Background Perinuclear anti‐neutrophil cytoplasmic antibodies (P‐ANCA) are associated with a multisystem vasculitis affecting small blood vessels in the body. A handful of adult patients who developed vasculitis post‐COVID‐19 have been reported. Although SARS‐CoV‐2 has been shown to drive an exaggerated immune response in the pediatric population, such as in Multisystem Inflammatory Syndrome in Children (MIS‐C), only one case of vasculitis following COVID‐19 has been reported previously in children. Case presentation Seventeen‐year‐old male with a past medical history of COVID‐19 pneumonia two months prior presented with acute kidney injury and diffuse alveolar hemorrhage. Rheumatologic workup revealed P‐ANCA and Myeloperoxidase (MPO) positivity. Kidney biopsy showed necrotizing glomerulonephritis with limited immune complex deposition. Subsequently, he was treated with steroids and plasmapheresis, and ultimately started on cyclophosphamide. Conclusions To our knowledge, this report presents the second reported pediatric case of P‐ANCA/MPO vasculitis following COVID‐19.

Background: Perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCA), a subset of ANCA, are associated with a multisystem vasculitis affecting small blood vessels in the body. A handful of adult patients who developed vasculitis post-COVID-19 infection have been reported. Although COVID-19 infection has been shown to drive an exaggerated immune response in the pediatric population, such as MIS-C (multisystem inflammatory syndrome in children), only one case of vasculitis following COVID-19 infection has been reported previously in children. Case presentation: Seventeen-year-old male with a past medical history of COVID-19 pneumonia two months prior presented with acute kidney injury/failure and diffuse alveolar hemorrhage (DAH). Rheumatologic workup revealed P-ANCA and Myeloperoxidase (MPO) positivity. Kidney biopsy showed necrotizing glomerulonephritis with limited immune complex deposition. Subsequently, he was treated with pulse steroids, plasmapheresis, and ultimately started on cyclophosphamide. Conclusions: To our knowledge, this report presents the second reported pediatric case of P-ANCA / MPO vasculitis following COVID-19 infection.

Human epithelial cell lines were utilized to examine the effects of anoxia on cellular growth and metabolism. Three normal human epithelial cells lines (A549, NHBE, and BEAS-2B) as well as a cystic fibrosis cell line (IB3-1) and its mutation corrected cell line (C38) were grown in the presence and absence of oxygen for varying periods of time. Interleukin-8 (IL-8) levels were measured by enzyme-linked immunosorbent assay technique. Cellular metabolism and proliferation were assayed by determining mitochondrial oxidative burst activity by tetrazolium compound reduction. The viability of cells was indirectly measured by lactate dehydrogenase release. A549, NHBE, and BEAS-2B cells cultured in the absence of oxygen showed a progressive decrease in metabolic activity and cell proliferation after one to three days. There was a concomitant increase in IL-8 production. Cell lines from cystic fibrosis (CF) patients did not show a similar detrimental effect of anoxia. However, the IL-8 level was significantly increased only in IB3-1 cells exposed to anoxia after two days. Anoxia appears to affect certain airway epithelial cell lines uniquely with decreased cellular proliferation and a concomitant increased production of a cytokine with neutrophilic chemotactic activity. The increased ability of the CF cell line to respond to anoxia with increased secretion of inflammatory cytokines may contribute to the inflammatory damage seen in CF bronchial airway. This study indicates the need to use different cell lines in in vitro studies investigating the role of epithelial cells in airway inflammation and the effects of environmental influences.