Human Leukocyte Antigen Antigens Research Articles

Peculiarities of phenotypes of patients with pyelo- and glomerulonephritis by HLA distribution analysis

Studies devoted to the role of human leucocyte antigens (HLA) in pathogenesis of chronic kidney disease (CKD) have demonstrated the associative links of the HLA antigens, which stipulate the relative and attributive risks of some autoimmune diseases, with immune disorder and a high production of pro-inflammatory cytokines.
 The aim of our study was to determine the peculiarities of phenotypes of CKD patients according to the distribution of HLA-A, B and DR antigens and to conduct their comparative analysis in patients with pyelonephritis (PN) and glomerulonephritis (GN).
 Methods: The distribution of HLA-A, B, DR antigens in 384 CKD patients (120 with PN and 264 with GN) was analyzed. HLA antigens were defined using a standard microlymphocytotoxic test on the Terasakiґs planchette with special panels of anti-HLA serums (20 antigens of locus A, 31 – B and 9 – DR). The control group consisted of 350 healthy donors.
 The HLA antigen frequencies in normal and diseased subjects were compared taking each antigen separately, using χ2 test. The etiologic fraction (attributive risk s > 0,1) was counted using the formula: s = x - y/I- y, where x is frequency of antigen in patients and y is frequency in healthy. The s reading was considered reliable when it exceeded 0.1.
 Results. The causal role (σ > 0,1) was determined for А10, А11; В14, В16 for PN; antigens-protectors - А2, В21, В35, В40.
 For CGN, NS the relative risk is high (RR > 2) at the presence of HLA-A23, А24, А28; B8, В38, В41, В44; DR1, DR4, DRw52 in phenotype, the causal role in etiopathology (σ>0.1) is indicated for A24,А28; B8; DR1, DR4, DRw52; the disease protectors are B12 and B16.
 Conclusion. Conclusion. The features of the HLA-phenotype of patients with pyelo- and glomerulonephritis were shown. It allowed to establish the interconnectedness of the antigens of the histocompatibility complex with the risk of kidney diseases developing, which could help to personificate of the treatment and predicte of the course of the disease.

Deep learning using tumor HLA peptide mass spectrometry datasets improves neoantigen identification.

Neoantigens, which are expressed on tumor cells, are one of the main targets of an effective antitumor T-cell response. Cancer immunotherapies to target neoantigens are of growing interest and are in early human trials, but methods to identify neoantigens either require invasive or difficult-to-obtain clinical specimens, require the screening of hundreds to thousands of synthetic peptides or tandem minigenes, or are only relevant to specific human leukocyte antigen (HLA) alleles. We apply deep learning to a large (N = 74 patients) HLA peptide and genomic dataset from various human tumors to create a computational model of antigen presentation for neoantigen prediction. We show that our model, named EDGE, increases the positive predictive value of HLA antigen prediction by up to ninefold. We apply EDGE to enable identification of neoantigens and neoantigen-reactive T cells using routine clinical specimens and small numbers of synthetic peptides for most common HLA alleles. EDGE could enable an improved ability to develop neoantigen-targeted immunotherapies for cancer patients.

Analysis on polymorphism of high-resolution HLA-A, -B, -C, -DRB1 and -DQB1 in hematopoietic stem cells donors of Chinese Han population from Southern China

