A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection.

Studies have demonstrated that at least 20% of individuals infected with SARS-CoV-2 remain asymptomatic1-4. Although most global efforts have focused on severe illness in COVID-19, examining asymptomatic infection provides a unique opportunity to consider early immunological features that promote rapid viral clearance. Here, postulating that variation in the human leukocyte antigen (HLA) loci may underly processes mediating asymptomatic infection, we enrolled 29,947 individuals, for whom high-resolution HLA genotyping data were available, in a smartphone-based study designed to track COVID-19 symptoms and outcomes. Our discovery cohort (n = 1,428) comprised unvaccinated individuals who reported a positive test result for SARS-CoV-2. We tested for association of five HLA loci with disease course and identified a strong association between HLA-B*15:01 and asymptomatic infection, observed in two independent cohorts. Suggesting that this genetic association is due to pre-existing T cell immunity, we show that T cells from pre-pandemic samples from individuals carrying HLA-B*15:01 were reactive to the immunodominant SARS-CoV-2 S-derived peptide NQKLIANQF. The majority of the reactive T cells displayed a memory phenotype, were highly polyfunctional and were cross-reactive to a peptide derived from seasonal coronaviruses. The crystal structure of HLA-B*15:01-peptide complexes demonstrates that the peptides NQKLIANQF and NQKLIANAF (from OC43-CoV and HKU1-CoV) share a similar ability to be stabilized and presented by HLA-B*15:01. Finally, we show that the structural similarity of the peptides underpins T cell cross-reactivity of high-affinity public T cell receptors, providing the molecular basis for HLA-B*15:01-mediated pre-existing immunity.

Protracted yet Coordinated Differentiation of Long-Lived SARS-CoV-2-Specific CD8+ T Cells during Convalescence.

CD8+ T cells can potentiate long-lived immunity against COVID-19. We screened longitudinally-sampled convalescent human donors against SARS-CoV-2 tetramers and identified a participant with an immunodominant response against residues 322 to 311 of nucleocapsid (Nuc322-331), a peptide conserved in all variants of concern reported to date. We conducted 38-parameter cytometry by time of flight on tetramer-identified Nuc322-331-specific CD8+ T cells and on CD4+ and CD8+ T cells recognizing the entire nucleocapsid and spike proteins, and took 32 serological measurements. We discovered a coordination of the Nuc322-331-specific CD8+ T response with both the CD4+ T cell and Ab pillars of adaptive immunity. Over the approximately six month period of convalescence monitored, we observed a slow and progressive decrease in the activation state and polyfunctionality of Nuc322-331-specific CD8+ T cells, accompanied by an increase in their lymph node-homing and homeostatic proliferation potential. These results suggest that following a typical case of mild COVID-19, SARS-CoV-2-specific CD8+ T cells not only persist but continuously differentiate in a coordinated fashion well into convalescence into a state characteristic of long-lived, self-renewing memory.

Virtual clinics in gynaecology - Can we shorten the wait? A randomised controlled trial implementing a novel care pathway for postmenopausal bleeding.

BACKGROUND: Postmenopausal bleeding (PMB), a common symptom of endometrial cancer, necessitates prompt clinical and sonographic assessment, often followed by hysteroscopy. Unfortunately, due to traditional gynaecology outpatient clinic paradigms, unnecessary patient-clinician encounters are common and may lead to delays in diagnosis. AIM: The aim was to assess a novel clinic model for the management of women with PMB based on virtual assessment and routine use of the outpatient hysteroscopy clinic. METHODS: An unblinded pragmatic randomised controlled trial was performed, comparing a 'virtual clinic' to routine outpatient clinical care. The primary outcome for assessment was time, measured as the interval (days) between referral triage and discharge for definitive management or to the general practitioner. Demographical and clinical data were collected. After discharge from the system, patients completed a satisfaction and feedback questionnaire. Log-rank tests were used to compare the equality of time-to-event functions across randomised groups. RESULTS: There were 96 participants, 46 in the intervention arm and 50 controls. The total time spent in the gynaecology system differed between groups (Χ2 (1) = 6.94, P = 0.008), with a median total time of 55 days (95% confidence interval (CI): 37-66 days) for the intervention group compared to a median of 84 days (95% CI: 54-101 days) for the control group. The number of in-person gynaecology encounters differed between those randomised to intervention (P < 0.001). Overall, 96% of respondents indicated a positive score for overall satisfaction. CONCLUSIONS: The proposed clinic model resulted in a significant reduction in the time between referral and discharge, without compromising patient satisfaction.

