High activation levels maintained in receptor-binding domain-specific memory B cells in people with severe coronavirus disease 2019.

The long-term health consequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are still being understood. The molecular and phenotypic properties of SARS-CoV-2 antigen-specific T cells suggest a dysfunctional profile that persists in convalescence in those who were severely ill. By contrast, the antigen-specific memory B-cell (MBC) population has not yet been analyzed to the same degree, but phenotypic analysis suggests differences following recovery from mild or severe coronavirus disease 2019 (COVID-19). Here, we performed single-cell molecular analysis of the SARS-CoV-2 receptor-binding domain (RBD)-specific MBC population in three patients after severe COVID-19 and four patients after mild/moderate COVID-19. We analyzed the transcriptomic and B-cell receptor repertoire profiles at ~2 months and ~4 months after symptom onset. Transcriptomic analysis revealed a higher level of tumor necrosis factor-alpha (TNF-α) signaling via nuclear factor-kappa B in the severe group, involving CD80, FOS, CD83 and TNFAIP3 genes that was maintained over time. We demonstrated the presence of two distinct activated MBCs subsets based on expression of CD80hi TNFAIP3hi and CD11chi CD95hi at the transcriptome level. Both groups revealed an increase in somatic hypermutation over time, indicating progressive evolution of humoral memory. This study revealed distinct molecular signatures of long-term RBD-specific MBCs in convalescence, indicating that the longevity of these cells may differ depending on acute COVID-19 severity.

Interferon-λ3 Exacerbates the Inflammatory Response to Microbial Ligands: Implications for SARS-CoV-2 Pathogenesis.

INTRODUCTION: Interferon lambdas (IFN-λs) are antiviral cytokines that restrict pathogen infection and dissemination at barrier surfaces. Controlled expression of IFN-λs efficiently eliminates acute infections by activating a suite of interferon stimulated genes that inhibit viral propagation and activate local immune cells. Excessive or prolonged production of IFN-λs can however mediate tissue inflammation and disrupt epithelial barriers in both viral and non-viral disease. The mechanism by which IFN-λs drive this disease pathogenesis is poorly understood but may be caused by IFN-λ-mediated amplification of other innate immune signaling pathways. METHODS: Monocyte-derived macrophages were differentiated ± IFN-λ3 and treated with KDO-lipid A, poly I:C or zymosan, representing bacterial, viral or fungal ligands, respectively. Transcriptome and protein expression were quantified by RNA sequencing/PCR and ELISA/bead array, respectively. Bioinformatic analysis was used to define transcription factor profiles and signaling pathways amplified by IFN-λ3. Finally, the SARS-CoV-2 dataset GSE152075 was queried to compare the effects of IFNL versus IFNA expression in relation to viral load and nasopharyngeal transcriptomes. RESULTS: IFN-λ3 exacerbated inflammatory and chemotactic responses unique to each microbial ligand, as measured by RNA sequencing and by ELISA/bead array. Functional annotation identified pathways amplified by IFN-λ3, including inflammasome activation. Inflammasome amplification was confirmed in vitro, as measured by caspase 1 activity and IL-1ß cleavage. Lastly, SARS-CoV-2 infected nasopharyngeal transcriptomes expressing IFN-λs but not IFN-αs were implicated in myeloid cell-driven pathogenesis including neutrophil degranulation, complement and coagulation cascades. DISCUSSION: These data suggest that IFN-λs contribute to disease pathology by exacerbating innate immune responses during chronic or severe disease states. IFN-λs may contribute to SARS-CoV-2 disease severity, however further study is required to confirm true causation.

Depression, anxiety and stress among patients with inflammatory bowel disease during the COVID-19 pandemic: Australian national survey.

BACKGROUND: The global COVID-19 pandemic has impacted on the mental health of individuals, particularly those with chronic illnesses. We aimed to quantify stress, anxiety and depression among individuals with Inflammatory bowel disease (IBD) in Australia during the pandemic. METHODS: An electronic survey was made available to IBD patients Australia-wide from 17 June to 12 July 2020. Respondents with an underlying diagnosis of IBD and over 18 years of age were included. A validated questionnaire (Depression, Anxiety, Stress Score-21, DASS21) was used to assess depression, anxiety and stress. Data on potential predictors of depression, anxiety and stress were collected. RESULTS: 352 participated in the survey across Australia. 60.5% of respondents fulfilled DASS criteria for at least moderate depression, anxiety or stress. 45% reported a pre-existing diagnosis of depression and/or anxiety. Over 2/3 of these respondents reported worsening of their pre-existing depression/anxiety due to the current pandemic. Of those without a pre-existing diagnosis of anxiety or depression, high rates of at least moderate to severe depression (34.9%), anxiety (32.0%) and stress (29.7%) were noted. Younger age (OR 0.96, 95% CI 0.94 to 0.98, p<0.001), lack of access to an IBD nurse (OR 1.81, 95% CI 1.03 to 3.19, p=0.04) and lack of education on reducing infection risk (OR 1.99, 95% CI 1.13 to 3.50, p=0.017) were associated with significant stress, anxiety and/or depression. CONCLUSION: High prevalence of undiagnosed depression, anxiety and stress was identified among respondents. Improved access to IBD nurse support and greater attention to education are modifiable factors that may reduce depression, anxiety and/or stress among patients with IBD during the pandemic.