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This paper describes for the first time the differential immune response to virulent Newcastle disease virus (NDV) in birds differing in cell-mediated immunity, as measured by response to phytohaemagglutinin-P. To explore potential host–pathogen interactions, peripheral blood mononuclear cells (PBMC) were collected from 40 extreme responder birds (20 birds each from high and low cell-mediated immunity lines). PBMC cultures were stimulated by virulent NDV and temporal expression profiles of interferon-gamma (IFN-γ), and inducible nitric oxide synthase (iNOS) mRNA was evaluated by semiquantitative reverse transcription polymerase chain reaction (PCR). To further explore the correlation of iNOS mRNA expression and nitric oxide (NO) production, we assayed the culture supernatants for NO. NO production, as well as iNOS and IFN-γ mRNA expression, was significantly ( P < 0.05) higher in the line with higher cell-mediated immunity. In our study, a significant ( P < 0.05) difference was observed between the lines for IFN-γ promoter polymorphism for the TspEI site. The high cell-mediated immunity line mostly revealed the genotype (GG) with a 168-bp fragment. On the other hand, this genotype was not predominant in the low cell-mediated immunity line. Later, quantitative real-time PCR demonstrated higher ( P < 0.01) IFN-γ mRNA transcription in the genotype GG in response to NDV. This difference in promoter region may be responsible for differential IFN-γ mRNA transcription in chicken lines. Furthermore, birds of high cell-mediated immunity line showed better adaptive immunity to booster NDV vaccination as revealed by an enhanced antibody titre. Thus, this study provides baseline data on the effect of phytohaemagglutinin-P response-based selection on immune responses to virulent NDV and the data could be of immense importance to poultry geneticist and immunologist attempting to breed poultry for disease resistance. [ABSTRACT FROM AUTHOR]

Interleukin 18 (IL-18) has been identified as a potent upstream cytokine required for upregulation of IFN-γ secretion that plays a crucial role in polarization of Th1 type of immune response. Considering the potential applications of the cytokine in immunomodulation, it has been characterized in many livestock species including cattle, equines, canines, felines and porcines. In this paper we report the isolation, cloning sequencing and expression of caprine precursor IL-18. Full-length caprine IL-18 cDNA was isolated from mitogen-stimulated adherent peripheral blood mononuclear cells using reverse transcription polymerase chain reaction (RT-PCR). The cDNA contained an open reading frame of 579 bp encoding a putative polypeptide of 192 amino acids. Deduced amino acid sequence of caprine IL-18 showed varying amino acid identity with the published sequences of other domestic ruminant species ranging from 94.3% to 96.9%, while it shared over 78% aa identity with other domestic animals. Pairwise multiple aligned sequences showed a deletion of Glu31in caprine IL-18 unlike in other species. Recombinant caprine IL-18 was produced in Escherichia coli, which cross-reacted with two antiporcine IL-18 monoclonal antibodies. [ABSTRACT FROM AUTHOR]

The development of donor‐specific antibodies (DSAs) is a major complication in transplantation, which is associated with inferior graft survival, impaired quality of life, and increased healthcare costs. DSA develop upon recognition of nonself HLA by the recipient's immune system. HLA molecules contain epitopes, which are the surface regions of HLA molecules recognized by antibodies. HLAMatchmaker is an algorithm for assessing donor:recipient HLA compatibility at the level of structurally defined HLA targets called eplets. The consideration of eplets, rather than the whole HLA molecule, could offer some advantages when classifying the immune risk associated with particular donor:recipient pairs. Assessing compatibility at the level of HLA eplets could decrease misclassification of post‐transplant immune risk by improving specificity, when antibodies are confirmed to be directed against donor eplets missing from the recipient's repertoire of eplets. Consideration of eplets may also increase the sensitivity of immune risk assessment, when identifying mismatched eplets that could give rise to new, not previously detected, donor‐specific antibodies post‐transplant. Eplet matching can serve as a rational strategy for immune risk mitigation. Herein, we review the evolution of HLA (in) compatibility assessment for organ allocation. We outline challenges in the implementation of eplet‐based donor:recipient matching, including unavailability of allele‐level donor genotypes for 11 HLA loci at the time of organ allocation and difficulty in assessing the hierarchy of immune risk associated with particular HLA eplet mismatches. Opportunities to address some of the current shortcomings of donor genotyping and HLAMatchmaker are also discussed. While there is a demonstrated benefit in the application of HLAMatchmaker for donor: recipient HLA (in)compatibility assessment, evolving long‐read genotyping methods, compilation of large data sets with allele‐level genotypes, and standardization of methods to verify eplets as determinants of immune‐mediated injuries are required before HLA eplet matching is implemented in organ allocation to improve upon transplant outcomes. [ABSTRACT FROM AUTHOR]

