Memory T cells effectively recognize the SARS-CoV-2 hypermutated BA.2.86 variant.

T cells are critical in mediating the early control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection. However, it remains unknown whether memory T cells can effectively cross-recognize new SARS-CoV-2 variants with a broad array of mutations, such as the emergent hypermutated BA.2.86 variant. Here, we report in two separate cohorts, including healthy controls and individuals with chronic lymphocytic leukemia, that SARS-CoV-2 spike-specific CD4+ and CD8+ T cells induced by prior infection or vaccination demonstrate resilient immune recognition of BA.2.86. In both cohorts, we found largely preserved SARS-CoV-2 spike-specific CD4+ and CD8+ T cell magnitudes against mutated spike epitopes of BA.2.86. Functional analysis confirmed that both cytokine expression and proliferative capacity of SARS-CoV-2 spike-specific T cells to BA.2.86-mutated spike epitopes are similarly sustained. In summary, our findings indicate that memory CD4+ and CD8+ T cells continue to provide cell-mediated immune recognition to highly mutated emerging variants such as BA.2.86.

Impact of the gut microbiome on immunological responses to COVID-19 vaccination in healthy controls and people living with HIV.

Although mRNA SARS-CoV-2 vaccines are generally safe and effective, in certain immunocompromised individuals they can elicit poor immunogenic responses. Among these individuals, people living with HIV (PLWH) have poor immunogenicity to several oral and parenteral vaccines. As the gut microbiome is known to affect vaccine immunogenicity, we investigated whether baseline gut microbiota predicts immune responses to the BNT162b2 mRNA SARS-CoV-2 vaccine in healthy controls and PLWH after two doses of BNT162b2. Individuals with high spike IgG titers and high spike-specific CD4+ T-cell responses against SARS-CoV-2 showed low α-diversity in the gut. Here, we investigated and presented initial evidence that the gut microbial composition influences the response to BNT162b2 in PLWH. From our predictive models, Bifidobacterium and Faecalibacterium appeared to be microbial markers of individuals with higher spike IgG titers, while Cloacibacillus was associated with low spike IgG titers. We therefore propose that microbiome modulation could optimize immunogenicity of SARS-CoV-2 mRNA vaccines.

Poor dental health and risk of pancreatic cancer: a nationwide registry-based cohort study in Sweden, 2009-2016.

BACKGROUND: Previous studies have reported inconsistent results regarding the association between poor dental health and pancreatic cancer risk. This study aimed to assess this association using a well-functioning nationwide dental health registry in Sweden. METHODS: Information of exposures (dental caries, root canal infection, mild inflammation, and periodontitis; the number of teeth) was ascertained from the Swedish Dental Health Register, and occurrence of pancreatic cancer was identified from both cancer and cause of death registries. Hazard ratios (HRs) were estimated using Cox models. RESULTS: During a median of 7.2 years of follow-up, 10,081 pancreatic cancers were identified among 5,889,441 individuals. Compared with the healthy status, a higher risk of pancreatic cancer was observed in individuals with root canal infection, mild inflammation, and periodontitis in the <50 age group (P for trend <0.001). In the 50-70 age group, only the subgroup with periodontitis had an excess risk (multivariable-adjusted HR = 1.20, 95% confidence interval [CI] 1.11-1.29). No positive association with statistical significance was observed in the 70+ age group. Individuals with fewer teeth tended to have a higher risk in all age groups. CONCLUSIONS: Our results confirmed the association between poor dental health and pancreatic cancer risk, which warrants further studies on underlying mechanisms.

Preserved Mucosal-Associated Invariant T Cells in the Cervical Mucosa of HIV-Infected Women with Dominant Expression of the TRAV1-2-TRAJ20 T Cell Receptor α-Chain.

