Association of apolipoprotein E4 to the number of cerebral microbleeds in patients recovered from COVID-19

Background: COVID-19 has been associated with cerebral microbleeds (CMB). Previously, an association of ApoE4 with COVID-19 severity and CMBs in autopsy was found. In this study, we investigated if carrying the Apoe4 allele relates to the number of CMBs in magnetic resonance imaging (MRI) in patients recovered from COVID-19. Material(s) and Method(s): Adult patients recovered from COVID-19 and a control group without a history of COVID-19 was recruited. Exclusion criteria were major neurologic disease, developmental disability or pregnancy. The participants underwent brain MRI 6 months after infection, and a blinded neuroradiologist analyzed the findings. ApoE was genotyped using a microarray. Statistical analysis was performed using the statistical software R. A negative binomial model was chosen based on the distribution of CMBs. Result(s): Of the 216 subjects that underwent MRI, 168 consented to genetic testing, additionally 2 patients were excluded due to extensive CMBs and 1 due to diffuse axonal injury. We included 113 COVID-19 patients (49 ICU-treated, 29 ward-treated and 35 home-isolated) and 52 controls. The most prevalent comorbidities were hypertension, asthma and diabetes. CMBs was found in 47 subjects, with the number of CMBs ranging from 0 to 26. The ApoeE4 allele was carried by 37%, equally distributed among the groups. After adjustment, age (aRR = 1.06, p = 0.007) and COVID-19 (aRR = 2.59, p = 0.038) were independently associated with CMBs. The ApoE4 allele (aRR = 2.16, p = 0.07, CI = 0.94-5.10) was not significant. Conclusion(s): Age and previous COVID-19, but not possession of the ApoeE4 allele, were independently associated with the number of CMBs.

Association of genetic polymorphisms in glucocorticoid pathway with dexamethasone treatment in COVID-19 patients

Background/Objectives: Corticosteroids are widely used for the treatment of coronavirus disease (COVID)-19 caused by SARS-CoV- 2 as they attenuate the immune response with their antiinflammatory properties. Genetic polymorphisms of glucocorticoid receptor, metabolizing enzymes or transporters may affect treatment response to dexamethasone. The aim of this study was to evaluate the association of polymorphisms in glucocorticoid pathway with disease severity and duration of dexamethasone treatment in COVID-19 patients. Method(s): Our study included 107 hospitalized COVID-19 patients treated with dexamethasone. We isolated DNA from peripheral blood and genotyped all samples for polymorphisms in NR3C1 (rs6198, rs33388), CYP3A4 (rs35599367), CYP3A5 (rs776746), GSTP1 (rs1695, rs1138272), GSTM1/GSTT1 deletions and ABCB1 (1045642, rs1128503, rs2032582 Fisher's and Mann- Whitney tests were used in statistical analysis. Result(s): The median (min-max) age of the included patients was 62 (26-85) years, 69.2 % were male and 30.8 % female and they had moderate (1.9 %), severe (83 %) or critical (15.1 %) disease. NR3C1 rs6198 polymorphism was associated with more severe disease in additive genetic model (P = 0.022). NR3C1 rs6198, ABCB1 rs1045642 and ABCB1 rs1128503 polymorphisms were associated with a shorter duration of dexamethasone treatment in additive (P = 0.048, P = 0.047 and P = 0.024, respectively) and dominant genetic models (P = 0.015, P = 0.048 and P = 0.020, respectively), while carriers of the polymorphic CYP3A4 rs35599367 allele required longer treatment with dexamethasone (P = 0.033). Other polymorphisms were not associated with disease severity or dexamethasone treatment duration. Conclusion(s): Genetic variability of glucocorticoid pathway genes was associated with the duration of dexamethasone treatment of COVID-19 patients.