HLA donor‐specific antibodies developed de novo after transplant remain a major cause of chronic allograft dysfunction. Our study main purpose was to determine whether HLA MM, assessed traditionally and by HLA total and AbVer eplet mismatch load (EptMM and EpvMM) assessed with HLAMatchMaker, had impact on dnDSA development after living donor kidney transplantation (LDKT). We retrospectively analysed a cohort of 96 LDKT between 2008 and 2017 performed in Hospital Santo António. Seven patients developed dnDSA‐II and EpvMM and EptMM were greater in dnDSA‐II group compared to the no dnDSA‐II (18.0 ± 8.7 versus 9.9 ± 7.9, p =.041 and 41.3 ± 18.9 versus 23.1 ± 16.7, p =.018), which is not observed for AgMM (2.29 versus 1.56; p =.09). In a multivariate analysis, we found that preformed DSA (HR = 7.983; p =.023), living unrelated donors (HR = 8.052; p =.024) and retransplantation (HR = 14.393; p =.009) were predictors for dnDSA‐II (AUC = 0.801; 0.622–0.981). HLA‐II EpvMM (HR = 1.105; p =.028; AUC = 0.856) showed to be a superior predictor of dnDSA‐II, when compared to AgMM (HR = 1.740; p =.113; AUC = 0.783), when adjusted for these clinical variables. Graft survival was significantly lower within dnDSA‐II patient group (36% versus 88%, p <.001). HLA molecular mismatch analysis is extremely important to minimize risk for HLA‐II dnDSA development improving outcome and increasing chance of retransplant lowering allosensitization. [ABSTRACT FROM AUTHOR]

We analysed data from 80 patients who tested positive for SARS‐CoV‐2 RNA who had previously been HLA typed to support transplantation. Data were combined from two adjacent centres in Manchester and Leeds to achieve a sufficient number for early analysis. HLA frequencies observed were compared against two control populations: first, against published frequencies in a UK deceased donor population (n = 10,000) representing the target population of the virus, and second, using a cohort of individuals from the combined transplant waiting lists of both centres (n = 308), representing a comparator group of unaffected individuals of the same demographic. We report a significant HLA association with HLA‐ DQB1*06 (53% vs. 36%; p <.012; OR 1.96; 95% CI 1.94–3.22) and infection. A bias towards an increased representation of HLA‐A*26, HLA‐DRB1*15, HLA‐DRB1*10 and DRB1*11 was also noted but these were either only significant using the UK donor controls, or did not remain significant after correction for multiple tests. Likewise, HLA‐A*02, HLA‐B*44 and HLA‐C*05 may exert a protective effect, but these associations did not remain significant after correction for multiple tests. This is relevant information for the clinical management of patients in the setting of the current SARS‐CoV‐2 pandemic and potentially in risk‐assessing staff interactions with infected patients. [ABSTRACT FROM AUTHOR]

