverse sequence specific oligonucleotide probing (SSOP) using commercial kits. The HLA-DRB1 allele frequency was compared in both the groups. ResultsThere was a significant difference between the two groups in terms of gravida (p < 0.001) and history of anti-D immunoprophylaxis (p < 0.001). The frequency of HLA-DRB1*03 and HLA-DRB1*04 alleles was significantly higher in the AL group than the NAL group: 40 % versus 18 % [Odds Ratio (OR): 3.04, 95 % CI: 1.21–7.6; p = 0.015] for HLA-DRB1*03 alleles and 18 % versus 4 % (OR: 5.27, 95 % CI: 1.08–25.78, p = 0.025) for HLA-DRB1*04 alleles. ConclusionThe frequency of HLADRB1*03 and HLADRB1*04 alleles was significantly higher in RhD negative pregnant women alloimmunized with anti-D alloantibody.

#5950 MAJOR HLA ALLELE AND HAPLOTYPE FREQUENCIES IN THE MALTESE KIDNEY TRANSPLANT REGISTRY

Abstract Background and Aims The human leukocyte antigens (HLA) are the most diverse and polymorphic genes in the human genome and matching them is of vital importance for maximising the survival of kidney transplants. The Maltese archipelago consists of three inhabited islands in the Mediterranean Sea, with a total population of just over half a million people. HLA polymorphisms in Malta have never been described. The aim of this study was to investigate allelic frequencies and determine the most common haplotypes for major HLA Class I and Class II groups in the Maltese kidney transplant registry. This will hopefully facilitate organ sharing with other European countries and improve the HLA matching for kidney transplant recipients. Method All patients of Maltese ethnicity on the national kidney transplant list between 2018 and 2022 were analysed retrospectively. HLA typing is routinely performed at medium to high resolution using polymerase chain reaction sequence specific oligonucleotide probes and Luminex technology at the HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DQ and HLA-DP loci. Allele and haplotype frequencies were calculated by direct counting and simple percentages. Results A total of 191 patient samples were analysed yielding the following allele types: 16 HLA-A, 31 HLA-B, 17 HLA-C, 15 HLA-DRB1, 6 HLA-DP, 7 HLA-DQ, 5 HLA-DRB3, one HLA-DRB4 and one HLA DRB5. The most frequent allele groups for the HLA-A locus were HLA-A*02 (30.9%), HLA-A*24 (12.0%) and HLA-A*01 (11.8%) whilst for the HLA-B locus these were HLA-B*35 (16.2%), HLA-B*18 (11.5%) and HLA-B*51 (7.1%). The most prevalent allele groups for the HLA-DRB1 locus were HLA-DRB1*11 (24.1%), HLA-DRB1*04 (13.1%) and HLA-DRB1*07 (11.3%). The commonest allele group for each of HLA-C, HLA-DP and HLA-DR loci were HLA-C*07 (23.6%), HLA-DP4 (5.8%), HLA-DQ7 (31.2%) respectively. The five most frequently encountered haplotypes were HLA-A*02-B*13-DRB1*07 (2.1%), HLA-A*02-B*35-DRB1*04 (1.6%), HLA-A*02-B*18-DRB1*10 (1.3%), HLA-A*02-B*35-DRB1*11 (1.3%), HLA-A*24-B*35-DRB1*11 (1.3%). Conclusion This study provides the first data on the Major HLA allele and haplotype frequencies in Maltese kidney transplant candidates. Such data may be crucial in setting up international kidney exchange programmes.

Diagnostic Utility of a Mycobacterium Multiplex PCR Detection Panel for Tuberculosis and Nontuberculous Mycobacterial Infections.