IRF2BP2 mutation with autoimmune enteropathy, immune deficiency, and respiratory failure

Case history: We present the case of a 31-year-old Hispanic male with history of recurrent bronchiectasis, invasive aspergillosis, and severe persistent asthma, who is now status post lung transplant for end-stage lung disease. He initially presented at 7 years of age with diarrhea, failure to thrive, and nearly absent immunoglobulin levels (IgG < 33 mg/dL, IgA < 7 mg/dL, IgM = 11 mg/dL, IgE = 4 IU/dL) necessitating IVIG treatment. Small intestinal biopsy showed villous atrophy consistent with autoimmune enteropathy. Sweat chloride was reported as indeterminate (44 me/dL). Initial WBC, platelet, and T- and NK-cell counts were within normal range, and B-cell count and percentage were borderline low. Most recently, he was found to have increased immature B-cell count (CD21low), decreased memory B-cells, and poor pneumococcal vaccine antibody response. Patient has been hospitalized numerous times with increasingly severe bronchiectasis, pneumonitis, and COVID-19 infections twice despite vaccination, leading to respiratory failure and lung transplantation. Family history is negative for immune deficiency and lung diseases. Discussion(s): Of these 3 VUSs (see the table), the one in IRF2BP2 has the most pathogenic potential due to its autosomal dominant inheritance, its location in a conserved domain (Ring), and previous case reports of pathogenic variants at the same or adjacent alleles 1-3. Baxter et al reported a de novo truncating mutation in IRF2BP2 at codon 536 (c.1606CinsTTT), which is similar to our patient's mutation. This patient was noted to have an IPEX-like presentation, with chronic diarrhea, hypogammaglobulinemia, and recurrent infections. Variant Functional Prediction Score for our variant predicts a potentially high damage effect. There are 2 other case reports of heterozygous mutations in loci adjacent to this allele;one (c.1652G>A)2 with a similar clinical phenotype to our patient and the other (C.625-665 del)3 with primarily inflammatory features and few infections. Impact: This case highlights a variant in IRF2BP2 associated with severe hypogammaglobulinemia, recurrent pulmonary infections, and autoimmune enteropathy. [Table presented]Copyright © 2023 Elsevier Inc.

Newborn-onset chronic urticaria as the first manifestation of NLRP3 mosaicism

Objectives: A 7-month-old boy presented with generalized urticaria since the first week of life, without any other clinical manifestation. Cow's milk allergy was ruled out. His development was normal for his age. Maternal history was significant for COVID-19 infection in the third trimester of pregnancy with mild symptoms. Family history was significant for dermatographism in a maternal uncle. Hives were migratory with no single lesion persisting more than 24 h. There were no recognizable triggers and only relieved for 1-2 days after each vaccination. Patient was treated with optimal doses of antihistamines without improvement. Method(s): Laboratory tests and further studies were performed Results: Laboratory tests were normal including complete blood testing, circulating autoantibodies and infectious studies. C-reactive protein level and erythrocyte sedimentation rate were elevated. Due to chronic urticaria of newborn onset unresponsive to antihistamines a monogenic autoinflammatory disease was suspected. A targeted gene panel covering causative genes revealed the unreported p.Gly307Ala variant in the NLRP3 gene with a variant allele frequency (VAF) of 3% compatible with gene mosaicism. NLRP3 variant was classified as "likely pathogenic" based on its location, where a different variant has been reported as causing a severe form of cryopyrin-associated periodic syndromes (CAPS), and bioinformatic analyses. As expected, the variant was absent in patient's parents supporting for its de novo nature. Vision and hearing exams were normal. Treatment with canakinumab will start soon. Discussion(s): CAPS are dominantly-inherited autoinflammatory diseases caused by gain-of-function NLRP3 variants. These variants are often germline, but in some reported cases the variants are postzygotic causing gene mosaicism as in the patient here described. We believe that the mild presentation in our patient, despite having a likely pathogenic variant, may be explained by the low VAF. The genetic diagnosis in our patient allowed early initiation of anti-IL-1 treatment, which probably will prevent the development of other CAPS manifestations.

