Integrin αVß6 - autoantigen and driver of epithelial remodeling in colon and bile ducts in primary sclerosing cholangitis and inflammatory bowel disease.

Objective: Recently, autoantibodies directed against the epithelial adhesion protein integrin αVβ6 have been identified which strongly associate with ulcerative colitis (UC). We aimed to elucidate whether anti-integrin αVβ6 (anti- αVβ6) is present in primary sclerosing cholangitis (PSC), its associated inflammatory bowel disease or other cholestatic liver diseases and their persistence after proctocolectomy.

Design: We detected anti- αVβ6 by an enzyme-linked immunosorbent assay in sera collected at two German tertiary centers, including healthy controls (N=62), UC (N=36), Crohn's disease (CD, N=65), PSC-IBD (78 samples from N=41 patients), PSC without IBD (PSC, 41 samples from N=18 patients), primary biliary cholangitis (PBC, N=24), autoimmune hepatitis (AIH, N=32), secondary sclerosing cholangitis (SSC, N=12) and metabolic dysfunction-associated steatotic liver disease (MASLD, N=24).

Protective effect of the novel calcineurin inhibitor voclosporin in experimental colitis.

Background And Aims: Acute severe steroid-refractory ulcerative colitis remains a medically challenging condition with frequent need of surgery. It can be treated with the calcineurin inhibitor cyclosporine A with the need for therapeutic drug monitoring and significant toxicity. Recently, a novel calcineurin inhibitor, voclosporin, has been approved for the treatment of lupus nephritis with no need for therapeutic drug monitoring and an improved long-term safety profile.

Neutrophils prevent rectal bleeding in ulcerative colitis by peptidyl-arginine deiminase-4-dependent immunothrombosis.

Objective: Bleeding ulcers and erosions are hallmarks of active ulcerative colitis (UC). However, the mechanisms controlling bleeding and mucosal haemostasis remain elusive.

Design: We used high-resolution endoscopy and colon tissue samples of active UC (n = 36) as well as experimental models of physical and chemical mucosal damage in mice deficient for peptidyl-arginine deiminase-4 (PAD4), gnotobiotic mice and controls.

IgA2 Antibodies against SARS-CoV-2 Correlate with NET Formation and Fatal Outcome in Severely Diseased COVID-19 Patients.

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to an adaptive immune response in the host and the formation of anti-SARS-CoV-2 specific antibodies. While IgG responses against SARS-CoV-2 have been characterized quite well, less is known about IgA. IgA2 activates immune cells and induces inflammation and neutrophil extracellular trap (NET) formation which may contribute to organ injury and fatal outcome in SARS-CoV-2-infected patients.

Vascular occlusion by neutrophil extracellular traps in COVID-19.

Background: Coronavirus induced disease 2019 (COVID-19) can be complicated by severe organ damage leading to dysfunction of the lungs and other organs. The processes that trigger organ damage in COVID-19 are incompletely understood.

Methods: Samples were donated from hospitalized patients.

Citrullination Licenses Calpain to Decondense Nuclei in Neutrophil Extracellular Trap Formation.

Neutrophils respond to various stimuli by decondensing and releasing nuclear chromatin characterized by citrullinated histones as neutrophil extracellular traps (NETs). This achieves pathogen immobilization or initiation of thrombosis, yet the molecular mechanisms of NET formation remain elusive. Peptidyl arginine deiminase-4 (PAD4) achieves protein citrullination and has been intricately linked to NET formation.