The prevalence of nontuberculous mycobacterial diseases is increasing worldwide, and tuberculosis remains highly prevalent. Rapid and accurate microbial diagnoses of both tuberculosis and nontuberculous mycobacterial infections are required. A novel PCR-reverse sequence-specific oligonucleotide probe (PCR-rSSO) method-based mycobacterial detection panel (Myco-Panel) test was developed for the rapid identification of 30 mycobacterial species and subspecies. Clinical respiratory samples were collected from patients with suspected or confirmed tuberculosis and nontuberculous mycobacterial lung disease and those with other respiratory diseases. Myco-Panel tests were performed on the samples, and liquid mycobacterial culture and identification were performed for reference according to housekeeping gene sequences of mycobacteria in positive culture tubes. Furthermore, to assess the detection performance for several mycobacterial species rarely recovered in Japan, the accuracy of the Myco-Panel test was investigated using stock mycobacterial type strains and clinical isolates. A total of 178 clinical respiratory samples were analyzed. The Myco-Panel and sequence-based identification results for mycobacterial cultures were 83.1% concordant (kappa coefficient, 0.785 [95% confidence interval, 0.716 to 0.854]). The Myco-Panel correctly identified 281 of the 283 type strains and clinical isolates tested. The Myco-Panel test could accurately detect several mycobacterial species from clinical respiratory samples and mycobacterial suspensions. Rapid and accurate identification of pathogens using respiratory samples is possible using the Myco-Panel. IMPORTANCE Species identification is important for the diagnosis of mycobacterial infections and decisions on treatment regimens. The Myco-Panel test accurately detects clinically common mycobacterial species that cause respiratory infections from clinical respiratory samples and mycobacterial suspensions. The rapid identification of multiple mycobacterial species will provide clinically useful information for the management of patients. Although we understand that the current diagnostic criteria require mycobacterial culture results in general for the diagnosis of nontuberculous mycobacterial infection, mycobacterial culture examination is a time-consuming process. The detection of potentially causative agents directly from clinical samples will aid in practical diagnosis and decision-making for rapid treatment initiation. This is a new laboratory method for species identification, and evaluating its performance is important.

KIR genotype and haplotype repertoire in Kuwaiti healthy donors, hematopoietic cell transplant recipients and healthy family members.

The gene complex located on chromosome 19q13.4 encodes the Killer-cell Immunoglobulin-like Receptors (KIRs), which exhibit remarkable polymorphism in both gene content and sequences. Further, the repertoire of KIR genes varies within and between populations, creating a diverse pool of KIR genotypes. This study was carried out to characterize KIR genotypes and haplotypes among 379 Arab Kuwaiti individuals including 60 subjects from 20 trio families, 49 hematopoietic cell transplantation (HCT) recipients and 270 healthy Kuwaiti volunteer HCT donors. KIR Genotyping was performed by a combination of reverse sequence specific oligonucleotide probes (rSSO) and/or Real Time PCR. The frequencies of KIR genes in 270 healthy Kuwaiti volunteer donors were compared to previously reported frequencies in other populations. In addition, we compared the differences in KIR repertoire of patients and healthy donors to investigate the reproducibility of previously reported significant differences between patients with hematological malignancies and healthy donors. The observed frequencies in our cohort volunteer HCT donors was comparable to those reported in neighboring Arab populations. The activating genes KIR2DS1, KIR2DS5 and KIR3DS1 and the inhibitory gene KIR2DL5 were significantly more frequent in patients compared to healthy donors, however, none of the previously reported differences were reproducible in our Kuwaiti cohort. This report is the first description of KIR gene carrier frequency and haplotype characterization in a fairly large cohort of the Kuwaiti population, which may have implications in KIR based HCT donor selection strategies.

The polymorphism of HLA class I and II alleles in Indian patient with thalassemia

Numerous HLA allele relations with various diseases have been observed all over the world, including leukemia, aplastic anemia, and thalassemia. The current study looked at the frequency of HLA A, B, C, DRB1, and DQB1 loci with thalassemia to see if there was a correlation between the HLA allele and the disease. The study involved a total of 200 patients (cases) and 200 healthy people (controls). Using a polymerase chain reaction sequence-specific oligonucleotide probe technique, all of these samples were HLA typed for HLA class I (A, B, C loci) and class II (DRB1 and DQB1 loci). HLA-DRB1*15:02 (p = 0.0395400, OR = 2.288) and DQB1*06:01 (p = 0.00056000, OR = 2.248911) were found to have a positive connection with thalassemia. Whereas, HLA-A*31:01 (p = 0.0361200, OR = 0.202), B*07:02 (p 0.0358530, OR = 0.296), B*08:01 (p = 0.04595400, OR = 0.476), C*07:02 (p = 0.000240000, OR = 0.00001,) and HLA-DQB1*06:03 (p = 0.007966000, OR = 0.395) were seen to be negatively associated. Our findings are the first to indicate an association between thalassemia and HLA alleles (A, B, C, DRB1, and DQB1 alleles) in the Indian population, and they can be used to strengthen thalassemia studies.