Determining a threshold measurement of endometrial thickness for asymptomatic postmenopausal women: A tertiary centre case series.

BACKGROUND: An incidental finding of a thickened endometrium on ultrasound in the postmenopausal patient without bleeding is a common presentation to gynaecological services; however there is limited evidence to guide clinical practice as to when hysteroscopic evaluation and endometrial sampling is required. AIMS: To determine the endometrial thickness at which endometrial sampling is indicated in asymptomatic postmenopausal women referred with thickened endometrium on ultrasound. MATERIALS AND METHODS: A single-centre retrospective case series of postmenopausal women without bleeding undergoing hysteroscopy was conducted. Logistic regression was used to examine the association between a range of variables and pre-malignant or malignant pathology and endometrial thickness. The optimal endometrial thickness threshold was identified to maximise model sensitivity. RESULTS: A total of 404 postmenopausal women were included in this study, having undergone a hysteroscopy at the study site between 1 July 2008 and 30 June 2018. The mean (SD) age of patients at presentation was 65 (9.09) years and the mean body mass index was 29.86 kg/m2 (6.52). Of these women, nine (2.2%) were diagnosed with endometrial carcinoma and seven (1.7%) had endometrial hyperplasia with atypia. The most common histopathological finding was of a benign endometrial polyp (153: 37.9%). When including hyperplasia with or without atypia in histopathology of interest, a cut-off of ≥9 mm provides the greatest sensitivity (83.3%) and specificity (63.8%) for a diagnosis of pre-malignant or malignant pathology (classification accuracy of 64.8%; area under the receiver operating characteristic: 0.7358, 95% CI: 0.6439, 0.8278) in this cohort. CONCLUSIONS: Using an endometrial thickness of ≥9 mm can be used as a cut-off for endometrial sampling in postmenopausal women without bleeding.

Risk of Breast Cancer After Diabetes in Pregnancy: A Population-based Cohort Study.

OBJECTIVES: Diabetes is associated with an increased risk of several cancers, including postmenopausal breast cancer. The evidence for higher breast cancer risk after diabetes in pregnancy is conflicting. We compared the incidence of breast and other cancers between pregnant women with and without diabetes. METHODS: This work was a propensity-matched, retrospective cohort study using population-based health-care databases from Ontario, Canada. Those deliveries with gestational diabetes mellitus (GDM) and pregestational diabetes mellitus (pregestational DM) were identified and matched to deliveries without diabetes mellitus (non-DM). Deliveries from each diabetes cohort were matched 1:2 on age, parity, year of delivery, and propensity score to non-DM deliveries. Matched subjects were followed from delivery for incidence of breast cancer as a primary outcome, and other site-specific cancers as secondary outcomes. We performed Cox proportional hazards regression to compare rates of breast cancer between matched groups. RESULTS: Over a median of 8 (interquartile range 4 to 13) years of follow-up, compared with non-DM deliveries, the incidence of breast cancer was significantly lower for GDM but similar for pregestational DM deliveries (hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.82 to 0.98; and HR 0.92, 95% CI 0.80 to 1.07, respectively). GDM was associated with a significantly higher incidence of pancreatic and hepatocellular cancer, and pregestational DM was associated with a higher incidence of thyroid, hepatocellular, and endometrial cancers. CONCLUSIONS: Diabetes in pregnancy does not have a higher short-term risk of subsequent breast cancer, but there may be a higher incidence of other cancers.