A survival genome-wide association study to identify variants associated with COVID-19 risk of death

Background/Objectives: SARS-CoV-2 infection clinical manifestations hugely vary among patients, ranging from no symptoms, to life-threatening conditions. This variability is also due to host genetics: COVID-19 Host Genetics Initiative identified six loci associated with COVID-19 severity in a previous case-control genome-wide association study. A different approach to investigate the genetics of COVID-19 severity is looking for variants associated with mortality, e.g. by analyzing the association between genotypes and time-to-event data. Method(s): Here we perform a case-only genome-wide survival analysis, of 1,777 COVID-19 patients from the GEN-COVID cohort, 60 days after infection/hospitalization. Case-only studies has the advantage of eliminating selection biases and confounding related to control subjects. Patients were genotyped using Illumina Infinium Global Screening Arrays. PLINK software was used for data quality check and principal component analysis. GeneAbel R package was used for survival analysis and age, sex and the first four principal components were used as covariates in the Cox proportional hazard model. Result(s): We found four variants associated with COVID-19 patient survival at a nominal P < 1.0 x 10-6. Their minor alleles were associated with a higher mortality risk (i.e. hazard ratios (HR)>1). In detail, we observed: HR=1.03 for rs28416079 on chromosome 19 (P=1.34 x 10-7), HR=1.15 for rs72815354 on chromosome 10 (P=1.66 x 10-7), HR=2.12 for rs2785631 on chromosome 1 (P=5.14 x 10-7), and HR=2.27 for rs2785631 on chromosome 5 (P=6.65 x 10-7). Conclusion(s): The present results suggest that germline variants are COVID-19 prognostic factors. Replication in the remaining HGI COVID-19 patient cohort (EGAS00001005304) is ongoing at the time of submission.

Association of polymorphic variants in human genome with the COVID-2019 severity and post-COVID syndrome development

Background/Objectives: Despite intensive research of the novel coronavirus SARS-CoV-2 and COVID-2019 caused by it, factors affecting the severity of the disease remains poorly understood. Clinical manifestations of COVID-2019 may vary from asymptomatic form to pneumonia, acute respiratory distress syndrome (ARDS) and multiorgan failure. Features of individual genetic landscape of patients can play an important role in development of the pathological process of COVID-19. In this regard the purpose of this study was to investigate the influence of polymorphic variants in genes (ADD1, CAT, IL17F, IL23R, NOS3, IFNL3, IL6, F2, F13A1, ITGB3, HIF1A, MMP12, VEGFA), associated with cardiovascular, respiratory and autoimmune pathologies, on the severity of COVID-19 and post-COVID syndrome in patients from Russia. Method(s): The study included 200 patients recovered from COVID-19. Two groups of patients were formed in accordance with clinical manifestations: with mild and moderate forms of the disease. The polymorphic variants were analysed with real-time PCR using commercial kits (Syntol). Result(s): 13 SNPs (rs4961;rs1001179;rs612242;rs11209026;rs2070744;rs8099917;rs1800795;rs1799963;rs5985;rs5918;rs11549465;rs652438;rs699947) were genotyped and comparative analysis of allele frequency distribution was carried out in two groups of patients recovered from COVID-2019. Conclusion(s): Identification of polymorphic variants in genome associated with severity of pathological processes in patients infected with SARS-CoV-2 can contribute to the identification of individuals with an increased risk of severe infection process and can also serve as a basis for developing personalized therapeutic approaches to the treatment of post-COVID syndrome.

SARS-CoV-2 sequencing: A comparison of highthroughput methods

Background/Objectives: The COVID-19 pandemic continues to threaten public health and burden healthcare systems worldwide. Whole SARS-CoV-2 genome sequencing has become essential for epidemiological monitoring and identification of new variants, which could represent a risk of increased transmissibility, virulence, or resistance to vaccines or treatment. In this study, we assess the performance of various target enrichment methods for whole SARS-CoV-2 sequencing. Method(s): We applied three target enrichment methods - two multiplex amplification methods and one hybridization capture - to the same set of nasopharyngeal patient samples (N = 93) in high-throughput mode. SARS-CoV-2 genome was obtained using short-read next-generation sequencing. Result(s): All three methods provided excellent breadth of coverage of SARS-CoV-2 genome (above 99%), albeit with vastly different sequencing depth (5-fold difference) and uniformity of coverage (20% difference in coefficient of variation). Poor local coverage has negative impact on variant calling in the concerned region, leading to an occasional allele drop-out (1.2% SNPs affected for one method). Conclusion(s): We discuss the performance of each target enrichment method and their potential for scaling up, in order to promote prospective programs of large-scale genomic surveillance of SARS-CoV-2 worldwide. Genomic surveillance will be crucial to overcoming the ongoing pandemic of COVID-19, despite its successive waves and continually emerging variants.

