Human Leukocyte Antigen Complex and Other Immunogenetic and Clinical Factors Influence Susceptibility or Protection to SARS-CoV-2 Infection and Severity of the Disease Course. The Sardinian Experience

Aim: SARS-CoV-2 infection is a world-wide public health problem. Several aspects of its pathogenesis and the related clinical consequences still need elucidation. In Italy, Sardinia has had very low numbers of infections. Taking advantage of the low genetic polymorphism in the Sardinian population, we analyzed clinical, genetic and immunogenetic factors, with particular attention to HLA class I and II molecules, to evaluate their influence on susceptibility to SARS-CoV-2 infection and the clinical outcome. Method and Materials: We recruited 619 healthy Sardinian controls and 182 SARS-CoV-2 patients. Thirty-nine patients required hospital care and 143 were without symptoms, pauci-symptomatic or with mild disease. For all participants, we collected demographic and clinical data and analyzed the HLA allele and haplotype frequencies. Results: Male sex and older age were more frequent in hospitalized patients, none of whom had been vaccinated during the previous seasonal flu vaccination campaignes. Compared to the group of asymptomatic or pauci-symptomatic patients, hospitalized patients also had a higher frequency of autoimmune diseases and glucose-6-phosphate-dehydrogenase (G6PDH) deficiency. None of these patients carried the beta-thalassemia trait, a relatively common finding in the Sardinian population. The extended haplotype HLA-A*02:05, B*58:01, C*07:01, DRB1*03:01 [OR 0.1 (95% CI 0–0.6), Pc = 0.015] was absent in all 182 patients, while the HLA-C*04:01 allele and the three-loci haplotype HLA-A*30:02, B*14:02, C*08:02 [OR 3.8 (95% CI 1.8–8.1), Pc = 0.025] were more frequently represented in patients than controls. In a comparison between in-patients and home care patients, the HLA-DRB1*08:01 allele was exclusively present in the hospitalized patients [OR > 2.5 (95% CI 2.7–220.6), Pc = 0.024]. Conclusion: The data emerging from our study suggest that the extended haplotype HLA-A*02:05, B*58:01, C*07:01, DRB1*03:01 has a protective effect against SARS-CoV-2 infection in the Sardinian population. Genetic factors that resulted to have a negative influence on the disease course were presence of the HLA-DRB1*08:01 allele and G6PDH deficiency, but not the beta-thalassemic trait. Absence of influenza vaccination could be a predisposing factor for more severe disease

Natural killer-cell immunoglobulin-like receptors trigger differences in immune response to SARS-CoV-2 infection

Background: The diversity in the clinical course of COVID-19 has been related to differences in innate and adaptative immune response mechanisms. Natural killer (NK) lymphocytes are critical protagonists of human host defense against viral infections. It would seem that reduced circulating levels of these cells have an impact on COVID-19 progression and severity. Their activity is strongly regulated by killer-cell immuno-globulin-like receptors (KIRs) expressed on the NK cell surface. The present study's focus was to investigate the impact of KIRs and their HLA Class I ligands on SARS-CoV-2 infection. Methods: KIR gene frequencies, KIR haplotypes, KIR ligands and combinations of KIRs and their HLA Class I ligands were investigated in 396 Sardinian patients with SARS-CoV-2 infection. Comparisons were made between 2 groups of patients divided according to disease severity: 240 patients were symptomatic or paucisymptomatic (Group A), 156 hospitalized patients had severe disease (Group S). The immunogenetic characteristics of patients were also compared to a population group of 400 individuals from the same geographical areas. Results: Substantial differences were obtained for KIR genes, KIR haplotypes and KIR-HLA ligand combinations when comparing patients of Group S to those of Group A. Patients in Group S had a statistically significant higher frequency of the KIR A/A haplotype compared to patients in Group A [34.6% vs 23.8%, OR = 1.7 (95% CI 1.1-2.6); P = 0.02, Pc = 0.04]. Moreover, the KIR2DS2/HLA C1 combination was poorly represented in the group of patients with severe symptoms compared to those of the asymptomatic-paucisymptomatic group [33.3% vs 50.0%, OR = 0.5 (95% CI 0.3-0.8), P = 0.001, Pc = 0.002]. Multivariate analysis confirmed that, regardless of the sex and age of the patients, the latter genetic variable correlated with a less severe disease course [ORM = 0.4 (95% CI 0.3-0.7), PM = 0.0005, PMC = 0.005]. Conclusions: The KIR2DS2/HLA C1 functional unit resulted to have a strong protective effect against the adverse outcomes of COVID-19. Combined to other well known factors such as advanced age, male sex and concomitant autoimmune diseases, this marker could prove to be highly informative of the disease course and thus enable the timely intervention needed to reduce the mortality associated with the severe forms of SARS-CoV-2 infection. However, larger studies in other populations as well as experimental functional studies will be needed to confirm our findings and further pursue the effect of KIR receptors on NK cell immune-mediated response to SARS-Cov-2 infection