From skillful to empathic: evaluating shifts in medical students' perceptions of surgeons through a combined patient as teacher and arts-based reflection program.

Introduction: The purpose of this study was to identify whether the incorporation of a combined Patient as teacher (PAT) and arts-based reflection (ABR) program during a surgical clerkship rotation could influence more humanistic perceptions of surgeons, using an innovative evaluation approach. Methods: A novel, single question evaluation tool was created. Third year medical-students were asked to "list the top 5 attributes of a surgeon, in order of perceived importance" both before and after their surgical clerkship rotations and participation in the PAT/ABR program. Attributes identified by students were coded as either "humanistic" or "non-humanistic," which were then analyzed using generalized linear regression models under a Bayesian framework. Results: After participation in the PAT/ABR program, the predicted probability of students ranking a humanistic characteristic as the most important attribute of a surgeon had increased by 17%, and the predicted probability of students ranking a humanistic characteristic amongst their top three attributes for a surgeon had increased by 21%. Conclusion: This innovative evaluative method suggested the success of a combined PAT/ABR program in encouraging a humanistic perspective of surgery and this approach could potentially be explored to evaluate other humanistic education initiatives.

Introduction: L'objectif de cette étude était de déterminer si l'introduction d'une nouvelle approche d'évaluation associant la participation de Patients comme enseignants (PCE) à une Réflexion basée sur les arts (RBA) dans un stage d'externat en chirurgie permettait de mieux percevoir les qualités humanistes chez les chirurgiens. Méthodes: Un nouvel outil d'évaluation à question unique a été créé. Des étudiants en troisième année de médecine ont été invités à ''énumérer les cinq principaux attributs d'un chirurgien, par ordre d'importance perçue'', avant et après leur stage d'externat en chirurgie et le programme PCE/RBA. Les attributs identifiés par les étudiants ont été codés comme « humanistes ¼ ou « non humanistes ¼, puis analysés à l'aide de modèles de régression linéaire généralisée dans un cadre bayésien. Résultats: Après leur participation au programme PCE/RBA, la probabilité prédite moyenne que les étudiants classent un trait humaniste comme l'attribut le plus important d'un chirurgien a augmenté de 17 %, et la probabilité prédite que les étudiants classent un trait humaniste parmi les trois premiers attributs d'un chirurgien a augmenté de 21 %. Conclusion: Cette méthode d'évaluation innovante porte à croire que le programme PCE/RBA réussit en effet à favoriser une vision humaniste de la chirurgie. Cette approche peut être explorée pour évaluer d'autres activités de formation axées sur l'humanisme.

A common allele of HLA mediates asymptomatic SARS-CoV-2 infection.

Despite some inconsistent reporting of symptoms, studies have demonstrated that at least 20% of individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will remain asymptomatic. Although most global efforts have focused on understanding factors underlying severe illness in COVID-19 (coronavirus disease of 2019), the examination of asymptomatic infection provides a unique opportunity to consider early disease and immunologic features promoting rapid viral clearance. Owing to its critical role in the immune response, we postulated that variation in the human leukocyte antigen (HLA) loci may underly processes mediating asymptomatic infection. We enrolled 29,947 individuals registered in the National Marrow Donor Program for whom high-resolution HLA genotyping data were available in the UCSF Citizen Science smartphone-based study designed to track COVID-19 symptoms and outcomes. Our discovery cohort (n=1428) was comprised of unvaccinated, self-identified subjects who reported a positive test result for SARS-CoV-2. We tested for association of five HLA loci (HLA-A, -B, -C, -DRB1, -DQB1) with disease course and identified a strong association of HLA-B*15:01 with asymptomatic infection, and reproduced this association in two independent cohorts. Suggesting that this genetic association is due to pre-existing T-cell immunity, we show that T cells from pre-pandemic individuals carrying HLA-B*15:01 were reactive to the immunodominant SARS-CoV-2 S-derived peptide NQKLIANQF, and 100% of the reactive cells displayed memory phenotype. Finally, we characterize the protein structure of HLA-B*15:01-peptide complexes, demonstrating that the NQKLIANQF peptide from SARS-CoV-2, and the highly homologous NQKLIANAF from seasonal coronaviruses OC43-CoV and HKU1-CoV, share similar ability to be stabilized and presented by HLA-B*15:01, providing the molecular basis for T-cell cross-reactivity and HLA-B*15:01-mediated pre-existing immunity.