Italian ancestral HLA haplotype predisposing to severe COVID-19 by low spike and high IFNalpha binding affinity

Background/Objectives: Validated association between COVID-19 and the most obvious candidate genes, e.g. HLA, is still missing. A weak association with class I HLA-C*04:01 was found for infection in Sardinians and for severity in another mixed population. Auto-antibodies to interferon type I have been implicated in the severity of COVID-19 in two studies. Method(s): The binding affinity between HLA molecules and SARS-CoV-2 spike protein and IFNalpha subunits was evaluated in silico. The presence of antibodies against one or more of the 12 IFNalpha subunits was evaluated in 160 hospitalized COVID-19 patients. The 10 most frequent haplotypes in the Italian population were tested in 1.997 SARS-CoV-2 infected patients (hospitalized versus not hospitalized). Result(s): The presence of auto-antibodies against at least one IFNalpha subunit was detected in 26% of patients. The haplotype A*24:02-B*35:02-C*04:01-DRB1*11:04-DQB1*03:01 was found to predispose to severity (p = 0.0018;p = 0.07 after Bonferroni correction) in patients <50 years. The haplotype includes alleles able to bind spike with low affinity (i.e. C*04:01 and DRB1*11:04) and IFNalpha with high affinity (i.e. DRB1*11:04). Conclusion(s): One of the 10 most frequent ancestral haplotype of the Italian population predisposes to severity likely reducing both innate immunity through IFNalpha auto-antibodies induction and adaptive immunity through weaker spike protein presentation.

Identification of genetic determinants of COVID-19 severity by exome sequencing

Background/Objectives: The severity of the symptoms of coronavirus disease 2019 (COVID-19) has been associated to age, comorbidity, and male sex. Besides virus characteristics, host genetic factors influence the infection outcome. Different genome-wide association studies and meta-analyses investigated the contribution of common variants, whereas the role of rare variants just started to be elucidated. Our goal is to determine the contribution of rare variants to the development of severe COVID-19 in the Italian population. Method(s): We compared the genetic background of 215 severe COVID-19 patients with 1764 individuals from the general population. Rare variants (minor allele frequency <1%) from wholeexome sequencing data were retrieved using a bioinformatics variant discovery pipeline. We tested the impact of rare variants (classified according to their predicted effect on the gene product) both using a burden test design, and an iterative machine learning (ML) approach. Result(s): We identified a total of 690,000 rare variants in the entire examined population. Among them, 250 were associated with COVID-19 severity at a nominal P < 0.05. Gene-based burden test revealed a gene with an excess of loss-of-function mutations at P < 0.05. Finally, the ML approach, analysing all the 690,000 rare variants, identified the best combination of variants that is able to predict COVID-19 severity in our cohort. Conclusion(s): Our work provides new insights on the genetic signature of COVID-19 in the Italian population. The most informative rare variants could be exploited to define individuals' risk profiles to COVID-19 severity for the Italian population.

