Increase in the number of new cases of ANCA-associated vasculitis in the COVID-19 vaccine era.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune vasculitis characterized by the production of antibodies against ANCA, with unclear pathogenesis. With the ongoing COVID-19 pandemic, COVID-19 mRNA vaccination has been available in Japan since February 2021. Although autoimmune symptoms have been reported after COVID-19 vaccinations, there have been no clinical investigations regarding the relationship between COVID-19 mRNA vaccines and the pathogenesis of AAV. Thus, the present study aimed to investigate whether the administration of COVID-19 mRNA vaccines affects the development of AAV. The study identified patients with new-onset AAV who were MPO-ANCA or PR3-ANCA positive and met the entry criteria of the AAV EMA classification algorithm. The study compared the number of new AAV cases per year before and after the start of the COVID-19 mRNA vaccine program in Japan. The study found that the annual number of new cases of AAV in Japan's Nagasaki Prefecture increased by approximately 1.5-fold since the COVID-19 vaccine program was initiated, suggesting a possible link between the COVID-19 mRNA vaccines and the development of AAV. Although the study provides insight into the clinical evaluation and management of autoimmune symptoms following COVID-19 vaccination, further investigation of the possible association between COVID-19 mRNA vaccines and the pathogenesis of AAV is required.

Score to assess the probability of relapse in granulomatosis with polyangiitis and microscopic polyangiitis.

OBJECTIVE: To develop a score assessing the probability of relapse in granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). METHODS: Long-term follow-up data from GPA and MPA patients included in five consecutive randomised controlled trials were pooled. Patient characteristics at diagnosis were entered into a competing-risks model, with relapse as the event of interest and death the competing event. Univariate and multivariate analyses were computed to identify variables associated with relapse and build a score, which was then validated in an independent cohort of GPA or MPA patients. RESULTS: Data collected from 427 patients (203 GPA, 224 MPA) at diagnosis were included. Mean±SD follow-up was 80.6±51.3 months; 207 (48.5%) patients experienced ≥1 relapse. Relapse risk was associated with proteinase 3 (PR3) positivity (HR=1.81 (95% CI 1.28 to 2.57); p<0.001), age ≤75 years (HR=1.89 (95% CI 1.15 to 3.13); p=0.012) and estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m² (HR=1.67 (95% CI 1.18 to 2.33); p=0.004) at diagnosis. A score, the French Vasculitis Study Group Relapse Score (FRS), from 0 to 3 points was modelised: 1 point each for PR3-antineutrophil cytoplasmic antibody positivity, eGFR ≥30 mL/min/1.73 m² and age ≤75 years. In the validation cohort of 209 patients, the 5-year relapse risk was 8% for a FRS of 0, 30% for 1, 48% for 2 and 76% for 3. CONCLUSION: The FRS can be used at diagnosis to assess the relapse risk in patients with GPA or MPA. Its value for tailoring the duration of maintenance therapy should be evaluated in future prospective trials.

Hepatic and pulmonary involvement in a patient with PR3-ANCA vasculitis following SARS-CoV-2 vaccination: A case report.

We here report the first case of anti-proteinase 3-positive anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis following the severe acute respiratory syndrome coronavirus 2 Pfizer-BioNTech vaccine presenting with prominent liver involvement and alveolar haemorrhage. Two weeks after vaccination, a 49-year-old man developed inflammatory arthralgias and hypertransaminasaemia. Two months later, fever and haemoptysis appeared; the patient tested positive for anti-proteinase 3 autoantibodies. High-dose steroids and rituximab were started, and complete remission was achieved. Systemic autoimmune diseases, including ANCA-associated vasculitis, should always be considered in the differential diagnosis of hypertransaminasaemia, especially when the clinical context is suspicious.

Soluble Signal Inhibitory Receptor on Leukocytes-1 Is Released from Activated Neutrophils by Proteinase 3 Cleavage.