COVID-19 IN THE MEDITERRANEAN AREA: EPIDEMIOLOGY AND MAIN DISEASE CHARACTERISTICS - A NARRATIVE REVIEW

In December 2019, Chinese researchers identified a novel coronavirus in humans that caused acute respiratory syndrome— officially called coronavirus disease (COVID-19) as of February 11, 2020. At the beginning of the outbreak, the Mediterranean countries seemed to be spared from the health and social disaster happened in China. Quickly the spread of the virus ran faster than forecasts and Italy was unfortunately followed by Spain, France and other countries counting many cases and deaths. The World Health Organization declaring COVID-19 a pandemic on March 11th, 2020. A retrospective analysis of big data from Google Trend, using an infodemiology approach, shows how internet traffic search on COVID-19 may figure on the spread curve. The clinical aspects of COVID-19 raises from poor of mild symptomatic patients to severe respiratory disease which can quickly lead patients to respiratory failure and admission to intensive care units. Multi-organ symptoms and different types of involvement other than respiratory have been described. Nowadays the vaccination is still under investigation and there is not a specific treatment approved for COVID–19, but the literature highlights the role of Cloroquine and its less toxic derivative Hydroxychloroquine in the therapeutical management of COVID-19. Those drugs have been proposed as a potential treatment for COVID-19 and clinical trials are undergoing to evaluate this drug. However these drugs have known oxidative properties that could decrease glutathione levels and may cause severe hemolysis in G6PD-deficient patients. Deficient G6PD alleles are distributed worldwide; a conservative estimate is that at least 400 million people carry a mutation in the G6PD gene causing deficiency, the Mediterranean most frequent variant is a class II allele (1-10% of residual activity). With worldwide spread of COVID-19, also in regions with a high prevalence of G6PD deficiency, physicians should be aware of this possible correlation

Low dose aspirin and clinical outcomes in patients with SARS-CoV-2 pneumonia: a propensity score-matched cohort analysis from the National SIMI‑COVID‑19 Registry