Gain and loss of function CFTR alleles modulate COVID-19 clinical outcome

Background/Objectives: We previously demonstrated that carrying a single pathogenic CFTR allele increases the risk for COVID-19 severity and mortality rate. We now aim to clarify the role of several uncharacterized rare alleles, including complex (cis) alleles, and in trans combinations. Method(s): LASSO logistic regression was used for the association of sets of variants, stratified by MAF, with severity. Immortalized cystic fibrosis bronchial epithelial cell lines and Fischer Rat Thyroid cells were transfected by plasmid carrying specific CFTR mutations. YFP-based assays were used to measure CFTR activity. Result(s): Here we functionally demonstrate that the rare (MAF=0.007) complex G576V/R668C allelemitigates the disease by a gain of function mechanism. Several novel CFTR ultra-rare (MAF <0.001) alleles were proved to have a reduced function;they are associated with disease severity either alone (single or complex alleles) or with another hypomorphic allele in the second chromosome, with a global reduction of CFTR activity between 40 to 72%. Conclusion(s): CFTR is a bidirectional modulator of COVID-19 outcome. At-risk subjects do not have open cystic fibrosis before viral infection and therefore are not easily recognisable in the general population unless a genetic analysis is performed. As the CFTR activity is partially retained, CFTR potentiator drugs could be an option as add-on therapy for at-risk patients.

The Correlation of Single Nucleotide Polymorphism of the ACE2 rs4646116 Gene with The Severity of COVID-19

SUMMARY. Different genetic and immunological factors can affect the severity of Coronavirus disease 19. Angiotensin-converting enzyme 2 is a human receptor for Severe Acute Respiratory Syndrome Coro-navirus-2, and the successful interaction between the spike protein of the novel virus and Angiotensin-converting enzyme 2 is responsible for the initial and complete infection. The study aimed to evaluate the correlation between Single Nucleotide Polymorphisms of Angiotensin converting-enzyme 2, with disease severity of Coronavirus disease 19 in AL-Najaf province. The allele Specific-polymerase Chain reaction method was used for investigating Single Nucleotide polymorphisms of Angiotensin converting-enzyme 2 rs4646116 A/G in different states of Coronavirus disease 19 (COVID-19). The wild genotypes (GG) for ACE2 rs4646116 gene recorded a highly significant association p = 0.0009, and a high ratio in the control group (90%) in comparison with moderate cases of COVID-19 (60%). While the heterozygote genotype (GA) of the same gene showed a significant (p-value = 0.0144) and high ratio in moderate cases (30%) in comparison with the control group (10%). Conclusion(s): the wild genotype (GG) for Angiotensin convert-ing-enzyme 2 rs4646116 gene may be associated with more protection from infection with COVID-19. While the polymorphism heterozygote genotype (GA) for the same gene may be associated with more susceptibility to infection with COVID-19.Copyright © 2023, Colegio de Farmaceuticos de la Provincia de Buenos Aires. All rights reserved.

Emerging Invasive Group A Streptococcus M1UK Lineage Detected by Allele-Specific PCR, England, 20201.

Increasing reports of invasive Streptococcus pyogenes infections mandate surveillance for toxigenic lineage M1UK. An allele-specific PCR was developed to distinguish M1UK from other emm1 strains. The M1UK lineage represented 91% of invasive emm1 isolates in England in 2020. Allele-specific PCR will permit surveillance for M1UK without need for genome sequencing.

Effect of the Angiotensin-Converting Enzyme (ACE) (I/D) Polymorphism in COVID-19 Patients and Their Healthy Contacts.

Introduction The quest to understand the pathophysiology behind the deleterious effects of the coronavirus disease 2019 (COVID-19) outbreak took a turn when involvement of the angiotensin converting enzyme (ACE) receptors in different organs, especially the lungs, could explain all the clinical manifestations and adverse events in patients. The I/D polymorphism in the ACE gene, having been attributed in various studies, was also seen to have an effect in this pandemic. Present study aimed to analyze the effect of this I/D mutation in COVID-19 patients and in their healthy contacts. Methods Patients with past history of COVID-19 infection and their healthy contacts were enrolled in the study after obtaining ethical clearance and informed consent. The polymorphism was studied by real-time polymerase chain reaction (PCR). Data was analyzed in SPSS version 20 (IBM Corp., Armonk, NY, USA). p value less than 0.05 was taken as significant. Results The allelic distribution followed the Hardy-Weinberg equilibrium, with the wild 'D' allele being dominant in the population. Between the case and controls, the mutant 'I' allele was observed more in the controls, and the association was statistically significant. Conclusion From the results of the present study, it could be concluded that while the wild 'D' allele led to higher chances of being affected with COVID-19, the polymorphism to 'I' allele was relatively protective in nature.