Objective To explore the human leukocyte antigen (HLA)-A, -B, -C, -DRB1 and -DQB1 high-resolution alleles polymorphism in hematopoietic stem cells donors of Chinese Han population from Southern China. Methods A total of 4 262 cases hematopoietic stem cell donors of chinese Han population in Shenzhen China Marrow Donor Program (CMDP) from January 2016 to December 2017 were selected as subjects. HLA-A, -B, -C, -DRB1 and -DQB1 loci for high resolution typing of these 4 262 cases hematopoietic stem cell donors were detected by PCR-sequence-specific oligonucleotide probes (SSO) and next-generation sequencing (NGS) analysis. The frequencies of common, well-documented and rare alleles were studied by direct counting method. The χ2 test was used to determine whether the distribution of HLA-A, -B, -C, -DRB1 and -DQB1 alleles of these 4 262 cases hematopoietic stem cell donors accorded with the Hardy-Weinberg equilibrium. Results ① Compared observed values of HLA-A, -B, -C, -DRB1 and -DQB1 alleles in these 4 262 cases hematopoietic stem cell donors of Chinese Han population from Southern China with the expected values, there were not statistically significance (χ2=295.068, 572.482, 355.205, 362.584, 312.150; P>0.05), which indicated that the distribution of HLA-A, -B, -C, -DRB1 and -DQB1 alleles of all hematopoietic stem cell donors in this study conformed with Hardy-Weinberg equilibrium. ② The alleles of HLA-A, -B, -C, -DRB1 and -DQB1 loci in 4 262 cases hematopoietic stem cells donors of Chinese Han population from Southern China were 49, 97, 37, 48 and 22, respectively. Among them, the common alleles with frequencies higher than 0.05 included HLA-A*11∶01, 24∶02, 02∶07, 02∶01, 33∶03 and 02∶03; HLA-B*40∶01, 46∶01, 58∶01, 13∶01 and 51∶01; HLA-C*01∶02, 07∶02, 03∶04, 08∶01, 03∶02, 06∶02 and 03∶03; HLA-DRB1*09∶01, 15∶01, 12∶02, 07∶01, 08∶03, 03∶01, 11∶01 and 04∶05; and HLA-DQB1*03∶01, 03∶03, 06∶01, 05∶02, 03∶02, 02∶01, 05∶03, 06∶02 and 02∶02. For each of the locus, the cumulative allele frequencies of common alleles were 0.767 1, 0.471 6, 0.782 5, 0.656 4 and 0.877 6, respectively. ③ The well-documented and rare alleles of HLA-A, -B, -C, -DRB1 and -DQB1 loci were detected as 22, 42, 14, 11 and 7. Among them, the rare alleles of HLA-A*29∶03; HLA-B*18∶04, 15∶296 and 54∶03; HLA-C*12∶12; HLA-DRB1*04∶101 and HLA-DQB1*02∶10 were not included in the Common Alleles and Well-Documented Alleles (CWD) v2.3 of CMDP. Conclusions Relatively complete high-resolution allelic distribution data of HLA-A, -B, -C -DRB1 and -DQB1 loci in hematopoietic stem cells donors of Chinese Han population from Southern China were obtained in this study. And HLA well-documented and rare alleles were recorded. The results of this study contribute to the accumulation on population distribution and polymorphism data of HLA gene in hematopoietic stem cell donors, and provide reference for improving CWD of CMDP. Key words: HLA antigens; Alleles; Gene frequency; Polymerase chain reaction; High resolution genotyping; Common alleles; Well-documented alleles; Rare alleles; Polymerase chain reaction-sequence-specific oligonudeotide; Next-generation sequencing

Human leukocyte antigen antibody detection technologies in platelet transfusion refractoriness, with special emphasis on functional test

In the clinical settings of transfusion medicine, human leukocyte antigen (HLA) antibody detection and platelet cross-matching are important tests applied in the management of patients with platelet transfusion refractoriness (PTR). Presently, fluorescence beads technologies using extracted and purified HLA antigens are applied for the HLA antibody screening, and highly sensitive methods such as flow cytometry crossmatch (FCXM) and immunocomplex capture fluorescence analysis (ICFA), based on the use of live intact cells, are used for the cross-matching. Such highly sensitive methods have importantly contributed for the prevention of refractoriness caused by low titer antibodies but, on the other hand, they also detect those low titer antibodies or naturally occurring antibodies without or with unknown clinical relevance. Moreover, the use of recombinant antigens has been shown to be associated with specific issues. In addition, although the relationship between the antibody features and the clinical implications, such as the relevance of antibody subclass in platelet clearance, has been investigated in the field of transplantation, presently, few evidence exists in the literature related to blood transfusion. Here, we reviewed on the available HLA antibody detection methods, the issues of the present methods, and present a new method for the evaluation of clinically significant HLA antibodies using in vitro platelet phagocytosis assay.