Distinctive features of SARS-CoV-2-specific T cells predict recovery from severe COVID-19.

Although T cells are likely players in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity, little is known about the phenotypic features of SARS-CoV-2-specific T cells associated with recovery from severe coronavirus disease 2019 (COVID-19). We analyze T cells from 34 individuals with COVID-19 with severity ranging from mild (outpatient) to critical, culminating in death. Relative to individuals who succumbed, individuals who recovered from severe COVID-19 harbor elevated and increasing numbers of SARS-CoV-2-specific T cells capable of homeostatic proliferation. In contrast, fatal COVID-19 cases display elevated numbers of SARS-CoV-2-specific regulatory T cells and a time-dependent escalation in activated bystander CXCR4+ T cells, as assessed by longitudinal sampling. Together with the demonstration of increased proportions of inflammatory CXCR4+ T cells in the lungs of individuals with severe COVID-19, these results support a model where lung-homing T cells activated through bystander effects contribute to immunopathology, whereas a robust, non-suppressive SARS-CoV-2-specific T cell response limits pathogenesis and promotes recovery from severe COVID-19.

Protracted yet coordinated differentiation of long-lived SARS-CoV-2-specific CD8+ T cells during COVID-19 convalescence.

CD8+ T cells are important antiviral effectors that can potentiate long-lived immunity against COVID-19, but a detailed characterization of these cells has been hampered by technical challenges. We screened 21 well-characterized, longitudinally-sampled convalescent donors that recovered from mild COVID-19 against a collection of SARS-CoV-2 tetramers, and identified one participant with an immunodominant response against Nuc322-331, a peptide that is conserved in all the SARS-CoV-2 variants-of-concern reported to date. We conducted 38-parameter CyTOF phenotyping on tetramer-identified Nuc322-331-specific CD8+ T cells, and on CD4+ and CD8+ T cells recognizing the entire nucleocapsid and spike proteins from SARS-CoV-2, and took 32 serological measurements on longitudinal specimens from this participant. We discovered a coordination of the Nuc322-331-specific CD8+ T response with both the CD4+ T cell and antibody pillars of adaptive immunity. Nuc322-331-specific CD8+ T cells were predominantly central memory T cells, but continually evolved over a ~6-month period of convalescence. We observed a slow and progressive decrease in the activation state and polyfunctionality of the Nuc322-331-specific CD8+ T cells, accompanied by an increase in their lymph-node homing and homeostatic proliferation potential. These results suggest that following a typical case of mild COVID-19, SARS-CoV-2-specific CD8+ T cells not only persist but continuously differentiate in a coordinated fashion well into convalescence, into a state characteristic of long-lived, self-renewing memory.

Distinctive features of SARS-CoV-2-specific T cells predict recovery from severe COVID-19.

Although T cells are likely players in SARS-CoV-2 immunity, little is known about the phenotypic features of SARS-CoV-2-specific T cells associated with recovery from severe COVID-19. We analyzed T cells from longitudinal specimens of 34 COVID-19 patients with severities ranging from mild (outpatient) to critical culminating in death. Relative to patients that succumbed, individuals that recovered from severe COVID-19 harbored elevated and increasing numbers of SARS-CoV-2-specific T cells capable of homeostatic proliferation. In contrast, fatal COVID-19 displayed elevated numbers of SARS-CoV-2-specific regulatory T cells and a time-dependent escalation in activated bystander CXCR4+ T cells. Together with the demonstration of increased proportions of inflammatory CXCR4+ T cells in the lungs of severe COVID-19 patients, these results support a model whereby lung-homing T cells activated through bystander effects contribute to immunopathology, while a robust, non-suppressive SARS-CoV-2-specific T cell response limits pathogenesis and promotes recovery from severe COVID-19.