HLA and Non-HLA gene polymorphisms in autoimmune hepatitis patients of North Indian adults.

Autoimmune hepatitis (AIH) is a chronic and progressive disease of the liver. This is a multifactorial autoimmune disease with both environmental factors and genetic factors playing a role in its pathogenesis. Certain environmental agents like viruses, drugs, etc., can trigger the disease in a genetically susceptible individual. The present study was aimed to explore the distribution of human leukocyte antigen (HLA)-DRB1, Protein tyrosine phosphatase non-receptor type 22 (PTPN22) and Cytotoxic T-Lymphocyte-associated protein 4 (CTLA-4) polymorphisms in North Indian adult AIH patients and their associations with clinical and pathological characteristics associated with the disease. A total of 147 subjects with 47 cases and 100 healthy controls were enrolled. Diagnosis of AIH was made by Revised International Autoimmune Hepatitis Group scoring system. HLA-DRB1 Typing was done by Luminex-based reverse Sequence-Specific Oligonucleotide Probing (SSOP). Single nucleotide variant (SNV) genotyping for CTLA-4 and PTPN22 was done by simple probe-based SNP arrays. Results indicated SLA positive AIH patients are poor responders to therapy. A significant predispositional association of HLA-DRB1*03 was observed in AIH patients from the North Indian population (p= 0.0001, OR=4.83 (2.30-10.15). The frequency of the GG genotype of CTLA-4 CT 60 was significantly increased in AIH patients compared to controls. Multinomial analysis showed that CTLA-4 CT 60 is an independent predictor for cases.

Role of HLA alleles polymorphism in systemic lupus erythematosus: A prospective study from North India.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder and has complex etiopathogenesis. The most appropriate hypothesis states that genetic susceptibility in the presence of environmental risk factors predisposes to SLE. HLA class II alleles are critical to immune response and are highly polymorphic. Various alleles in HLA-DR and -DQ regions were analyzed in SLE patients and healthy controls to see their role in susceptibility or protection to SLE. This was a prospective observational study, in which a total of 100 SLE patients and 100 controls were analyzed. HLA typing was done by polymerase chain reaction (PCR)-sequence-specific oligonucleotide (SSO) method (SSO probe). DRβ1*0301 was significantly increased in SLE patients when compared to controls and had the highest odds ratio. Other risk factor alleles found to be increased were DRβ1*0701, DQβ1*0202, and DQβ1*0301, which had a significant positive association with SLE, suggesting their role in susceptibility to SLE. In contrast, DRβ1*0401, DRβ1*1401, DRβ1*1404, DRβ1*1501, DQβ1*0501, and DQα1*0201 showed statistically significant reduction in SLE patients, while these were much more common in controls, suggesting their protective role. This study is only the second study in patients from North India and it determines the role of DRβ1*0301, DRβ1*0701, DQβ1*0202, and DQβ1*0301 alleles as risk factors in SLE patients.

Donor-Specific Antibody Detection by Single-Antigen Bead Assay for Renal Transplantation: A 2-Year Experience from South India.