Analysis of allelic drop-out at autosomal short tandem repeat loci in composite amplification

Objective To investigate the characteristics and causes of allelic drop-out at the autosomal short tandem repeat (STR) loci, and to explore the confirmation strategy of suspected mutations at the STR loci alleles in paternity. Methods From January to June 2017, nine family members from 3 families of three-banded patterns at Shenzhen Blood Center were selected as subjects. Subject inclusion criteria: subjects′ initial test results of the STR loci alleles did not conform to the Mendels laws of genetics, which were suspected allelic drop-out at STR loci. GlobalFiler™ Express kits from ABI, USA were initially used to detect genotype of 21 autosomal STR loci alleles from all blood spot samples. All blood spot samples suspected for having allelic drop-out were verified with the PowerPlex® 21 kits from Promega, USA. Supplemental experiment was used human leukocyte antigen (HLA)-A/-B/-C/-DR/-DQB1 loci genotype test results with PCR-sequence-based typing (SBT) method, and then the haplotype of the subjects was deduced by the family analysis to complete the individual identification verification. This study met the requirements of World Medical Association Declaration of Helsinki revised in 2013. Informed consent was obtained from every subject. Results ① In this study, the allelic drop-out in 6 subjects occurred in 3 STR loci of CSF1PO, D1S165 and TH01, respectively, and the number of mutation steps were different. These allelic drop-out could be either paternal or maternal. ② In family 1, the initial test result of CSF1PO locus was homozygous in both mother and child. The verification test result of CSF1PO locus was heterozygous, and allelic drop 10-locus were confirmed. ③ In family 2, the initial test result of D1S165 locus was homozygous in both child and father. The verification test result of D1S165 locus was heterozygous, and allelic drop-out 16-locus was confirmed. ④ In family 3, the initial test result of TH01 locus was homozygous in both the mother and child. The verification test result of TH01 locus was heterozygous, and allelic drop-out 9-locus was confirmed. ⑤ Twelve HLA-A/-B/-C/-DRB1/-DQB1 loci haplotypes were detected in the DNA samples of 9 subjects, and the HLA locus haplotypes were detected in accordance with Mendels laws of genetics. Conclusions For the suspected STR allelic mutations in STR composite amplification, a single test has the possibility of allelic drop-out risk. Different kits could be used to verify the authenticity of allele mutations, and more reliable results could be obtained. Key words: Loss of heterozygosity; Alleles; Tandem repeat sequences; HLA antigens; Paternity

Regulatory CD4+ T Cells Recognize Major Histocompatibility Complex Class II Molecule-Restricted Peptide Epitopes of Apolipoprotein B.

CD4+ T cells play an important role in atherosclerosis, but their antigen specificity is poorly understood. Immunization with apolipoprotein B (ApoB, core protein of low density lipoprotein) is known to be atheroprotective in animal models. Here, we report on a human APOB peptide, p18, that is sequence-identical in mouse ApoB and binds to both mouse and human major histocompatibility complex class II molecules. We constructed p18 tetramers to detect human and mouse APOB-specific T cells and assayed their phenotype by flow cytometry including CD4 lineage transcription factors, intracellular cytokines, and T cell receptor activation. Apolipoprotein E-deficient ( Apoe-/-) mice were vaccinated with p18 peptide or adjuvants alone, and atherosclerotic burden in the aorta was determined. In human peripheral blood mononuclear cells from donors without cardiovascular disease, p18 specific CD4+ T cells detected by a new human leukocyte antigen-antigen D related-p18 tetramers were mostly Foxp3+ regulatory T cells (Tregs). Donors with subclinical cardiovascular disease as detected by carotid artery ultrasound had Tregs coexpressing retinoic acid-related orphan receptor gamma t or T-bet, which were both almost absent in donors without cardiovascular disease. In Apoe-/- mice, immunization with p18 induced Tregs and reduced atherosclerotic lesions. After peptide restimulation, responding CD4+ T cells identified by Nur77-GFP (green fluorescent protein) were highly enriched in Tregs. A new mouse I-Ab-p18 tetramer identified the expansion of p18-specific CD4+ T cells on vaccination, which were enriched for interleukin-10-producing Tregs. These findings show that APOB p18-specific CD4+ T cells are mainly Tregs in healthy donors, but coexpress other CD4 lineage transcription factors in donors with subclinical cardiovascular disease. This study identifies ApoB peptide 18 as the first Treg epitope in human and mouse atherosclerosis.

How the definition of acceptable antigens and epitope analysis can facilitate transplantation of highly sensitized patients with excellent long-term graft survival.

