Metabolic dysregulation induces impaired lymphocyte memory formation during severe SARS-CoV-2 infection

Cellular metabolic dysregulation is a consequence of COVID-19 infection that is a key determinant of disease severity. To understand the mechanisms underlying these cellular changes, we performed high-dimensional immune cell profiling of PBMCs from COVID-19-infected patients, in combination with single cell transcriptomic analysis of COVID-19 BALFs. Hypoxia, a hallmark of COVID-19 ARDS, was found to elicit a global metabolic reprogramming in effector lymphocytes. In response to oxygen and nutrient-deprived microenvironments, these cells shift from aerobic respiration to increase their dependence on anaerobic processes including glycolysis, mitophagy, and glutaminolysis to fulfill their bioenergetic demands. We also demonstrate metabolic dysregulation of ciliated lung epithelial cells is linked to significant increase of proinflammatory cytokine secretion and upregulation of HLA class 1 machinery. Augmented HLA class-1 antigen stimulation by epithelial cells leads to cellular exhaustion of metabolically dysregulated CD8 and NK cells, impairing their memory cell differentiation. Unsupervised clustering techniques revealed multiple distinct, differentially abundant CD8 and NK memory cell states that are marked by high glycolytic flux, mitochondrial dysfunction, and cellular exhaustion, further highlighting the connection between disrupted metabolism and impaired memory cell function in COVID-19. Our findings provide novel insight on how SARS-CoV-2 infection affects host immunometabolism and anti-viral response during COVID-19.

Human Leukocyte Antigen-C and Haplotypes: Associations with Resistance and Susceptibility to HIV-1 Infection among Serodiscordant Couples in Nigeria

ABSTRACTINTRODUCTIONThe Human Leucocyte Antigen (HLA) class-1 is known to play a significant role in mediating resistance or susceptibility to HIV infection in the clinical course of AIDS. Recent studies have identified HLA-C as a key molecule that affects HIV disease progression. However, the role of HLA class 1 in heterosexual HIV-1 susceptibility or resistance in serodiscordant couples is not known in Nigeria. Therefore, this study evaluated the association between HLA-C susceptibility and resistance in HIV-1 transmission amongst heterosexual serodiscordant couples in Nigeria.METHODSA total of 271 serodiscordant, concordant HIV positive and negative couples who gave informed consent were enrolled into this study. Extracted genomic DNA was sequenced for high resolution HLA-C class 1 genotypes using allele-specific primers (on exons 2 and 3) for HLA-C sequencing and typing.RESULTSThe highest frequency distribution of high-resolution HLA-C alleles observed in the HIV positive subjects were: HLA-C*040101 178 (35.0%) followed by C*0701 124 (24.9%) compared with HIV negative subjects: C*040101 108(39.0%) followed by C*0701 64(24.7%). Alleles C*070201 (OR = 4.19, P<0.05) and C*0804 (OR = 3, P<0.045) were found to be independently associated with HIV-1 susceptibility in the cohort of serodiscordant couples. HLA-C*0802 (OR=0.5. P<0.005) and C*0304 (OR=0.34. P<0.002) were significantly associated with HIV-1 resistance to HIV-1 infection among the cohort.CONCLUSIONThe result has contributed to the importance of how host HLA-C genetic factors can influence HIV-1 disease susceptibility (HLA-C*070201; C*0804) and resistance (HLA-C*0802; C*0304) in serodiscordant couples. This information may contribute to the development of future effective HIV vaccine in Nigeria.

Predicting toxicity and response to pembrolizumab through germline genomic HLA class 1 analysis