Recipient sensitization against donor human leukocyte antigens (HLA) plays a key role in transplant rejection, and this risk is best minimized by efficient pre transplant antibody detection. Determination of antibody specificity with the highest sensitivity and degree of resolution to the allelic antigen level is achieved by using single-antigen bead (SAB) assay. This study evaluated the correlation of Luminex cross match (LXM) with SAB assay for detection of donor-specific antibodies (DSA). A total of 2075 renal transplant patients were screened for the presence of DSA by LXM, complement-dependent cytotoxicity (CDC) cross match, and 125 patients for SAB from January 2018 to December 2019. There was a male preponderance among recipients (P < 0.0001), and the most affected age group was 21-40 years. HLA typing was done in 550/2075 by DNA PCR-reverse sequence-specific oligonucleotide probes (SSOP) method. HLA DSA by LXM was detected in 16.3% of recipients (338/2075). Majority 180/338 (53.2%) of the patients were class II DSA positive, (P < 0.0001). Among the class II DSA positive patients, 20/180 (11.1%) samples gave false-positive results by LXM. SAB for class I and class II HLA IgG antibodies was done in 125/338 renal transplant recipients, which included 20 recipients with false-positive class II Luminex DSA, to check whether the DSA detected were really donor specific or not. The results showed that although 20/125 patients had some antibodies detected in their serum, they were not against the donor HLA antigens, as per the HLA typing reports of the donors. When compared to SAB assay, LXM showed more discrepant results, particularly to class II DSA. In conclusion, LXM, if used in combination with SAB assay and HLA typing of donors if necessary for virtual cross match, will help in avoiding unnecessary exclusion of donors for renal transplant recipients and also for post transplant monitoring of recipients, especially in cadaveric donor transplants.

New cost-effective human leukocyte antigen testing algorithm for screening of human leukocyte antigen-matched related donor in thalassemia major patient pretransplant workup

Introduction: India has a huge disease burden of thalassemia major with an estimated 40 million carriers and over a million thalassemia major patients. Very few patients are optimally treated, and the standard of care “hematopoietic stem cell transplant” (HSCT) is out of reach for most patients and their families. The cost of HSCT is significant, and a substantial proportion of it goes to human leukocyte antigen (HLA) testing of family members (HLA screening) in hope of getting a matched related donor (MRD) for HSCT. The aim of this study was to establish that a new proposed testing algorithm of HLA typing would be more cost-effective as compared to the conventional HLA screening within MRD families for possible HSCT. Material and Methods: Buccal swab samples of 177 thalassemia patients and their prospective family donors (232) were collected. Using a new HLA testing algorithm, samples were tested for HLA typing in a sequential manner (first HLA-B, then HLA-A, and finally HLA-DR) using the sequence-specific oligonucleotide probe method on the Luminex platform. Results: The new sequential HLA-A, HLA-B, and HLA-DRB1 testing algorithm showed a 49.1% reduction in cost compared to the conventional HLA testing algorithm. Furthermore, 40 patients (22.59%) were found to have HLA-MRD within the family among other samples that were tested. Conclusion: The new HLA testing algorithm proposed in the present study for identifying MRD for HSCT resulted in a substantial reduction in the cost of HSCT workup.

Creation of human hematopoietic chimeric cell (HHCC) line as a novel strategy for tolerance induction in transplantation.