Highly sensitized patients awaiting a renal transplant have a low chance of receiving an organ offer. Defining acceptable antigens and using this information for allocation purposes can vastly enhance transplantation of this subgroup of patients, which is the essence of the Eurotransplant Acceptable Mismatch program. Acceptable antigens can be determined by extensive laboratory testing, as well as on basis of human leukocyte antigen (HLA) epitope analyses. Within the Acceptable Mismatch program, there is no effect of HLA mismatches on long-term graft survival. Furthermore, patients transplanted through the Acceptable Mismatch program have similar long-term graft survival to nonsensitized patients transplanted through regular allocation. Although HLA epitope analysis is already being used for defining acceptable HLA antigens for highly sensitized patients in the Acceptable Mismatch program, increasing knowledge on HLA antibody - epitope interactions will pave the way toward the definition of acceptable epitopes for highly sensitized patients in the future. Allocation based on acceptable antigens can facilitate transplantation of highly sensitized patients with excellent long-term graft survival.

Predicting Antigen Presentation-What Could We Learn From a Million Peptides?

Antigen presentation lies at the heart of immune recognition of infected or malignant cells. For this reason, important efforts have been made to predict which peptides are more likely to bind and be presented by the human leukocyte antigen (HLA) complex at the surface of cells. These predictions have become even more important with the advent of next-generation sequencing technologies that enable researchers and clinicians to rapidly determine the sequences of pathogens (and their multiple variants) or identify non-synonymous genetic alterations in cancer cells. Here, we review recent advances in predicting HLA binding and antigen presentation in human cells. We argue that the very large amount of high-quality mass spectrometry data of eluted (mainly self) HLA ligands generated in the last few years provides unprecedented opportunities to improve our ability to predict antigen presentation and learn new properties of HLA molecules, as demonstrated in many recent studies of naturally presented HLA-I ligands. Although major challenges still lie on the road toward the ultimate goal of predicting immunogenicity, these experimental and computational developments will facilitate screening of putative epitopes, which may eventually help decipher the rules governing T cell recognition.

Monocyte human leukocyte antigen - Antigen D related, neutrophil oxidative burst and cytokine analysis in patients of decompensated cirrhosis with and without acute-on chronic liver failure.

Background and aimDue to a dysregulated immune response, patients with acute-on-chronic liver failure (ACLF) have increased risk of infection and multi organ failure in comparison to compensated cirrhosis. The comparative data on the presence of ‘immune paresis’ in patients with ACLF and decompensated cirrhosis without ACLF is not available. Aim of the present study was to compare the immunological parameters in patients with decompensated cirrhosis with and without ACLF.MethodologyIn a prospective study, 76 patients with decompensated cirrhosis with (n = 38) and without (n = 38) ACLF and 10 healthy controls (HC) were evaluated for monocytic human leukocyte antigen–antigen D Related (HLA-DR) expression, mean density of HLA-DR expressed on the surface of these cells, neutrophil oxidative burst (NOB) capacity and serum levels of cytokines (IL-1, IL-6, IL-8, IL10, IL-12, and TNF-α).ResultsPatients of decompensated cirrhosis with and without ACLF demonstrated significantly lower mean percentage of monocytes expressing HLA-DR and quantitative increase in the NOB after stimulation with PMA when compared to HC. However there was no difference in mean percentage of monocytes with HLA-DR expression (43.61±26.56% vs. 43.10±20.98%) (p = 0.91), mean density of HLA-DR expression on the surface (30.34±29.32 vs. 41.71±52.13) (p = 0.42) and quantitative increase in NOB after stimulation with PMA (16.55±11.91 vs. 17.24±16.18) (p = 0.47) amongst patients with decompensated cirrhosis with and without ACLF. Patients with ACLF had significantly higher pro-inflammatory and anti-inflammatory cytokines in comparison to patients with decompensated cirrhosis without ACLF.ConclusionPatients with decompensated cirrhosis demonstrate a component of immune-paresis, however there is similar impairment in HLA–DR expression and NOB capacity in patients with and without ACLF. Both inflammatory and anti-inflammatory cytokines are increased in patients with ACLF in comparison to patients with decompensated cirrhosis without ACLF.