Signal inhibitory receptor on leukocytes-1 (SIRL-1) is an immune inhibitory receptor expressed on human granulocytes and monocytes that dampens antimicrobial functions. We previously showed that sputum neutrophils from infants with severe respiratory syncytial virus (RSV) bronchiolitis have decreased SIRL-1 surface expression compared with blood neutrophils and that SIRL-1 surface expression is rapidly lost from in vitro activated neutrophils. This led us to hypothesize that activated neutrophils lose SIRL-1 by ectodomain shedding. Here, we developed an ELISA and measured the concentration of soluble SIRL-1 (sSIRL-1) in patients with RSV bronchiolitis and hospitalized patients with COVID-19, which are both characterized by neutrophilic inflammation. In line with our hypothesis, sSIRL-1 concentration was increased in sputum compared with plasma of patients with RSV bronchiolitis and in serum of hospitalized patients with COVID-19 compared with control serum. In addition, we show that in vitro activated neutrophils release sSIRL-1 by proteolytic cleavage and that this diminishes the ability to inhibit neutrophilic reactive oxygen species production via SIRL-1. Finally, we found that SIRL-1 shedding is prevented by proteinase 3 inhibition and by extracellular adherence protein from Staphylococcus aureus. Notably, we recently showed that SIRL-1 is activated by PSMα3 from S. aureus, suggesting that S. aureus may counteract SIRL-1 shedding to benefit from preserved inhibitory function of SIRL-1. In conclusion, we report that SIRL-1 is released from activated neutrophils by proteinase 3 cleavage and that endogenous sSIRL-1 protein is present in vivo.

Targeting Cathepsin C in PR3-ANCA Vasculitis.

BACKGROUND: The ANCA autoantigens proteinase 3 (PR3) and myeloperoxidase (MPO) are exclusively expressed by neutrophils and monocytes. ANCA-mediated activation of these cells is the key driver of the vascular injury process in ANCA-associated vasculitis (AAV), and neutrophil serine proteases (NSPs) are disease mediators. Cathepsin C (CatC) from zymogens activates the proteolytic function of NSPs, including PR3. Lack of NSP zymogen activation results in neutrophils with strongly reduced NSP proteins. METHODS: To explore AAV-relevant consequences of blocking NSP zymogen activation by CatC, we used myeloid cells from patients with Papillon-Lefèvre syndrome, a genetic deficiency of CatC, to assess NSPs and NSP-mediated endothelial cell injury. We also examined pharmacologic CatC inhibition in neutrophil-differentiated human hematopoietic stem cells, primary human umbilical vein cells, and primary glomerular microvascular endothelial cells. RESULTS: Patients with Papillon-Lefèvre syndrome showed strongly reduced NSPs in neutrophils and monocytes. Neutrophils from these patients produced a negative PR3-ANCA test, presented less PR3 on the surface of viable and apoptotic cells, and caused significantly less damage in human umbilical vein cells. These findings were recapitulated in human stem cells, in which a highly specific CatC inhibitor, but not prednisolone, reduced NSPs without affecting neutrophil differentiation, reduced membrane PR3, and diminished neutrophil activation upon PR3-ANCA but not MPO-ANCA stimulation. Compared with healthy controls, neutrophils from patients with Papillon-Lefèvre syndrome transferred less proteolytically active NSPs to glomerular microvascular endothelial cells, the cell type targeted in ANCA-induced necrotizing crescentic glomerulonephritis. Finally, both genetic CatC deficiency and pharmacologic inhibition, but not prednisolone, reduced neutrophil-induced glomerular microvascular endothelial cell damage. CONCLUSIONS: These findings may offer encouragement for clinical studies of adjunctive CatC inhibitor in patients with PR3-AAV.

Variation of Proteolytic Cleavage Sites towards the N-Terminal End of the S2 Subunit of the Novel SARS-CoV-2 Omicron Sublineage BA.2.12.1.