Background Human leukocyte antigen class 1 (HLA-1)-dependent immune activity is linked to autoimmune diseases. HLA-1-dependent CD8+ T cells are required for immune checkpoint blockade (ICB) anti-tumor activity. It is unknown if HLA-1 genotype is predictive of toxicity to ICB. Methods Patients with advanced solid tumors stratified into five cohorts received single agent pembrolizumab (anti-PD-1) 200 mg IV every 3 weeks in an investigator-initiated phase II trial (INSPIRE study, NCT02644369). Germline whole exome sequencing (WES) of peripheral blood mononuclear cells was performed using the Illumina HiSeq2500 platform. HLA-1 haplotypes were predicted from WES using HLAminer and HLAVBSeq. Heterozygosity of HLA-A, -B and -C, individual HLA-1 alleles and HLA haplotype dimorphism at positions -21 M and -21 T of the HLA-A and -B leader sequence were analyzed as predictors of: toxicity defined as ≥ Grade 2 immune-related adverse events; and clinical benefit (CB) defined as complete or partial response, or stable disease for ≥ 6 cycles of pembrolizumab. Statistical significance tests were two-sided. Results In the overall cohort of 101 patients, the frequency of toxicity and CB from pembrolizumab was 22.8% and 25.7%, respectively. There was no association between any of the HLA-1 loci or alleles with toxicity. HLA-C heterozygosity had an association with decreased CB relative to HLA-C homozygosity when controlling for cohort (OR = 0.28, 95% CI 0.09–0.91, p = .04). HLA-A and -B haplotype -21 M/T dimorphism and heterozygosity of HLA-A, -B and -C were not predictive of outcomes. Conclusions HLA-C heterozygosity may predict decreased response to pembrolizumab. Prospective validation is required.

Post-Transfusion Purpura Mimicking Idiopathic Thrombocytopenic Purpura: A Case Report

The main clinical distinction between post-transfusion purpura (PTP) and idiopathic thrombocytopenic purpura (ITP) is the sudden development of severe thrombocytopenia in the days after transfusion. Herein, we report the case of a 53-year-old Caucasian woman who developed multiple myeloma (MM) after peripheral blood-stem-cell transplant (PBSCT), along with severe thrombocytopenia (with a nadir of 1 × 109/L); she also experienced severe adverse events after each platelet transfusion, including the first one. These reactions were absent with any other transfused blood products. The results of an human leukocyte antigen (HLA) class-1 panel reactive antibody assay were 0%, and the results of a platelet-antibody screening assay were positive for HLA class-1 antibodies and glycoprotein (Gp)IIb/IIIa antibodies. Her platelet count reached 42 × 109 per L on day 50, after rituximab on day 22 and daratumumab on day 29. Her clinical scenario was most consistent with the course of PTP.

COX2 and HLA immunohistochemical (IHC) staining in colorectal tumour samples from patients participating in the ASCOLT clinical trial of adjuvant aspirin therapy.

695 Background: ASCOLT is an international Phase III randomized control trial (NCT00565708) investigating the impact of adjuvant aspirin on recurrence and survival after curative resection of colorectal cancer (CRC). Retrospective data suggest that COX2 and HLA Class 1 antigen expression may predict for aspirin benefit (Reimers MS, JAMA internal medicine, 2014;174(5):732-739; and Chan AT, JAMA, 2009;302(6):649-658.) Translational studies aim to confirm putative biomarkers of aspirin sensitivity in this prospective trial. This study reports the IHC assessment of COX2 and HLA in representative samples. Methods: FFPE slides from consenting Australian patients were stained with COX2 and HLA Class 1 antibodies (Chan AT, JAMA, 2009;302(6):649-658.). Digital images were captured using Aperio software. IHC expression was scored by a pathologist (DW) blinded to sample identification. Intensity was assessed semi-quantitatively for each antibody in one area of dominant (primary) intensity and one of secondary intensity in each section. A scale was applied for staining intensity: 0=absent, 1=weak, 2=moderate and 3=strong; and for amount of tumor epithelium stained: 1= 5%-24%, 2= 25%-49%, 3=50%-74% 4= >75%. Normal epithelium, which typically has strong COX2 and HLA staining, was used as internal control. Only tumor epithelium was scored (not inflammatory cells). Results: 90 tumors were stained for both COX2 and HLA Class 1. All tumors showed diffuse staining for both markers, mostly strong, but with many tumors having regions with lesser degrees of expression (Table). Conclusions: COX2 expression was generally strong and HLA Class 1 was more likely to show regions of weak to moderate expression. No significant correlation was detected between COX2 and HLA expression levels. Further pathological analysis is underway and correlations will be made with outcome once trial data has matured in 2020. Clinical trial information: NCT00565708. [Table: see text]