The Outcome of Kidney Transplant Recipients Who Had Combined ABO Incompatibility and Preformed Antibody Against Donor HLA Antigen

IntroductionAdvances in desensitization therapy and immunosuppressants made kidney transplantation possible in a recipient who had incompatible blood type with donor or preformed antibody against donor human leukocyte antigen (HLA). However, we can`t guarantee the outcome who has these immunologic r

Generation of tolerogenic dendritic cells using Lactobacillus rhamnosus and Lactobacillus delbrueckii as tolerogenic probiotics.

Systemic lupus erythematosus (SLE) concurs with excessive uncontrolled inflammatory immune responses that lead to the loss of immune tolerance. Dendritic cells (DCs) are important and determinant immune cells that regulate immune responses. Tolerogenic DCs with regulatory markers and cytokines could induce regulatory immune cells and responses. Tolerogenic probiotics are capable of producing regulatory DCs from monocytes in in vitro conditions. The purpose of this study was to evaluate the effect of Lactobacillus delbrueckii and Lactobacillus rhamnosus on the production of DCs in an in vitro condition. Peripheral blood mononuclear cellswere isolated from the healthy and SLE donors. Monocytes were cultured with optimized concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4) to produce immature DCs (IDCs). An IDC uptake assay was performed, and IDCs of healthy and SLE donors were divided into three subgroups following 48 hours of treatment with GM-CSF and IL-4, along with L. delbrueckii, L. rhamnosus, and mixed probiotics for the production of tolerogenic DCs. The surface expression of Human Leukocyte Antigen-antigen D Related (HLA-DR), CD86, CD80, CD83, CD1a, and CD14 was analyzed using flow cytometry, and the gene expression levels of indoleamine 2,3-dioxygenase (IDO), IL-10, and IL-12 were measured using real-timepolymerase chain reaction. We observed significantly reduced expression of costimulatory molecules and other surface markers in the probiotic-induced mature DCs (MDCs) in both healthy and SLE donor groups in comparison with lipopolysaccharide (LPS)-induced MDCs. In addition, the expression of IDO and IL-10 increased, whereas IL-12 decreased significantly in probiotic-induced MDCs compared with LPS-induced MDCs. IDCs and especially mature tolerogenic DC of SLE patients highly expressed IDO. The results of the current study suggested that live probiotics could modify properties of DCs to modulatory cells, which might contribute to the induction of tolerance and renovation of immune hemostasis.

Altered cortical thickness related to single nucleotide polymorphisms in the human leukocyte antigen in antipsychotic-naive schizophrenia

Objective To explore the relationship between changes in cortical thickness and single nucleotide polymorphisms(SNPs) in the human leukocyte antigen(HLA) in a group of antipsychotic-naive schizophrenia (AN-SCZ) patients. Methods Twenty-five chronically ill AN-SCZ patients and 51 healthy controls (HCs) were recruited and studied from May 2014 to July 2016. All participants received 3.0 T MR head scans and blood collection to obtain high resolution T1WI images and detailed genetic data. Next, we extracted and averaged the values of cortical thickness from each brain region(n=68) for each participant by FreeSurfer and then used general linear models to explore the relationship of each SNP with cortical thickness in the AN-SCZ and HCs while including age, gender and duration of disease in the models as covariates. In the next step, we applied an independent-samples t-test with a threshold of 0.05 to explore whether the cortical thicknesses differed significantly between the AN-SCZ and HCs in the brain regions that were significantly associated with the SNPs in the MHC. Finally, we examined the correlation of clinical symptoms with cortical thickness in the above brain areas in the whole AN-SCZ group using Pearson correlation tests. Results Seven of the 11 SNPs within the HLA regions exhibited significant associations with the cortical thickness only in the AN-SCZ patients, including rs1635, rs1736913, rs2021722, rs204999, rs2523722, rs3131296 and rs9272105. Furthermore, the AN-SCZ patients also exhibited significant reductions in cortical thickness in the above brain regions, which included the left entorhinal cortex, the left pars triangularis cortex, the left rostral middle frontal cortex, the right lateral occipital cortex, the right medial orbitofrontal cortex, the gray matter surrounding the right calcarine gyrus, the right rostral middle frontal cortex, the right frontal pole and the caudal part of the right anterior cingulate. The left entorhinal region also exhibited a negative correlation with PANSS activation scores in the AN-SCZ(r=-0.601, P=0.03). Conclusion The present study provided evidence for the significant association of HLA risk variants with cortical thickness in AN-SCZ. Key words: Schizophrenia; Magnetic resonance imaging; Polymorphism, single nucleotide; HLA antigens