The prevalence of novel SARS-CoV-2 variants is also accompanied by an increased turnover rate and additional cleavage sites at the positions necessary for priming the Spike (S) protein. Of these priming sites, the proteolytically sensitive polybasic sequence of the activation loop at the S1/S2 interface and the S2' location within the S2 subunit of the S protein are cleaved by furin and TMPRSS2, which are important for the infection of the target cell. Neutrophils, migrating to the site of infection, secrete serine proteases to fight against pathogens. The serine proteases encompass neutrophil elastase (NE), proteinase 3 (PR3), and cathepsin G (CatG), which can hydrolyze the peptide bond adjacent to the S1/S2 interface. SARS-CoV-2 might take the opportunity to hijack proteases from an immune response to support viral entry to the cell. The region near S704L within the S2 subunit, a novel amino acid substitution of SARS-CoV-2 Omicron sublineage BA.2.12.1, is located close to the S1/S2 interface. We found that NE, PR3, and CatG digested the peptide within this region; however, the S704L amino acid substitution altered cleavage sites for PR3. In conclusion, such an amino acid substitution modifies S2 antigen processing and might further impact the major histocompatibility complex (MHC) binding and T cell activation.

Enhanced Expression of Autoantigens During SARS-CoV-2 Viral Infection.

Immune homeostasis is disturbed during severe viral infections, which can lead to loss of tolerance to self-peptides and result in short- or long-term autoimmunity. Using publicly available transcriptomic datasets, we conducted an in-silico analyses to evaluate the expression levels of 52 autoantigens, known to be associated with 24 autoimmune diseases, during SAR-CoV-2 infection. Seven autoantigens (MPO, PRTN3, PADI4, IFIH1, TRIM21, PTPRN2, and TSHR) were upregulated in whole blood samples. MPO and TSHR were overexpressed in both lung autopsies and whole blood tissue and were associated with more severe COVID-19. Neutrophil activation derived autoantigens (MPO, PRTN3, and PADI4) were prominently increased in blood of both SARS-CoV-1 and SARS-CoV-2 viral infections, while TSHR and PTPRN2 autoantigens were specifically increased in SARS-CoV-2. Using single-cell dataset from peripheral blood mononuclear cells (PBMCs), we observed an upregulation of MPO, PRTN3, and PADI4 autoantigens within the low-density neutrophil subset. To validate our in-silico analysis, we measured plasma protein levels of two autoantigens, MPO and PRTN3, in severe and asymptomatic COVID-19. The protein levels of these two autoantigens were significantly upregulated in more severe COVID-19 infections. In conclusion, the immunopathology and severity of COVID-19 could result in transient autoimmune activation. Longitudinal follow-up studies of confirmed cases of COVID-19 could determine the enduring effects of viral infection including development of autoimmune disease.

The Inflammatory Factors Associated with Disease Severity to Predict COVID-19 Progression.

Coronavirus disease 2019 (COVID-19) is associated with immune dysregulation and cytokine storm. Exploring the immune-inflammatory characteristics of COVID-19 patients is essential to reveal pathogenesis and predict progression. In this study, COVID-19 patients showed decreased CD3+, CD4+, and CD8+ T cells but increased neutrophils in circulation, exhibiting upregulated neutrophil-to-lymphocyte and neutrophil-to-CD8+ T cell ratio. IL-6, TNF-α, IL-1ß, IL-18, IL-12/IL-23p40, IL-10, Tim-3, IL-8, neutrophil extracellular trap-related proteinase 3, and S100A8/A9 were elevated, whereas IFN-γ and C-type lectin domain family 9 member A (clec9A) were decreased in COVID-19 patients compared with healthy controls. When compared with influenza patients, the expressions of TNF-α, IL-18, IL-12/IL-23p40, IL-8, S100A8/A9 and Tim-3 were significantly increased in critical COVID-19 patients, and carcinoembryonic Ag, IL-8, and S100A8/A9 could serve as clinically available hematologic indexes for identifying COVID-19 from influenza. Moreover, IL-6, IL-8, IL-1ß, TNF-α, proteinase 3, and S100A8/A9 were increased in bronchoalveolar lavage fluid of severe/critical patients compared with moderate patients, despite decreased CD4+ T cells, CD8+ T cells, B cells, and NK cells. Interestingly, bronchoalveolar IL-6, carcinoembryonic Ag, IL-8, S100A8/A9, and proteinase 3 were found to be predictive of COVID-19 severity and may serve as potential biomarkers for predicting COVID-19 progression and potential targets in therapeutic intervention of COVID-19.