Susceptibility to viral infection, development of immunity, response to treatment and patient clinical outcomes are all under the control of heritable factors in the host. In the context of the current SARS‐Cov‐2 pandemic, this review considers existing immunogenetic knowledge of virus‐immune system interactions. A major focus is to highlight areas in which work is required in order to improve understanding of antiviral immune responses and to move towards improved patient management. [ABSTRACT FROM AUTHOR]

The detection and semiquantitative measurement of circulating human leucocyte antigen (HLA)‐specific antibodies is essential for the management of patients before and after transplantation. In addition, the pretransplant cross‐match to assess the reactivity of recipient HLA antibody against donor lymphocytes has long been the gold standard to prevent hyperacute rejection. Whilst both of these tests assume that recipient HLA‐specific antibody is the only variable in the assessment of transplant risk, this is not the case. Transplant immunologists recognize that some HLA antigens are expressed at levels a magnitude lower than others (e.g., HLA‐C, HLA‐DQ), but within loci, and between different cell types there are many factors that influence HLA expression in both resting and activated cells. HLA is not usually expressed without the specific promoter proteins NLRC5, for HLA class I, and CIITA, for class II. The quantity of HLA protein production is then affected by factors including promoter region polymorphisms, alternative exon splice sites, methylation and microRNA‐directed degradation. Different loci are influenced by multiple combinations of these control mechanisms making prediction of HLA regulation difficult, but an ability to measure the cellular expression of each HLA antigen, in conjunction with knowledge of circulating HLA‐specific antibody, would lead to a more informed algorithm to assess transplant risk. [ABSTRACT FROM AUTHOR]

Despite the apparent simplicity of the body organization of echinoderms, their immune system is competent to perform a complex innate immune response, which is far from being well understood. The echinoderms represent the most advanced invertebrates that form a bridge with the primitive chordates. In fact, they possess numerous receptors and effectors that are used to obtain a fast immune response. After an infection, the humoral and cellular immune response determines a network in which the main protagonists are membrane and endosomal receptors. The recognition of nonself molecules by specific membrane receptors triggers the immune response, stimulating consecutive intracellular events. We have previously shown how the polyinosinic–polycytidylic acid (polyI:C) that mimics a viral infection is able to induce an immune response in the sea urchin Paracentrotus lividus immune cells. It activates a specific membrane receptor belonging to the Toll‐like receptor (TLR) family. Here, we show the activated expression pattern of some genes involved in the downstream cascade of TLR signalling pathway, such as Pl‐Tbk and Pl‐Irf, whose partial sequence was isolated from P. lividus immune cells. Their mRNA expression increases consequentially to the polyI:C stimulation and in a temporal way. In addition, we analysed the expression of Pl‐NF‐kB and we found that its upregulation was time‐dependent, preceding Pl‐Tbk and Pl‐Irf increase. Protein analysis showed that also some cytokine (TNF‐α and IL‐1α) expression increased after polyI:C insult. Therefore, the purpose of this study was to discover the molecular mechanisms of the innate defence strategies, similarly to vertebrates, implemented by the sea urchins in order to cope with viral infection challenge. [ABSTRACT FROM AUTHOR]

Loss of heterozygosity is considered to be the most common type of tumour‐specific somatic mutation of the human leucocyte antigens (HLA) genes in patients with haematological malignancies. Nevertheless, subtle DNA sequence changes, namely short insertions/deletions, may also abolish the expression of HLA molecules and interfere with routine HLA typing. Two male patients with acute myelogenous leukaemia (AML) were indicated for the search of a suitable donor for allogeneic haematopoietic stem cell transplantation (aHSCT). The patients and their relatives were initially HLA typed by serological and DNA techniques at a low‐resolution level. The HLA high‐resolution (HR) type was obtained by means of sequencing‐based typing (SBT). In both cases, anomalous frameshifts in the sequence were observed in the HLA‐B gene, namely in exon 3 (Case 1, heterozygous deletion of two bases) and exon 4 (Case 2, heterozygous insertion of two bases). In the second case, the insertion variant was associated with a loss of HLA‐B8 expression. To reveal whether these sequence patterns may be caused by somatic mutations in the malignant cells, blood sample in remission (Case 1) and buccal swab sample (Case 2) were collected from the patients. In an important manner, the SBT in these germline samples revealed common HLA‐B*07:02,*15:01 (Case 1) and HLA‐B*08:01,*35:02 (Case 2) types with no evidence for the sequence alteration observed in the initial samples. In conclusion, the insertion/deletion sequence variants of the HLA‐B gene in two patients were limited to the initial blood samples with a substantial proportion of AML cells and thus may be attributed to the somatic mutation in the malignant cells. HLA somatic mutations should be taken into account in patients with haematological malignancies to prevent HLA mistyping and inappropriate selection of an aHSCT donor. [ABSTRACT FROM AUTHOR]