BACKGROUND: Mucosa-associated invariant T (MAIT) cells are innate-like T cells with specialized antimicrobial functions. Circulating MAIT cells are depleted in chronic human immunodeficiency virus (HIV) infection, but studies examining this effect in peripheral tissues, such as the female genital tract, are lacking. METHODS: Flow cytometry was used to investigate circulating MAIT cells in a cohort of HIV-seropositive (HIV+) and HIV-seronegative (HIV-) female sex workers (FSWs), and HIV- lower-risk women (LRW). In situ staining and quantitative polymerase chain reaction were performed to explore the phenotype of MAIT cells residing in paired cervicovaginal tissue. The cervicovaginal microbiome was assessed by means of 16S ribosomal RNA gene sequencing. RESULTS: MAIT cells in the HIV+ FSW group were low in frequency in the circulation but preserved in the ectocervix. MAIT cell T-cell receptor gene segment usage differed between the HIV+ and HIV- FSW groups. The TRAV1-2-TRAJ20 transcript was the most highly expressed MAIT TRAJ gene detected in the ectocervix in the HIV+ FSW group. MAIT TRAVJ usage was not associated with specific genera in the vaginal microbiome. CONCLUSIONS: MAIT cells residing in the ectocervix are numerically preserved irrespective of HIV infection status and displayed dominant expression of TRAV1-2-TRAJ20. These findings have implications for understanding the role of cervical MAIT cells in health and disease.

Evaluating the prevalence of Hepatitis E virus infection in a large cohort of European blood donors, 2015-2018.

Hepatitis E virus (HEV) is endemic in Europe. However, standardized methods for the surveillance of HEV viremia in the general population are lacking. This study aimed to compare the incidence of HEV among blood donors in two European countries, Germany and Portugal, during the period 2015-2018. The seasonal distribution of HEV infection, as well as host risk factors including age, sex, and blood group phenotype were explored. A total of 191,236 donations from Germany and Portugal were tested for HEV RNA in plasma mini-pools of up to 96 donations using an internally controlled reverse transcription real-time PCR (RT-PCR) assay. The 95% cut-off of the assay was 15 International Units (IU)/mL (CI 10-35 IU/mL) as determined by dilution of the WHO International Standard for HEV RNA. Blood type was determined by agglutination and pattern recognition using the Beckmann Coulter PK 7300 AB0- and Rhesus-Assay. The overall positivity rate was 0.09% with significantly more infections observed in the German cohort (p < 0.0001). Infections peaked in the summer months, and investigation of risk factors revealed that incidence was significantly higher amongst males (p = 0.0002), but was not associated with ABO or Rh(D) blood group phenotypes. No significant relationships between risk factors and viral load were observed. Our findings confirm that HEV infections are highly prevalent in Europe, even amongst otherwise healthy blood donors. Increasing awareness of the seasonal spread and risk factors for HEV transmission is of great importance for individuals susceptible to more severe forms of the disease, such as immunocompromised patients.

Safety and efficacy of the mRNA BNT162b2 vaccine against SARS-CoV-2 in five groups of immunocompromised patients and healthy controls in a prospective open-label clinical trial.

BACKGROUND: Patients with immunocompromised disorders have mainly been excluded from clinical trials of vaccination against COVID-19. Thus, the aim of this prospective clinical trial was to investigate safety and efficacy of BNT162b2 mRNA vaccination in five selected groups of immunocompromised patients and healthy controls. METHODS: 539 study subjects (449 patients and 90 controls) were included. The patients had either primary (n=90), or secondary immunodeficiency disorders due to human immunodeficiency virus infection (n=90), allogeneic hematopoietic stem cell transplantation/CAR T cell therapy (n=90), solid organ transplantation (SOT) (n=89), or chronic lymphocytic leukemia (CLL) (n=90). The primary endpoint was seroconversion rate two weeks after the second dose. The secondary endpoints were safety and documented SARS-CoV-2 infection. FINDINGS: Adverse events were generally mild, but one case of fatal suspected unexpected serious adverse reaction occurred. 72.2% of the immunocompromised patients seroconverted compared to 100% of the controls (p=0.004). Lowest seroconversion rates were found in the SOT (43.4%) and CLL (63.3%) patient groups with observed negative impact of treatment with mycophenolate mofetil and ibrutinib, respectively. INTERPRETATION: The results showed that the mRNA BNT162b2 vaccine was safe in immunocompromised patients. Rate of seroconversion was substantially lower than in healthy controls, with a wide range of rates and antibody titres among predefined patient groups and subgroups. This clinical trial highlights the need for additional vaccine doses in certain immunocompromised patient groups to improve immunity. FUNDING: Knut and Alice Wallenberg Foundation, the Swedish Research Council, Nordstjernan AB, Region Stockholm, Karolinska Institutet, and organizations for PID/CLL-patients in Sweden.