Intra-host mutation rate of acute SARS-CoV-2 infection during the initial pandemic wave.

SARS-CoV-2 mutation is minimized through a proofreading function encoded by NSP-14. Most estimates of the SARS-CoV-2 mutation rate are derived from population based sequence data. Our understanding of SARS-CoV-2 evolution might be enhanced through analysis of intra-host viral mutation rates in specific populations. Viral genome analysis was performed between paired samples and mutations quantified at allele frequencies (AF) ≥ 0.25, ≥ 0.5 and ≥ 0.75. Mutation rate was determined employing F81 and JC69 evolution models and compared between isolates with (ΔNSP-14) and without (wtNSP-14) non-synonymous mutations in NSP-14 and by patient comorbidity. Forty paired samples with median interval of 13 days [IQR 8.5-20] were analyzed. The estimated mutation rate by F81 modeling was 93.6 (95%CI 90.8-96.4], 40.7 (95%CI 38.9-42.6) and 34.7 (95%CI 33.0-36.4) substitutions/genome/year at AF ≥ 0.25, ≥ 0.5, ≥ 0.75 respectively. Mutation rate in ΔNSP-14 were significantly elevated at AF ≥ 0.25 vs wtNSP-14. Patients with immune comorbidities had higher mutation rate at all allele frequencies. Intra-host SARS-CoV-2 mutation rates are substantially higher than those reported through population analysis. Virus strains with altered NSP-14 have accelerated mutation rate at low AF. Immunosuppressed patients have elevated mutation rate at all AF. Understanding intra-host virus evolution will aid in current and future pandemic modeling.

Molecular genetics and genomics of the ABO blood group system

The A and B oligosaccharide antigens of the ABO blood group system are produced from the common precursor, H substance, by enzymatic reactions catalyzed by A and B glycosyltransferases (AT and BT) encoded by functional A and B alleles at the ABO genetic locus, respectively. In 1990, my research team cloned human A, B, and O allelic cDNAs. We then demonstrated this central dogma of ABO and opened a new era of molecular genetics. We identified four amino acid substitutions between AT and BT and inactivating mutations in the O alleles, clarifying the allelic basis of ABO. We became the first to achieve successful ABO genotyping, discriminating between AA and AO genotypes and between BB and BO, which was impossible using immunohematological/serological methods. We also identified mutations in several subgroup alleles and also in the cis-AB and B(A) alleles that specify the expression of the A and B antigens by single alleles. Later, other scientists interested in the ABO system characterized many additional ABO alleles. However, the situation has changed drastically in the last decade, due to rapid advances in next-generation sequencing (NGS) technology, which has allowed the sequencing of several thousand genes and even the entire genome in individual experiments. Genome sequencing has revealed not only the exome but also transcription/translation regulatory elements. RNA sequencing determines which genes and spliced transcripts are expressed. Because more than 500,000 human genomes have been sequenced and deposited in sequence databases, bioinformaticians can retrieve and analyze this data without generating it. Now, in this era of genomics, we can harness the vast sequence information to unravel the molecular mechanisms responsible for important biological phenomena associated with the ABO polymorphism. Two examples are presented in this review: the delineation of the ABO gene evolution in a variety of species and the association of single nucleotide variant (SNV) sites in the ABO gene with diseases and biological parameters through genome-wide association studies (GWAS).Copyright © Annals of Blood. All rights reserved.

Development of a New Epitope Immunogenic Structure Based on the Coronavirus Membrane Glycoprotein M Using Immunoinformatics Tools