Cell-based and chimerism-based therapies represent a promising approach for tolerance induction in transplantation. We propose a new cell therapy of the ex vivo created human hematopoietic chimeric cells (HHCC) as an alternative approach to bone marrow (BM)-based therapies in support of solid organ and vascularized composite allotransplantation (VCA). This study aimed to characterize in vitro the phenotype, genotype, clonogenic, and tolerogenic properties of HHCC. Thirty ex vivo fusions of CD34+ cells from two unrelated human BM donors were performed. CD34+ cells were stained separately with PKH26 and PKH67 membrane dyes and fused using polyethylene glycol (PEG). Creation of human HHCC and chimeric state was confirmed by flow cytometry (FC), confocal microscopy (CM) and electron microscopy (EM). HHCC's phenotype (CD34, CD133, CD117, CD4, CD19, CD4/CD25) was assessed by FC, viability by Trypan Blue, LIVE/DEAD and apoptosis by AnnexinV/Sytox Blue and TUNEL assay, while mixed lymphocyte reaction (MLR) assay assessed HHCC's immunogenicity and tolerogenic properties. HHCC differentiation, proliferation and clonogenic potential were assessed by the colony forming unit (CFU). Polyploidy was evaluated by fluorescence in situ hybridization (FISH), whereas polymerase chain reaction-reverse sequence-specific oligonucleotide probe (PCR-rSSOP) and short tandem repeats-polymerase chain reaction (STR-PCR) assessed HHCC's genotype, and chimerism. Reverse transcription polymerase chain reaction (RT-PCR) analyzed cytokines secretion [interleukin (IL)-10, transforming growth factor-β (TGF-β) and tumor necrosis factor-α (TNF-α)] up to 14 days post-fusion. FC and CM confirmed creation of HHCC by fusion of CD34+ cells from two unrelated human donors. After fusion, maintenance of hematopoietic markers and increased expression of Treg-cells (CD4/CD25) was confirmed. Moreover, high HHCC viability (99%) and a low apoptosis rate (1.2%) were revealed HHCC presented decreased immunogenicity by MLR, and significant, 40-fold increase of IL-10 the pro-tolerogenic cytokine at 21 days after fusion (RT-PCR) P<0.0001. The number of polyploid cells was negligible (0.48%). PCR-rSSOP of HHCC after fusion confirmed presence of human leukocyte antigen (HLA) class I and class II-alleles and presence of the loci specific for both CD34+ cells BM donors by STR-PCR. We have created a new hematopoietic cell line of HHCC from two unrelated human donors, and have successfully characterized in vitro, viability, phenotype, genotype, clonogenic, and tolerogenic properties of HHCC. These unique immunomodulatory and tolerogenic properties introduce HHCC as a novel therapeutic approach for tolerance induction in VCA and solid organ transplantation.

P8.039: Allele, Genotype and Haplotype Frequencies of the HLA System in the Province of Neuquén, Argentina

Knowledge of the bioanthropological and genetic characteristics of the population in Neuquén is limited. Determination of the allele and haplotype frequencies of the HLA system provides data on genetic variability, susceptibility or resistance to diverse disease, immunological phenomena and contributes to the selection of donors and recipients in organ transplantation. 583 samples from patients attending the histocompatibility laboratory between January 2015 and March 2022 have been analyzed retrospectively. HLA typing of locus A, B and DR has been performed on all patients by using medium resolution ssop methodology (sequence specific oligonucleotide probes). It was observed that, in locus A, the predominant allele was A2, with a frequency of 15.5 (42.8%). It was followed by A68, with a frequency of 12.22 (33.2%) and A24, with a frequency of 6.83 (20.8%). In locus B, the majority alleles were B35 and B39, with a frequency of 2.68 (33.3%). They were followed by B7, with a frequency of 2.89 (13.8%) and B40, with a frequency of 2.68 (12.8%). In locus DR, the most frequent allele was DR4, with a frequency of 20.85 (46,5%). The second most frequent allele was DR11, with 9.23 (20.6%), and finally, DR8, with 9.0 (20%). The most frequent genotype in locus A was A2-A68 (9.77%). In locus B, it was B35-B39 (5.83%) and, in locus DR, it was DR4-DR4 (7.55%). The most frequent haplotypes were A2-B39 (15%) and A68-B39 (13,4%). Regarding loci A-B-DR, the most observed haplotype was A68-B39-DR4 (7.5%). Due to the existing demographic growth in the province, according to the last census, Neuquén received population from the whole country (Argentina) and from South American countries. Even though the most frequent alleles were similar to alleles from other studies conducted, substantial discrepancies were also identified. Thus, considering the great number of native peoples present in Neuquén, using these methodologies for the study of closed populations would be convenient in the future. Baradello Stefano.