The major histocompatibility complex ( MHC) is located in chromosome 6p21 and contains crucial regulators of immune response, including human leucocyte antigen ( HLA) genes, alongside other genes with nonimmunological roles. More recently, a repertoire of noncoding RNA genes, including expressed pseudogenes, has also been identified. The MHC is the most gene dense and most polymorphic part of the human genome. The region exhibits haplotype-specific linkage disequilibrium patterns, contains the strongest cis- and trans- eQTLs/me QTLs in the genome and is known as a hot spot for disease associations. Another layer of complexity is provided to the region by the extreme structural variation and copy number variations. While the HLA-B gene has the highest number of alleles, the HLA- DR/ DQ subregion is structurally most variable and shows the highest number of disease associations. Reliance on a single reference sequence has complicated the design, execution and analysis of GWAS for the MHC region and not infrequently, the MHC region has even been excluded from the analysis of GWAS data. Here, we contrast features of the MHC region with the rest of the genome and highlight its complexities, including its functional polymorphisms beyond those determined by single nucleotide polymorphisms or single amino acid residues. One of the several issues with customary GWAS analysis is that it does not address this additional layer of polymorphisms unique to the MHC region. We highlight alternative approaches that may assist with the analysis of GWAS data from the MHC region and unravel associations with all functional polymorphisms beyond single SNPs. We suggest that despite already showing the highest number of disease associations, the true extent of the involvement of the MHC region in disease genetics may not have been uncovered. [ABSTRACT FROM AUTHOR]

Haematopoietic stem cell transplantation ( HSCT) remains the only cure for many haematological neoplasms; however, the mortality rate remains high, at around 30-80%. Complications after HSCT include relapse, graft-versus-host disease, graft rejection and infection. High-resolution HLA matching has improved survival in HSCT over recent years; however, GVHD still remains a serious complication. Single nucleotide polymorphisms ( SNPS) within genes that are involved with an individual's capability to mount an immune response to infectious pathogens, residual leukaemia, alloantigens or genes involved in drug metabolism have been studied for their association with HSCT outcome. Indeed, over the last 15 years, several groups, including ourselves, have demonstrated that non- HLA gene polymorphisms can be predictive of HSCT outcome. Can genetic characteristics of the patient and donor be used in the future to tailor HSCT protocols and determine GVHD prophylaxis? This review summarizes some of the recent SNP association studies in HSCT and highlights some of the disparities therein, discussing the integral problems of performing genetic association studies on diseases with complex outcomes using heterogeneous cohorts. The review will comment on recent genomewide association studies ( GWAS) and discuss their relevance in this field, and it will also comment on recent meta-analysis combining GWAS studies with other studies such as gene expression micro array data in the field of autoimmune disease and solid organ transplantation. It will mention possible novel candidate gene polymorphisms, for example SNPS in micro RNAs. In addition, it will discuss some of the inherent problems associated with gene association studies including the GRIPs (genetic risk prediction studies) recommendations. In summary, this review will assess the usefulness of non- HLA genomic studies in HSCT with regard to predicting outcome and modifying therapy. [ABSTRACT FROM AUTHOR]