Background: SARS- CoV-2 virus has had dramatic consequences worldwide being able to cause acute respiratory distress syndrome (ARDS), massive thrombosis and pulmonary embolism and, finally, patients' death. In COVID-19 infection, platelets have a procoagulant phenotype that can cause thrombosis in the pulmonary and systemic vascular network. Aspirin is a well-known anti-platelet drug widely used for the prevention of cardiovascular events and systematic reviews suggest a possible benefit of low-dose aspirin (LDA) use in the prevention and treatment of ARDS in patients with COVID-19 infection. However, several studies are available in the literature which do not support any benefits and no association with the patients' outcome. Therefore, currently available data are inconclusive. Materials and patients: Data from the nationwide cohort multicenter study of the Italian Society of Internal Medicine (SIMI) were analyzed. We conducted a propensity score-matched cohort analysis to investigate the impact of chronic assumption of LDA on mortality of adult COVID-19 patients admitted in Internal Medicine Units (IMU). Data from 3044 COVID-19 patients who referred to 41 Italian hospitals between February 3rd to May 8th 2020 were analyzed. A propensity score-matched analysis was conducted using the following variables: age, sex, hypertension, hyperlipidemia diabetes, atrial fibrillation, cerebrovascular disease, COPD, CKD and stratified upon LDA usage, excluding anticoagulant treatment. After matching, 380 patients were included in the final analysis (190 in LDA group and 190 in no-LDA group). Results: 66.2% were male, median age was 77 [70-83]. 34.8% of the population died during the hospitalization. Cardiovascular diseases were not significantly different between the groups. After comparison of LDA and no-LDA subgroups, we didn't record a significant difference in mortality rate (35.7% vs 33.7%) duration of hospital stay and ICU admission. In a logistic regression model, age (OR 1.05; 95% CI 1.01-1.09), FiO2 (OR 1.024; 95% CI 1.03-1.04) and days between symptoms onset and hospitalization (OR 0.93; 95% CI 0.87-0.99) were the only variables independently associated with death

YY1 haploinsufficiency causes an intellectual disability syndrome featuring transcriptional and chromatin dysfunction

Yin and yang 1 (YY1) is a well-known zinc-finger transcription factor with crucial roles in normal development and malignancy. YY1 acts both as a repressor and as an activator of gene expression. We have identified 23 individuals with de novo mutations or deletions of YY1 and phenotypic features that define a syndrome of cognitive impairment, behavioral alterations, intrauterine growth restriction, feeding problems, and various congenital malformations. Our combined clinical and molecular data define “YY1 syndrome” as a haploinsufficiency syndrome. Through immunoprecipitation of YY1-bound chromatin from affected individuals’ cells with antibodies recognizing both ends of the protein, we show that YY1 deletions and missense mutations lead to a global loss of YY1 binding with a preferential retention at high-occupancy sites. Finally, we uncover a widespread loss of H3K27 acetylation in particular on the YY1-bound enhancers, underscoring a crucial role for YY1 in enhancer regulation. Collectively, these results define a clinical syndrome caused by haploinsufficiency of YY1 through dysregulation of key transcriptional regulators

Antihypertensive treatment changes and related clinical outcomes in older hospitalized patients

Background: Hypertension management in older patients represents a challenge, particularly when hospitalized. Objective: The objective of this study is to investigate the determinants and related outcomes of antihypertensive drug prescription in a cohort of older hospitalized patients. Methods: A total of 5671 patients from REPOSI (a prospective multicentre observational register of older Italian in-patients from internal medicine or geriatric wards) were considered; 4377 (77.2%) were hypertensive. Minimum treatment (MT) for hypertension was defined according to the 2018 ESC guidelines [an angiotensin-converting-enzyme-inhibitor (ACE-I) or an angiotensin-receptor-blocker (ARB) with a calcium-channel-blocker (CCB) and/or a thiazide diuretic; if >80 years old, an ACE-I or ARB or CCB or thiazide diuretic]. Determinants of MT discontinuation at discharge were assessed. Study outcomes were any cause rehospitalization/all cause death, all-cause death, cardiovascular (CV) hospitalization/death, CV death, non-CV death, evaluated according to the presence of MT at discharge. Results: Hypertensive patients were older than normotensives, with a more impaired functional status, higher burden of comorbidity and polypharmacy. A total of 2233 patients were on MT at admission, 1766 were on MT at discharge. Discontinuation of MT was associated with the presence of comorbidities (lower odds for diabetes, higher odds for chronic kidney disease and dementia). An adjusted multivariable logistic regression analysis showed that MT for hypertension at discharge was associated with lower risk of all-cause death, all-cause death/hospitalization, CV death, CV death/hospitalization and non-CV death. Conclusions: Guidelines-suggested MT for hypertension at discharge is associated with a lower risk of adverse clinical outcomes. Nevertheless, changes in antihypertensive treatment still occur in a significant proportion of older hospitalized patients