HLA-DRB1∗1502 Is Associated With Anti-N-Methyl-D-aspartate Receptor Encephalitis in Thai Children

BackgroundAnti-N-methyl-d-aspartate receptor encephalitis (anti-NMDARE) is one of the most common types of autoimmune encephalitis. Most patients have no apparent immunologic triggers, which suggests a genetic predisposition. This study was conducted to identify human leukocyte antigen (HLA) class II alleles associated with anti-NMDARE in Thai children. MethodsThis case-control study enrolled patients younger than 18 years who were diagnosed with anti-NMDARE between January 2010 and December 2020. A “good outcome” was determined as a patient with a modified Rankin scale score of less than 2 at any follow-up visit. HLA genotypes were determined at four-digit alleles using reverse sequence-specific oligonucleotide probe hybridization. The HLA class II allele frequency in patients was compared with that in a database of 101 healthy control Thai children. ResultsThirty-four patients were enrolled with a mean age of 12.8 ± 5.6 years (females 85.3%). The HLA-DRB1∗1502 allele frequency was significantly higher in patients than in controls (odds ratio, 2.32; 95% confidence interval, 1.11-4.8, P = 0.023). A good outcome was noted in 14 of 14 (100%) HLA-DRB1∗1502-positive patients (median time to a good outcome, 6 months) and 14 of 17 (82.3%) HLA-DRB1∗1502-negative patients (median time to a good outcome, 3 months). Two (11.8%) HLA-DRB1∗1502-positive patients had one relapse each, and six (35.3%) HLA-DRB1∗1502-negative patients had one to three relapses. ConclusionsHLA-DRB1∗1502 was significantly associated with anti-NMDARE in our patients. Most patients had good outcomes. HLA-DRB1∗1502-positive patients tended to require a longer time to achieve a good outcome but had less frequent relapses than HLA-DRB1∗1502-negative patients.

OA35 Efficacy of secukinumab and HLA-B27 subtypes: results from a Phase 3b randomised controlled trial in axial SpA

Abstract Background/Aims Human Leukocyte Antigen (HLA)-B is strongly associated with axial spondyloarthritis (axSpA); over 100 subtypes of HLA-B27 are currently recognized and designated as HLA-B∗2701 to HLA-B∗27106. The association of these subtypes with clinical features of axSpA patients or their response to therapy has not been determined. This post hoc analysis explored the potential association of the HLA-B27 subtypes with the effect of secukinumab in axSpA patients from the SKIPPAIN trial (NCT03136861). Methods SKIPPAIN, a 24-week, randomised, double-blind, placebo-controlled, multicentre trial, enrolled adult axSpA patients with active disease fulfilling ASAS classification criteria (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] score ≥4 and average spinal pain numerical rating scale [NRS] score &amp;gt;4 at baseline) and inadequate response to ≥ 2 NSAIDs for ≥4 weeks. Patients were randomised (3:1) to receive subcutaneous secukinumab 150 mg or placebo weekly followed by every 4 weeks (q4w) starting at Week 4. At Week 8, placebo patients were re-randomised to secukinumab 150 or 300 mg q4w up to Week 24. HLA-B27 subtypes were tested by PCR-reverse