Isolation of pancreatic microbiota from cystic precursors of pancreatic cancer with intracellular growth and DNA damaging properties.

Emerging research suggests gut microbiome may play a role in pancreatic cancer initiation and progression, but cultivation of the cancer microbiome remains challenging. This pilot study aims to investigate the possibility to cultivate pancreatic microbiome from pancreatic cystic lesions associated with invasive cancer. Intra-operatively acquired pancreatic cyst fluid samples showed culture-positivity mainly in the intraductal papillary mucinous neoplasm (IPMN) group of lesions. MALDI-TOF MS profiling analysis shows Gammaproteobacteria and Bacilli dominate among individual bacteria isolates. Among cultivated bacteria, Gammaproteobacteria, particularly Klebsiella pneumoniae, but also Granulicatella adiacens and Enterococcus faecalis, demonstrate consistent pathogenic properties in pancreatic cell lines tested in ex vivo co-culture models. Pathogenic properties include intracellular survival capability, cell death induction, or causing DNA double-strand breaks in the surviving cells resembling genotoxic effects. This study provides new insights into the role of the pancreatic microbiota in the intriguing link between pancreatic cystic lesions and cancer.

Metabolic Characterization of Plasma and Cyst Fluid from Cystic Precursors to Pancreatic Cancer Patients Reveal Metabolic Signatures of Bacterial Infection.

Pancreatic cancer is the seventh leading cause of cancer-related death worldwide, with a 5 year survival rate as low as 9%. One factor complicating the management of pancreatic cancer is the lack of reliable tools for early diagnosis. While up to 50% of the adult population has been shown to develop precancerous pancreatic cysts, limited and insufficient approaches are currently available to determine whether a cyst is going to progress into pancreatic cancer. Recently, we used metabolomics approaches to identify candidate markers of disease progression in patients diagnosed with intraductal papillary mucinous neoplasms (IPMNs) undergoing pancreatic resection. Here, we enrolled an independent cohort to verify the candidate markers from our previous study with orthogonal quantitative methods in plasma and cyst fluid from serous cystic neoplasm and IPMN (either low- or high-grade dysplasia or pancreatic ductal adenocarcinoma). We thus validated these markers with absolute quantitative methods through the auxilium of stable isotope-labeled internal standards in a new independent cohort. Finally, we identified novel markers of IPMN status and disease progression-including amino acids, carboxylic acids, conjugated bile acids, free and carnitine-conjugated fatty acids, purine oxidation products, and trimethylamine-oxide. We show that the levels of these metabolites of potential bacterial origin correlated with the degree of bacterial enrichment in the cyst, as determined by 16S RNA. Overall, our findings are interesting per se, owing to the validation of previous markers and identification of novel small molecule signatures of IPMN and disease progression. In addition, our findings further fuel the provoking debate as to whether bacterial infections may represent an etiological contributor to the development and severity of the disease in pancreatic cancer, in like fashion to other cancers (e.g., Helicobacter pylori and gastric cancer).

A randomized controlled trial: the efficacy of eluoride rinse combined with calcium pre-rinse to increase overnight salivary fluoride.

BACKGROUND: Previous studies have shown that a calcium (Ca) pre-rinse given before a 228 ppm fluoride (F) rinse greatly increased salivary fluoride. Objectives. The aim of this randomized controlled trial is to examine if Ca pre-rinse could increase the fluoride concentration in the overnight unstimulated saliva after a 905 ppm F-rinse. MATERIALS AND METHODS: Pre-rinses containing 150 mM, 75 mM or 0 mM Ca-lactate prepared by a validated pharmaceutical cGPM procedure were tested by nine subjects in a randomized order immediately followed by a 905 ppm F-rinse. The fluoride concentration was measured in unstimulated saliva collected 10 h later. RESULTS AND CONCLUSIONS: The Ca pre-treatment significantly increased F level in overnight saliva following the 905 ppm fluoride rinse by 1.7× relative to the 905 ppm F-rinse alone; however, a significant effect was only observed with the highest (150 mM) Ca concentration as pre-rinse. Clinical relevance. High concentration F rinses (905 ppm) are commonly recommended for patients at high-risk of caries. A pre-treatment with high levels of Ca may further improve the cariostatic effect of this ion.