Lung manifestations in MPO-ANCA associated vasculitides in children

IFN-γ promotes PANoptosis in Pasteurella multocida toxin-induced pneumonia in mice

Interferon-γ (IFN-γ) is a pleiotropic cytokine that regulates diverse biological functions, including modulation of inflammatory response and innate and adaptive immunity. In our study, we found that IFN-γ plays an important role in the regulation of Pasteurella multocida toxin-associated pneumonia. In work described here, we demonstrated that rPMT induced a lethal pneumonia in WT mice and the severity of the pneumonia was substantially alleviated in IFN-γ-deficient mice, IFN-γ deficiency significantly elevated the survival rate and reduced the pathological lesions of the lungs after rPMT challenged. Notably, IFN-γ deficiency significantly decreased myeloperoxidase (MPO) expression abundance in the lung tissue, and the MPO was mainly expressed in the lung tissue injury region of WT mice. More importantly, IFN-γ deficiency impaired the activation of PANoptosis specific markers, including the caspase 3, GSDMD, and MLKL, and reduced the expression of IL-1β. Cumulatively, this study demonstrates that IFN-γ promotes PANoptosis in PMT induced pneumonia in mice, providing a basis for studying the pathogenic mechanism of PMT.

Extracorporeal Membrane Oxygenation Support for Antineutrophil Cytoplasmic Antibody-associated Vasculitides: An ELSO Registry Analysis

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides with pulmonary involvement include granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis, and can present with life-threatening pulmonary hemorrhage in up to 40% of patients. Mortality in those patients who require intubation and mechanical ventilation can reach 77%. Extracorporeal membrane oxygenation (ECMO) can be used to support these patients through definitive diagnosis and treatment, although minimizing the risk of ventilator-induced lung injury. We aimed to determine factors associated with favorable outcomes in patients with (ANCA)-associated vasculitides supported on ECMO. We performed a retrospective observational study using the Extracorporeal Life Support Organization registry of pediatric and adult patients with ANCA-associated vasculitis supported on ECMO from 2010 to 2020. One hundred thirty-five patients were included for analysis. Many patients had renal involvement (39%) in addition to pulmonary involvement (93%). Survival was 73% in AAV patients supported on ECMO. The presence of pulmonary hemorrhage was not associated with worse outcomes in our cohort. Older age, the use of venoarterial ECMO, ECMO-cardiopulmonary resuscitation, or sustaining a cardiac arrest before ECMO was associated with decreased survival. In conclusion, venovenous ECMO should be considered as a supportive bridge to definitive diagnosis and treatment in (ANCA)-associated vasculitides, regardless if pulmonary hemorrhage is present.

Pulmonary manifestations and outcomes in paediatric ANCA-associated vasculitis: a single-centre experience

OBJECTIVES

ANCA-associated vasculitis (AAV) usually involves the renal and respiratory systems, but the paediatric literature on pulmonary manifestations and outcomes is limited. We aimed to describe pulmonary manifestations and outcomes after therapy in a cohort of paediatric AAV (pAAV) patients.

METHODS

A retrospective chart review of all patients <19 years presenting to our institution with AAV between 1/2008 and 2/2018 was conducted. Patient demographics, clinical presentation, diagnostic testing, therapy and pulmonary outcomes over the first 3 years after presentation were evaluated.

RESULTS

A total of 38 patients were included; all had ANCA positivity by immunofluorescence. A total of 23 had microscopic polyangiitis (MPA), 13 had granulomatosis with polyangiitis and 2 had eosinophilic granulomatosis with polyangiitis. A total of 30 (79%) had pulmonary manifestations, with cough (73%) and pulmonary haemorrhage (67%) being the most common. Abnormalities were noted in 82% of chest CT scans reviewed, with nodules and ground-glass opacities being the most common. At 6, 12 and 36 months follow-up, respectively, 61.8%, 39.4% and 29% of patients continued to show pulmonary manifestations. Five MPA patients with re-haemorrhage are described in detail.

CONCLUSION

MPA was more common than granulomatosis with polyangiitis, with pulmonary involvement being common in both. MPA patients had more severe pulmonary manifestations. Chest CT revealed abnormal findings in a majority of cases. A subgroup of young MPA patients experienced repeat pulmonary haemorrhage. Treatment modality and response were comparable in different subtypes of AAV, except for this young MPA group. Additional prospective studies are needed to better understand the different phenotypes of pAAV.