sequence-specific oligonucleotide probe on a baseline blood sample. Average spinal pain scores were analysed using a repeated measures analysis of covariance model. Results Overall, 380 patients with axSpA (269 [70.8%] AS; 111 [29.2%] nr-axSpA) were randomised to secukinumab 150 mg (n = 285) or placebo (n = 95). Most patients were HLA-B27 positive in both treatment groups (233 [81.8%] SEC vs 76 [80.0%] placebo). Distribution of HLA subtypes was consistent with what is expected in a typical European population, with HLA-B*27:05:02G as the most common allele (secukinumab 150 mg, n = 172 [60.4%]; placebo, n = 48 [50.5%]). In the HLA-B*27 homozygous group, a higher proportion of patients had uveitis, peripheral arthritis, enthesitis and a family history of spondyloarthritis versus the heterozygous group; disease severity or burden of disease was similar between the two groups. Male predominance was more evident in the HLA-B*27 homozygous group, who were younger by 1 year and reported longer duration of symptoms by an average of 8 months. Disease severity was comparable while disease burden was higher in the B*27:05:02G versus the B27:02:01G heterozygous group. There was a significant least square (LS) mean difference (standard error [SE]) in back pain response between secukinumab and placebo in HLA-B27 positive patients (-0.9 [±0.27], 95% confidence interval [CI] -1.47 to -0.42, P = 0.0004) and HLA-B27 heterozygous (B*27:05:02G) patients (-0.9 [±0.37], 95% CI − 1.62 to -0.17, P = 0.0152), differences in other HLA-B27 subtypes were non-significant. Conclusion Although secukinumab has shown efficacy in both HLA-B27 positive and negative patients, presence of HLA-B27 and homozygosity had a distinct positive effect on response. Further studies or pooled analyses are warranted to investigate associations of HLA-B27 subtypes with the clinical features of axSpA or of less prevalent HLA-B27 subtypes with treatment response. Disclosure H. Marzo-Ortega: Consultancies; AbbVie, Amgen, BMS, Biogen, Celgene, Gilead, Janssen, Lilly, Novartis, Pfizer, Samsung Bioepis, Sanofi-Aventis, UCB. Grants/research support; Amgen, Lilly, Janssen, Pfizer, Sandoz, Sanofi, Galapagos. D. Poddubnyy: Consultancies; AbbVie, Biocad, BMS, Eli Lilly, MSD, Novartis, Pfizer, Samsung Bioepis, UCB, Gilead. Member of speakers’ bureau; AbbVie, BMS, Lilly, MSD, Novartis, Pfizer, UCB. Grants/research support; AbbVie, MSD, Eli Lilly, Novartis, Pfizer. E. Pournara: Shareholder/stock ownership; Novartis. Other; Employee of Novartis. B. Schulz: Other; Employee of Novartis. A. Deodhar: Consultancies; AbbVie, Amgen, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, GSK, Janssen, Novartis, Pfizer, UCB. Member of speakers’ bureau; AbbVie, Amgen, Boehringer Ingelheim, Bristol Myer Squibb, Eli Lilly, GSK, Janssen, Novartis, Pfizer, UCB. Grants/research support; AbbVie, Eli Lilly, GSK, Novartis, Pfizer, UCB. X. Baraliakos: Consultancies; AbbVie, BMS, Celgene, Chugai, Galapagos, Gilead, MSD, Novartis, Pfizer, UCB. Member of speakers’ bureau; AbbVie, BMS, Celgene, Chugai, MSD, Novartis, Pfizer, UCB. Grants/research support; AbbVie, Novartis.