Human Leukocyte Antigen: Class I Allele Frequencies and Haplotype Distributionin a Tertiary Care Hospital in Bangladesh

Human leukocyte antigen (HLA) are cell surface glycoproteins encoded by Major Histocompatibility Complex (MHC) geneof human genome. HLA antigen frequency and haplotype distribution are useful for determining disease associations, origin, migration and genetic relationships between populations and predicting the outcome of transplantation. Thus, the present study was carried outto identify HLA class I (HLA-A and HLA-B) antigen and haplotype distribution among a selected Bangladeshi population. This retrospective study was conducted among 1070 individuals who were referred by cliniciansfor HLA typing at the Tissue Typing Laboratory of the Department of Virology, Bangabandhu Sheikh Mujib Medical University (BSMMU) during the period 2009 to 2011. For HLA typing, Blood was collected in heparin containing tube and the laboratory tests were performed by the microlymphocytotoxicity technique according to manufacturer’s instructions.Out of 19 HLA-A and 37HLA-B antigens tested, a total of 19/19 and 36/37 antigens were detectedrespectively in this study. The most frequent antigens of HLA-A and HLA-B detected were A11 (25.4%), A24 (16.6%), B75 (18.1%) and B35 (11.3%). The least antigen frequency detected for HLA-A locus were A69 (0.09%), A26 (0.28%), A34 (0.28%), while for HLA-B locus were B81 (0.09%) and B56 (0.09%). Among the HLA-A and HLA-B antigens, some alleles were found to be homozygote such as A11 (4.0%), A2 (2.7%), A24 (2.1%) andB75 (2.4%), B35 (1.8%), and B44 (1.4%) respectively. The most frequent haplotype in the study populationwereA11: B75 (4.9%). The most frequent antigens of HLA-A and HLA-B detected were A11 (25.4%), B75 (18.1%) respectively. The distribution of HLA haplotypes among the study population indicates that it has the influence of Oriental and Asian populations. Thus, this study will be helpful to provide valuable information for population genetics and HLA disease association analysis.Bangladesh Med Res Counc Bull 2018; 44(1):01-08

Molecular definition of the transplantation antigens.

In the first half of the 20th century, the major histocompatibility complex (MHC) of the laboratory mouse, the H-2 complex, was defined by a combination of serology and genetics. In the second half of the 20th century, its human counterpart, the human leukocyte antigen (HLA) complex was similarly defined and shown to mediate rejection of allogeneic kidney grafts. The clinical relevance of the transplantation antigens created the field of transplant immunology, which aimed to reduce graft rejection by HLA matching of transplant donors and recipients, and to use immunosuppressive drugs to prevent and treat rejection. Because tissue transplantation is not a natural phenomenon, the relevance of the MHC for immunology and immune defense against microbial pathogens was frequently questioned. In the 1970s, the general observation that cytotoxic T-cell responses to viral infection required recognition of both a viral antigen and a transplantation antigen argued for the immunological importance of the MHC. Proving this point was not achieved until close to the end of the 20th century. This required detailed biochemical and structural analysis of the transplantation antigens, the viral antigens, and the T-cell receptors that recognized them. This century of research culminated in 1996 with the three-dimensional crystallographic structure of the complex of these three components. In this complex is MAC, the very first HLA antigen to be detected and now more formally known as HLA-A*02:01.

Does human leukocyte antigens sensitization matter for xenotransplantation?

