An Extremes of outcome strategy provides evidence that multiple sclerosis severity is determined by alleles at the <i>HLA-DRB1</i> locus

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system unsurpassed for variability in disease outcome. A cohort of sporadic MS cases (n=63), taken from opposite extremes of the distribution of long-term outcome, was used to determine the role of the HLA-DRB1 locus on MS disease severity. Genotyping sets of benign and malignant MS patients showed that HLA-DRB1*01 was significantly underrepresented in malignant compared with benign cases. This allele appears to attenuate the progressive disability that characterizes MS in the long term. The observation was doubly replicated in (i) Sardinian benign and malignant patients and (ii) a cohort of affected sibling pairs discordant for HLA-DRB1*01. Among the latter, mean disability progression indices were significantly lower in those carrying the HLA-DRB1*01 allele compared with their disease-concordant siblings who did not. The findings were additionally supported by similar transmission distortion of HLA-DRB1*04 subtypes closely related to HLA-DRB1*01. The protective effect of HLA-DRB1*01 in sibling pairs may result from a specific epistatic interaction with the susceptibility allele HLA-DRB1*1501. A high-density (&gt;700) SNP examination of the MHC region in the benign and malignant patients could not identify variants differing significantly between the two groups, suggesting that HLA-DRB1 may itself be the disease-modifying locus. We conclude that HLA-DRB1*01, previously implicated in disease resistance, acts as an independent modifier of disease progression. These results closely link susceptibility to long-term outcome in MS, suggesting that shared quantitative MHC-based mechanisms are common to both, emphasizing the central role of this region in pathogenesis

African horse sickness virus NS4 protein is an important virulence factor and interferes with JAK-STAT signaling during viral infection

African horse sickness virus (AHSV) non-structural protein NS4 is a nucleocytoplasmic protein that is expressed in the heart, lung, and spleen of infected horses, binds dsDNA, and colocalizes with promyelocytic leukemia nuclear bodies (PML-NBs). The aim of this study was to investigate the role of AHSV NS4 in viral replication, virulence and the host immune response. Using a reverse genetics-derived virulent strain of AHSV-5 and NS4 deletion mutants, we showed that knockdown of NS4 expression has no impact in cell culture, but results in virus attenuation in infected horses. RNA sequencing (RNA-seq) was used to investigate the transcriptional response in these horses, to see how the lack of NS4 mediates the transition of the virus from virulent to attenuated. The presence of NS4 was shown to result in a 24 hour (h) delay in the transcriptional activation of several immune system processes compared to when the protein was absent. Included in these processes were the RIG-I-like, Toll-like receptor, and JAK-STAT signaling pathways, which are key pathways involved in innate immunity and the antiviral response. Thus, it was shown that AHSV NS4 suppresses the host innate immune transcriptional response in the early stages of the infection cycle. We investigated whether AHSV NS4 affects the innate immune response by impacting the JAK-STAT signaling pathway specifically. Using confocal laser scanning microscopy (CLSM) we showed that AHSV NS4 disrupts JAK-STAT signaling by interfering with the phosphorylation and/or translocation of STAT1 and pSTAT1 into the nucleus. Overall, these results showed that AHSV NS4 is a key virulence factor in horses and allows AHSV to overcome host antiviral responses in order to promote viral replication and spread.SUPPLEMENTARY MATERIAL: Supplementary table 1: Full list of differentially expressed genes in the transcriptome analysis. The genes were sorted according to log2Fold change values and then grouped according to up- or down-regulated genes. Days 1, 2 and 4 are presented for the horse inoculated with rAHSV-5 (NS4) and days 1 and 2 for the horses inoculated with rAHSV-5minNS4 (minNS4). The log2FC is indicated in bold for genes differentially expressed on the same day in both NS4 and minNS4. aRanks of up- or down-regulated genes in each comparison. *Involved in innate immunity according to InnateDB.Supplementary table 2: Full list of KEGG pathways enriched by the differentially expressed genes in the transcriptome analysis. The data is displayed per day and includes the up- and down- regulated genes enriching each pathway. Pathways were sorted based on corrected P-value. Days 1, 2 and 4 are presented for the horse inoculated with rAHSV-5 (NS4) and days 1 and 2 for the horses inoculated with rAHSV-5minNS4 (minNS4).Supplementary Figure 1: Images obtained from post-mortem examination of horses inoculated with rAHSV-5. Classical lesions of disease such as frothing from the nostrils (a), interstitial and subpleural lung edema (b, e), alveolar edema (c, f) and hydropericardium (d, g) were observed.Deltamune (Pty) Ltd, the University of Pretoria Institutional Research Themes, the Poliomyelitis Research Foundation, South Africa and the Genomics Research Institute, University of Pretoria. Postgraduate support was received from the Poliomyelitis Research Foundation, South Africa, the National Research Foundation, South Africa and the University of Pretoria, South Africa.http://www.elsevier.com/locate/virusreshj2022BiochemistryGeneticsMicrobiology and Plant Patholog

BSHI/BTS guidance on crossmatching before deceased donor kidney transplantation.

All UK H&I laboratories and transplant units operate under a single national kidney offering policy, but there have been variations in approach regarding when to undertake the pre-transplant crossmatch test. In order to minimize cold ischaemia times for deceased donor kidney transplantation we sought to find ways to be able to report a crossmatch result as early as possible in the donation process. A panel of experts in transplant surgery, nephrology, specialist nursing in organ donation and H&I (all relevant UK laboratories represented) assessed evidence and opinion concerning five factors that relate to the effectiveness of the crossmatch process, as follows: when the result should be ready for reporting; what level of donor HLA typing is needed; crossmatch sample type and availability; fairness and equity; risks and patient safety. Guidelines aimed at improving practice based on these issues are presented, and we expect that following these will allow H&I laboratories to contribute to reducing CIT in deceased donor kidney transplantation

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

The PCR-SSP Manager computer program: A tool for maintaining sequence alignments and automatically updating the specificities of PCR-SSP primers and primer mixes

An emerging problem of molecular typing methods such as PCR amplification using sequence-specific primers (PCR-SSP) is that they frequently require updating as new alleles are constantly being described which potentially affect the specificity of every PCR-SSP reaction. PCR-SSP uses pairs of primers to detect cis-linked polymorphisms and thus each new allele described must be compared to each individual primer pair. Furthermore, sequence homology between the various loci for class I and class Il means that, for example, new HLA-A sequences have to be compared with HLA-B and HLA-C primer mixes to rule out cross-locus amplification. We have developed a computer program known as SSP Manager which is capable of aligning HLA class I and class TI sequences obtained from Internet-accessible databases such as GenBank. The program then updates all individual primer specificities held in its database before updating the specificities of all primer mixes. Sets of primer mixes can then be combined from the primer mix directory to create PCR-SSP typing trays which are subsequently analysed by the program. A report is generated which stipulates whether all known sequences are amplified and the reason for apparent failure to test for individual alleles, e.g. a lack of relevant sequence information. SSP Manager has the flexibility to cope with unusual sequences (deletions and insertions), primers with internal mismatches and primers with a deliberate mismatch. The program also has many tools for developing new primer mixes, such as the facility to search for novel reactions using Boolean operators. The organisation and operational use of the SSP Manager program is described and its uses are illustrated with an updated allele list for our previously described Phototyping PCR-SSP class I and class TI typing set. The SSP Manager is available on request from the authors