HLA class I and II alleles profile in Indian patients with aplastic anemia

Several HLA allele associations with aplastic anemia have been reported around the world. However, due to a lack of such association studies in the Indian population, the current study looked at the frequency of HLA class I (A, B, and C loci) and II (DRB1 and DQB1 loci) with aplastic anemia to see if there was an association between the HLA allele and the disease. A total of 49 aplastic anemia patients (cases) and 100 healthy participants (controls) were included in the study. All of these samples were HLA typed for HLA-A, -B, -C, -DRB1, and DQB1 loci using a polymerase chain reaction sequence-specific oligonucleotide probe approach. A positive association of HLA-DRB1*15:02 (p = 0.00001269, OR = 4.275), was found with AA. Whereas HLA-C*07:01 (p = 0.0017318, OR = 0.179) and HLA-DQB1*02:01 (p = 0.00017033, OR = 0.371) were found to be negatively associated. Our findings are the first to show an association between class I and II HLA alleles and aplastic anemia in the Indian population, and they can be used to further investigate aplastic anemia studies.

Clinical Impact of KIR2DS3 and KIR2DL3 Genes in Neuroblastoma Patients

Objective: Neuroblastoma is a common fatal tumor of childhood. Natural killer (NK) cells can exert direct cytotoxicity on tumor cells. The killer immunoglobulin-like receptor (KIR) family of NK cell receptors is involved in activation/inhibition of NK cells. In the KIR gene cluster, six of them (3DS1, 2DS1–5) encode receptors triggering activation, while seven of them (3DL1–3, 2DL1–3, 2DL5) encode receptors triggering inhibition. We aimed to assess the distribution of genetic polymorphisms of KIRs on the clinical course of neuroblastoma and provide guidance on potential therapeutic options. Methods: Our study group included 50 neuroblastoma patients and 100 healthy children as controls. Twenty-eight patients were boys, and twenty-two were girls; median age was 36 months. Fourteen patients had stage 1, 2, 3, or 4S disease, and 36 patients had stage 4 disease. Isolated DNA from the peripheral blood was amplified for sequence-specific oligonucleotide probe analysis of 16 KIR genes. The Fisher’s exact test was used to evaluate the variation of KIR gene distribution. Results: All patients had a lower frequency of KIR2DS3 compared to the control group (p = 0.005). Evaluation of individual KIR genes/genotypes in patients with early stages (stage 1, 2, 3, and 4S) versus stage 4 disease revealed that the frequency of KIR2DS3 was increased in early stages (p = 0.023). Inhibitory KIR2DL3 was increased in the patient group compared to controls (p = 0.038). Furthermore, the frequency of KIR2DL3 was higher in stage 4 neuroblastoma patients compared to the patients with early stages (p = 0.023). Conclusion: Our data suggest a role for KIR2DS3 and KIR2DL3 in development of neuroblastoma. Thus, modulation of KIR2SD3 and/or KIR2DL3 expression or function might present a novel therapeutic strategy for neuroblastoma.

Association of single-nucleotide polymorphisms in tumour necrosis factor and human leukocyte antigens genes with type 1 diabetes.

Type 1 diabetes (T1D) is an autoimmune disease characterized by progressive destruction of insulin-producing pancreatic beta cells. This multifactorial disease has a strong genetic component associated with the human leukocyte antigens (HLA) and non-HLA regions. In this study, we compared frequencies of HLA-DRB1 alleles and single-nucleotide polymorphisms (SNPs) associated the genes coding for: toll-like receptors (TLRs), tumour necrosis factor (TNF), interleukin-1 (IL-1), interleukin-1 receptor type 1 (IL-1R1), interleukin-1 receptor antagonist (IL-1RN), interleukin-2 (IL-2) and interleukin-12B (IL-12B), between T1D patients and healthy controls. The aim was to identify frequency differences and linkage between these genetic markers in T1D patients and healthy controls. Twelve SNPs were investigated as follows: rs16944 (IL-1B), rs1143634 (IL-1B), rs1800587 (IL-1A), rs2069762 (IL-2), rs3212227 (IL-12B), rs2234650 (IL-1R1), rs315952 (IL-1RN), rs3804099 (TLR2), rs4986790 (TLR4), rs4986791 (TLR4), rs1800629 (TNF) and rs361525 (TNF). TaqMan genotype assay method was used for SNPs genotyping. HLA-DRB1* genes were typed by Sequence Specific Oligonucleotide Probe (SSOP). SPSS and SNPStats programs were used for the statistical analysis. Significant differences between T1D and control groups were found for the dominant model of rs361525 and rs1800629A:rs361525G genotypes for TNF. Increased frequencies of DRB1*03 and DRB1*04 and decreased frequencies of DRB1*07, DRB1*11 and DRB1*13 and DRB1*15 were observed in T1D patients compared with controls. However, the genotype, DRB1*07 with rs1800629A/G was associated with T1D. We have confirmed that DRB1*03 and DRB1*04 are associated with increased risk and DRB1*07, DRB1*11 and DRB1*13 and DRB1*15 with decreased risk of T1D. Also, the dominant model of rs361525A, and the rs1800629G:361525A genotype were associated with increased risk. The simultaneous presence of DRB1*07 and rs1800629A/G genotypes in 23 out of 27 DRB1*07 positive T1D patients implied that islet cell peptide processing may have been biased towards autoimmunity by upregulation of TNF associated intronic SNPs.

Human leucocyte antigen association of patients with Stevens-Johnson syndrome/toxic epidermal necrolysis with severe ocular complications in Han Chinese

Background/aimsStevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) induced by cold medicine (CM) may result in severe ocular complications (SOCs). The purpose of this study was to investigate the human leucocyte antigen (HLA)...