Pulmonary Manifestations of Systemic Vasculitis in Children

Vasculitides are defined according to the vessel size involved, and they tend to affect certain organ systems. Pulmonary involvement is rare in the common childhood vasculitides, such as Kawasaki disease, IgA vasculitis (Henoch Schonlein purpura). On the other hand, lung involvement is common in a rare pediatric vasculitis, granulomatosis with polyangiitis (GPA) (Wegener granulomatosis), where respiratory system findings are common. A criterion in the Ankara 2008 classification criteria for GPA is the presence of nodules, cavities, or fixed infiltrates. The adult data suggest that rituximab may be an alternative to cyclophosphamide in induction treatment.

European consensus-based recommendations for the diagnosis and treatment of rare paediatric vasculitides - the SHARE initiative

OBJECTIVES

The European initiative Single Hub and Access point for paediatric Rheumatology in Europe (SHARE) aimed to optimize care for children with rheumatic diseases. Systemic vasculitides are very rare in children. Consequently, despite recent advances, paediatric-specific information is sparse. The lack of evidence-based recommendations is an important, unmet need. This study aimed to provide recommendations for diagnosing and treating children with rare forms of childhood systemic vasculitis.

METHODS

Recommendations were developed by a consensus process in accordance with the European League Against Rheumatism standard operating procedures. A systematic literature review informed the recommendations, which were devised and evaluated by a panel of experts via an online survey, and two consensus meetings using nominal group technique. Recommendations were accepted when ⩾ 80% of experts agreed.

RESULTS

Ninety-three relevant articles were found, and 78 recommendations were accepted in the two consensus meetings. General, cross-cutting recommendations and disease-specific statements regarding the diagnosis and treatment of childhood-onset PAN, granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, and Takayasu arteritis are provided.

CONCLUSION

These Single Hub and Access point for paediatric Rheumatology in Europe recommendations were formulated through an evidence-based consensus process to support uniform, high-quality standard of care for children with rare forms of paediatric systemic vasculitis.

Milk fat globule-EGF factor 8 suppresses the aberrant immune response of systemic lupus erythematosus-derived neutrophils and associated tissue damage

Abnormal features of the systemic lupus erythematosus (SLE)-derived neutrophils, promoted aberrant immune response, have inspired new studies of the induction of autoimmunity and the development of organ damage in SLE. In this study, we explore the effect of milk fat globule-EGF factor 8 (MFG-E8) on the aberrant nitrification features in pristane-induced lupus. SLE patients and mice with pristane-induced lupus develop autoantibodies associated with MFG-E8 overproduction. However, the deletion of MFG-E8 leads to uncontrolled early pulmonary and peritoneal inflammation and tissue damage in mice with pristane-induced lupus. Consistent with these findings, MFG-E8-deficient mice that are exposed to pristane show enhanced neutrophil accumulation and increased neutrophil death, including apoptosis, necrosis and NETosis, as well as impaired phagocytosis of macrophages. The consequences are the expansion of diffuse pulmonary hemorrhage, increased anti-nuclear antibody, anti-dsDNA antibody and anti-neutrophil cytoplasmic antibody levels, and enhanced immune complexes deposition and neutrophil extracellular traps (NETs) formation in the lung and kidney tissues of MFG-E8-deficient mice exposed to pristane. In patients with SLE and mice with pristane-induced lupus, neutrophil accumulation is elevated, which depends on higher expression of the surface receptor CXCR2. After pretreatment with recombinant MFG-E8, the surface expression of CXCR2 on neutrophil is downregulated, and the MFG-E8 deletion increase CXCR2 expression by ~40%. These studies indicate that MFG-E8 reduces neutrophil migration and NETosis via downregulating surface CXCR2 expression in parallel with its role in the phagocytosis of apoptotic neutrophils, suggesting that MFG-E8 may serve as a therapeutic agent for attenuating the early inflammatory responses of SLE and protect patients from lupus-related damage.

Pulmonary vasculitis

Pulmonary vasculitis encompasses inflammation in the pulmonary vasculature with involved vessels varying in caliber from large elastic arteries to capillaries. Small pulmonary capillaries are the vessels most commonly involved in vasculitis affecting the lung. The antineutrophil cytoplasmic antibody-associated vasculitides, which include granulomatosis with polyangiitis (formerly Wegener granulomatosis), microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome), are the small vessel vasculitides in which pulmonary vasculitis is most frequently observed and are the major focus of this review. Vasculitic involvement of the large pulmonary vessels as may occur in Behçet syndrome and Takayasu arteritis is also discussed.