The major histocompatibility complex class I and class II human leukocyte antigens (HLA) play a central role in adaptive immunity but are also the dominant polymorphic proteins targeted in allograft rejection. Sensitized patients with high levels of panel-reactive anti-HLA antibody (PRA) are at risk of early allograft injury, rejection, reduced allograft survival and often experience prolonged waiting times prior to transplantation. Xenotransplantation, using genetically modified porcine organs, offers a unique source of donor organs for these highly sensitized patients if the anti-HLA antibody, which places the allograft at risk, does not also enhance anti-pig antibody reactivity responsible for xenograft rejection. Recent improvements in xenotransplantation efficacy have occurred due to improved immune suppression, identification of additional xenogeneic glycans, and continued improvements in donor pig genetic modification. Genetically engineered pig cells, devoid of the known xenogeneic glycans, minimize human antibody reactivity in 90% of human serum samples. For waitlisted patients, early comparisons of patient PRA and anti-pig antibody reactivity found no correlation suggesting that patients with high PRA levels were not at increased risk of xenograft rejection. Subsequent studies have found that some, but not all, highly sensitized patients express anti-HLA class I antibody which cross-reacts with swine leukocyte antigen (SLA) class I proteins. Recent detailed antigen-specific analysis suggests that porcine-specific anti-SLA antibody from sensitized patients binds cross-reactive groups present in a limited subset of HLA antigens. This suggests that using modern genetic methods, a program to eliminate specific SLA alleles through donor genetic engineering or stringent donor selection is possible to minimize recipient antibody reactivity even for highly sensitized individuals.

Study on association of human leukocyte antigen-DRB1 alleles amongst Bangladeshi patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic, systemic and autoimmune disease affecting 0.5-1% of the world population. Genetic and environmental factors are already established as being involved in the development of RA. Different human leukocyte antigen (HLA)-DRB1 alleles have major pathogenic effects to the development of RA. To determine the HLA-DRB1 allelic frequency of RA in one Bangladeshi tertiary care center. This case-control study was conducted at the Microbiology and Rheumatology Department of Bangabandhu Sheikh Mujib Medical University (BSMMU). Fifty-two patients diagnosed as having RA and 52 healthy controls were enrolled. Buccal swabs were collected from all subjects and HLA-DRB1 typing was carried out with polymerase chain reaction with sequence-specific primers (PCR-SSP) of low resolution. Blood was also collected for auto-antibodies (rheumatoid factor [RF] and anti-cyclic citrullinated peptide [anti-CCP]) detection from all subjects. RF was detected by nephelometry and anti-CCP was detected by using the enzyme-linked immunosorbent assay method. Statistical associations of HLA antigen between the groups were determined by chi-square test. In RA patients DR*04 and DR*10 were found at the DRB1 locus at higher frequencies (20.5%, P=0.0035 and 18.3%, P=0.0045, respectively). However, the frequency of DR*15 was significantly lower (P=0.005) in RA cases (18.3%) than the control group (35.6%). The frequencies of autoantibodies (anti-CCP and RF) were compared between approximate shared epitope (SE) positive and SE negative patients, and no significant association was found. In this study DRB1*04 and DRB1*10 alleles were significantly associated with RA patients while DRB1*15 was found more in the control group.

Binding stability of peptides on major histocompatibility complex class I proteins: role of entropy and dynamics

Prediction of peptide binding on specific human leukocyte antigens (HLA) has long been studied with successful results. We herein describe the effects of entropy and dynamics by investigating the binding stabilities of 10 nanopeptides on various HLA Class I alleles using a theoretical model based on molecular dynamics simulations. The fluctuational entropies of the peptides are estimated over a temperature range of 310–460 K. The estimated entropies correlate well with experimental binding affinities of the peptides: peptides that have higher binding affinities have lower entropies compared to non-binders, which have significantly larger entropies. The computation of the entropies is based on a simple model that requires short molecular dynamics trajectories and allows for approximate but rapid determination. The paper draws attention to the long neglected dynamic aspects of peptide binding, and provides a fast computation scheme that allows for rapid scanning of large numbers of peptides on selected HLA antigens, which may be useful in defining the right peptides for personal immunotherapy.

Lym-1 Chimeric Antigen Receptor T Cells Exhibit Potent Anti-Tumor Effects against B-Cell Lymphoma.

T cells expressing chimeric antigen receptors (CARs) recognizing CD19 epitopes have produced remarkable anti-tumor effects in patients with B-cell malignancies. However, cancer cells lacking recognized epitopes can emerge, leading to relapse and death. Thus, CAR T cells targeting different epitopes on different antigens could improve immunotherapy. The Lym-1 antibody targets a conformational epitope of Human Leukocyte Antigen-antigen D Related (HLA-DR) on the surface of human B-cell lymphomas. Lym-1 CAR T cells were thus generated for evaluation of cytotoxic activity towards lymphoma cells in vitro and in vivo. Human T cells from healthy donors were transduced to express a Lym-1 CAR, and assessed for epitope-driven function in culture and towards Raji xenografts in NOD-scidIL2Rgammanull (NSG) mice. Lym-1 CAR T cells exhibited epitope-driven activation and lytic function against human B-cell lymphoma cell lines in culture and mediated complete regression of Raji/Luciferase-Green fluorescent protein (Raji/Luc-GFP) in NSG mice with similar or better reactivity than CD19 CAR T cells. Lym-1 CAR transduction of T cells is a promising immunotherapy for patients with Lym-1 epitope positive B-cell malignancies.