Backgrounds: Although conventional therapies have played an essential role in the treatment of many diseases, emerging diseases require new treatment methods with less complications. Therefore, it is important to develop an effective vaccine for infections caused by the coronavirus to prevent mortality and create immunity the community. Material(s) and Method(s): In this research bioinformatics tools were used to design a vaccine against the M membrane protein of SARS-CoV-2. A total of 27 epitopes confined to B cells and MHC I and II alleles were structurally constructed in M protein for immune stimulation and antibody recognition which were used in the construction of a chimeric peptide vaccine. Finding(s): The vaccine was predicted to be a stable, antigenic, and non-allergenic compound. TRL5/vaccine complex analysis and docking simulation indicated a sufficiently stable binding with appropriated receptor activation. The immune response simulation following hypothetical immunization indicated the potential of this vaccine to stimulate the production of active and memory B cells, CD8 + T and, CD4 + T cells, and effective immunological responses induced by Th2 and Th1. Conclusion(s): The analysis of in-silico processes showed that the vaccine structure induced high antigenicity and good cellular immunity in the host body and stimulates various immune receptors such as TLR5, MHC I, and MHC II. Vaccine function was also associated with an increase in IgM and IgG antibodies and a set of Th1 and Th2 cytokines. But the final confirmation of the effectiveness of the designed vaccine requires clinical processes.Copyright © 2022, TMU Press.

Optimized nanoparticle-mediated base editing of cystic fibrosis-causing variants

Background: Next-generation SARS-CoV-2 vaccines demonstrated that nanoparticle messenger ribonucleic acid (mRNA) delivery is effective and safe for in vivo delivery in humans. Current treatments for cystic fibrosis (CF) primarily focus on modulator drug therapies designed to correct malfunctioning CF transmembrane conductance regulator (CFTR) protein, but these modulators are ineffective for the 10% of people with CF with variants that do not allow protein production. Among these is the splice variant 3120 + 1G >A, the most common CF-causing mutation in native Africans. Gene editing would allow production of CFTR protein and enhancement of function using available CFTR modulators. We have demonstrated that electroporation of a modified CRISPR-Cas9 base editor to primary human bronchial epithelial cells carrying 3120 + 1G >A and F508del mutant alleles achieved 75% genome editing of the splice variant, resulting in approximately 40% wild-type (WT) CFTR function [1]. Here,we evaluate the effectiveness of several new nanoparticle formulations at delivering green fluorescent protein (GFP) mRNA to CF bronchial epithelial (CFBE41o-) cells. Using the optimal formulation,we then tested the efficacy correction of the 3120 + 1G >Avariant in a CFTR expression minigene (EMG) integrated into the genome of isogenic CFBE cells using mRNA and plasmid deoxyribonucleic acid (DNA) encoding adenine base editor (ABE) and guide (g)RNA. Method(s): GFP served as a reporter to evaluate transfection efficiency, cell viability, and mean fluorescence intensity (MFI) for three dosages (150, 75, 32.5 ng of mRNA), four polymer-to-mRNA to weight (w/w) ratios (60, 40, 30, 20), and four polymers (R, Y, G, B). 7-AAD served as a live/dead stain to quantify viability, with flow cytometry results analyzed using FlowJo software. CFBE cells stably expressing the 3120 + 1G >A EMG were transfected with the optimized nanoparticle formulation to deliver ABE and gRNA at two dosages (150, 75 ng) of mRNA and DNA. CFTR function in CFBE cellswas measured by short circuit current, forskolin stimulation, and inh-172 inhibition as a measure of editing efficiency. Result(s): Flow cytometry showed that polymer R achieved more than 85% GFP transfection, compared with a maximum of approximately 35% for the other three polymers at the maximum 150-ng dose, with approximately 80% viability normalized to untreated cells. In addition, polymer R achieved GFP MFI more than one order of magnitude as high as other formulations (~30 000 vs 2700 MFI) for the other three polymers at 150-ng dose and 40 w/w ratio. CFBE cells transfected with polymer R nanoparticles containing ABE and guide RNA at 75 ng and 150 ng showed mean CFTR function increase to 10 muA 6 (standard error of the mean [SEM] 1.1 muA) (~10% of WT) and 6.3 muA (SEM 0.9 muA) (~6% of WT), respectively. Greater toxicity at the higher dose could explain the larger increase in CFTR current at the lower dose. DNA-encoded ABE plasmid and gRNA showed a less robust increase in CFTR function (2.9 muA [SEM 0.4 muA] for 75-ng dose;3.0 muA [SEM 0.4 muA] for 150-ng dose), which was probably a result of the nanoparticle formulation being optimized for RNA instead of DNA cargo or the additional intracellular barriers that must be overcome for successful DNA delivery. Conclusion(s): We demonstrated that an optimized nanoparticle formulation containing ABE and gRNA can correct splicing of isogenic cells bearing the 3120 + 1G >A CFTR variant, resulting in recovery of CFTR function. In ongoing work, we are adapting these nanoparticles for RNA- and DNAencoded ABE and gRNA delivery to primary human bronchial epithelial cells.Copyright © 2022, European Cystic Fibrosis Society. All rights reserved