SARS-CoV-2-specific T cells exhibit unique features reflecting robust helper function, lack of terminal differentiation, and high proliferative potential.

Convalescing COVID-19 patients mount robust T cell responses against SARS-CoV-2, suggesting an important role for T cells in viral clearance. To date, the phenotypes of SARS-CoV-2-specific T cells remain poorly defined. Using 38-parameter CyTOF, we phenotyped longitudinal specimens of SARS-CoV-2-specific CD4+ and CD8+ T cells from nine individuals who recovered from mild COVID-19. SARS-CoV-2-specific CD4+ T cells were exclusively Th1 cells, and predominantly Tcm with phenotypic features of robust helper function. SARS-CoV-2-specific CD8+ T cells were predominantly Temra cells in a state of less terminal differentiation than most Temra cells. Subsets of SARS-CoV-2-specific T cells express CD127, can homeostatically proliferate, and can persist for over two months. Our results suggest that long-lived and robust T cell immunity is generated following natural SARS-CoV-2 infection, and support an important role for SARS-CoV-2-specific T cells in host control of COVID-19.

Routine Blood Tests in Asymptomatic Patients With Indolent Lymphoma Have Limited Ability to Detect Clinically Significant Disease Progression.

PURPOSE: Patients with indolent non-Hodgkin lymphoma (iNHL) undergo regular active surveillance in between treatment periods to detect disease relapse or progression. As part of surveillance, international guidelines recommend regular routine blood testing, which is based on consensus rather than evidence of utility. METHODS: We conducted a retrospective analysis of all patients older than age 16 years diagnosed with grade 1-3A follicular or marginal zone lymphoma between 2008 and 2017 from 2 Australian cancer centers to assess the utility of full blood examination, lactate dehydrogenase, and ß2-microglobulin in detecting progression events, defined as either disease relapse or progression of disease. RESULTS: One hundred eighty patients attended 1,757 outpatient appointments (median follow-up, 36 months). Routine blood tests (RBTs) were performed before 83% of appointments. Seventy-four progression events occurred in 62 patients. Only 2 events (3%) were detected by RBTs alone, both of which occurred in treatment-naïve patients who subsequently developed symptoms within 3 weeks. The remainder of progression events were suspected clinically (88%) or detected by imaging (9%). RBT results were frequently abnormal in asymptomatic patients (19%), with abnormal results leading to either additional investigations or an increased surveillance frequency in 8% of cases. The overall sensitivity and positive predictive value of abnormal RBT results in detecting progression events were 39% and 9%, respectively. CONCLUSION: RBTs have poor performance characteristics and rarely detect clinically significant disease progression or relapse in asymptomatic patients with iNHL.

SARS-CoV-2-Specific T Cells Exhibit Phenotypic Features of Helper Function, Lack of Terminal Differentiation, and High Proliferation Potential.

Convalescing coronavirus disease 2019 (COVID-19) patients mount robust T cell responses against SARS-CoV-2, suggesting an important role of T cells in viral clearance. To date, the phenotypes of SARS-CoV-2-specific T cells remain poorly defined. Using 38-parameter CyTOF, we phenotyped longitudinal specimens of SARS-CoV-2-specific CD4+ and CD8+ T cells from nine individuals who recovered from mild COVID-19. SARS-CoV-2-specific CD4+ T cells were exclusively Th1 cells and predominantly Tcm cells with phenotypic features of robust helper function. SARS-CoV-2-specific CD8+ T cells were predominantly Temra cells in a state of less terminal differentiation than most Temra cells. Subsets of SARS-CoV-2-specific T cells express CD127, can proliferate homeostatically, and can persist for over 2 months. Our results suggest that long-lived and robust T cell immunity is generated following natural SARS-CoV-2 infection and support an important role of SARS-CoV-2-specific T cells in host control of COVID-19.