The impact of human leukocyte antigen mismatching on graft survival and mortality in adult renal transplantation: A protocol for a systematic review and meta-analysis.

Background:Human leukocyte antigen (HLA) was important biological barrier to a successful transplantation. Quantitative evaluations of the effect of HLA mismatching on heart, liver, umbilical cord blood, and hematopoietic stem cell transplantation, have previously been reported. In new era of immunosuppression, the reported magnitude effect of HLA mismatching on survival outcomes of kidney transplantation was controversial. In addition, the current kidney allocation guideline recommendations in different countries were inconsistent in term of HLA mismatching. We undertake this study to conduct a systematic review and meta-analysis to assess the magnitude effect of HLA mismatching in adult kidney transplantation, with a particular focus on graft survival and mortality.Methods:The present systematic review and meta-analysis protocol was conducted following the Meta-analysis of Observational Studies in Epidemiology protocol (MOOSE-P) and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis protocol (PRISMA-P). PubMed, EMBASE, Cochrane library Database will be searched without language restriction. Studies fulfill the following criteria will be eligible: included study cohorts comprising adult recipients; reported the association between HLA mismatching (per mismatches or HLA-A, -B, -DR mismatches) and posttransplant survival outcomes; provided effect estimates of hazard ratios (HRs) with 95% confidence interval (CIs). The incidence of measured outcomes was defined according to the European Renal Best Practice Transplantation Guidelines and Kidney Disease: Improving Global Outcomes Guidelines.Results:This study will quantitatively assess the association of HLA per mismatches, DR-antigen mismatches, A-antigen mismatches, and B-antigen mismatches with survival outcomes of overall graft failure, death-censored graft failure, all-cause mortality, and mortality with a functioning graft.Conclusion:This study will determine the issues on what extent HLA compatibility influenced recipient and graft survival and which HLA antigen plays a more important role in kidney transplantation.Systematic review registration:PROSPERO CRD42017071894.

Development and validation of immune dysfunction score to predict 28-day mortality of sepsis patients.

BackgroundSepsis-induced immune dysfunction ranging from cytokines storm to immunoparalysis impacts outcomes. Monitoring immune dysfunction enables better risk stratification and mortality prediction and is mandatory before widely application of immunoadjuvant therapies. We aimed to develop and validate a scoring system according to patients’ immune dysfunction status for 28-day mortality prediction.MethodsA prospective observational study from a cohort of adult sepsis patients admitted to ICU between August 2013 and June 2016 at Kaohsiung Chang Gung Memorial Hospital in Taiwan. We evaluated immune dysfunction status through measurement of baseline plasma Cytokine levels, Monocyte human leukocyte-DR expression by flow cytometry, and stimulated immune response using post LPS stimulated cytokine elevation ratio. An immune dysfunction score was created for 28-day mortality prediction and was validated.ResultsA total of 151 patients were enrolled. Data of the first consecutive 106 septic patients comprised the training cohort, and of other 45 patients comprised the validation cohort. Among the 106 patients, 21 died and 85 were still alive on day 28 after ICU admission. (mortality rate, 19.8%). Independent predictive factors revealed via multivariate logistic regression analysis included segmented neutrophil-to-monocyte ratio, granulocyte-colony stimulating factor, interleukin-10, and monocyte human leukocyte antigen-antigen D–related levels, all of which were selected to construct the score, which predicted 28-day mortality with area under the curve of 0.853 and 0.789 in the training and validation cohorts, respectively.ConclusionsThe immune dysfunction scoring system developed here included plasma granulocyte-colony stimulating factor level, interleukin-10 level, serum segmented neutrophil-to-monocyte ratio, and monocyte human leukocyte antigen-antigen D–related expression appears valid and reproducible for predicting 28-day mortality.