Association of Toll-Like Receptor 7 and 8 Polymorphisms with Covid-19 Severity

Objectives: Toll-like receptors (TLRs) are an important family of receptors that recognize infectious agents and play an important role in the innate immune system. TLRs are a potential candidate to control infection in the early stages of the disease and to produce vaccines against SARS-CoV-2. In addition, studies have suggested that TLR polymorphisms are also associated with antiviral responses against SARS-CoV-2. Therefore, we aimed to investigate the relationship of TLR7 and TLR8 polymorphisms with COVID-19 disease prognosis. Materials-Methods: A total of 120 COVID-19 patients, including 40 outpatients, 40 patients with mild and moderate clinical status, hospitalized and severe pneumonia, and 40 patients followed in the intensive care unit (ICU), were included in the study. The classification of disease severity was made according to WHO criteria. TLR7 (rs179009), TLR8 -129 C/G (rs3764879) and TLR8 Met1Val (rs3764880) polymorphisms were genotyped using the PCR-RFLP method. Result(s): Since TLR7 and TLR8 are located on the X chromosome, men and women were analyzed separately. There was no significant difference between the groups in terms of 3 polymorphisms in males. On the other hand, in women, individuals carrying AG genotype and G allele for TLR8 Met1Val polymorphism were found at a higher rate in patients hospitalized in ICU than in patients followed in the service (p <0.05). In terms of the other two polymorphisms, no significant difference was found between the groups in women. Conclusion(s): We suggest that the AG genotype and G allele of TLR8 Met1Val polymorphism can be considered as an important risk factor that increases the severity of the disease in women.

HLA-A*03:01 significantly predicts strong humoral response at six months after mRNA vaccination: Results from the observational prospective cohort study RENAISSANCE

While several studies have been conducted on HLA and Covid-19 infection, few investigated the role of HLA polymorphism on vaccination response. We previously analyzed the HLA allele and haplotype frequencies in a hundred weak responders (antibody levels <5th percentile) after mRNA anti-Covid vaccine and found some suggestions about specific alleles and one haplotype. We moved on typing individuals enrolled in the same cohort study ("RENAISSANCE") with antibody titers above the 95th percentile at six months after vaccination, in order to search for any alleles predictive of strong humoral response. Individuals with clinical history of COVID-19 or positive anti-nucleocapsid antibodies were excluded. Allelic frequencies were compared with those of weak responders and of the general population, taken from the national bone marrow donor registry, IBMDR. N = 123 evaluable individuals presented with >95th percentile antibody titers at six months after BNT162b2 vaccine. One-third of them had >2080 BAU/mL, lowest value was 1261 BAU/mL. Comparison of allelic frequencies with weak responders showed a significant different proportion of individuals carrying A*03:01, A*24:02 and DRB1*16:01 (21.5% vs. 3.6%, 7.7% vs. 14.9% and 3.2% vs. 8.1% respectively). Moreover, when looking at alleles of the ancestral haplotype A3-B35-C4-DR1, we observed frequencies of 4.47%, 0.84% and 0% in the present cohort, IBMDR and weak responders, respectively. After adjusting for age, gender and BMI, the presence of A*03:01 confirmed to be statistically significant (p<0.0001) and was predictive of high antibody titers at six months with an odds ratio of 12.5 with respect to weak antibody levels. Age was the only other significant variable, with an odds ratio of 0.96. Clinical collection data is underway to correlate Covid-19 infection rates in both cohorts, in an attempt to find a definite correlation between HLA and vaccine protection.