A case of C-ANCA-positive systematic lupus erythematous and ANCA-associated vasculitis overlap syndrome superimposed by COVID-19: a fatal trio.

Coronavirus disease 2019 (COVID-19) poses a substantial challenge for rheumatologists and rheumatologic patients. They are concerned about the reciprocal interaction between connective tissue diseases, such as systemic lupus erythematosus (SLE), and the virus. Here, we report a 21-year-old female SLE patient presented to the emergency department with gastrointestinal symptoms and kidney involvement evidence. Based on the pathology and laboratory assessments, she was suspected of C-antineutrophil cytoplasmic antibody (ANCA) positive SLE and ANCA-associated vasculitis overlap syndrome (SLE/AAV OS), and plasmapheresis was performed every other day due to this diagnosis alongside the high titer of C-ANCA. We also administered methylprednisolone [1 g/day, intravenous (IV)] for 3 days, followed by dexamethasone with the maintenance dosage (1 mg/kg/day, IV). Although the patient's general condition improved the next days, her condition deteriorated suddenly on the 7th day of hospitalisation. She got intubated and went to the intensive care unit. Despite taking possible measures to manage the patient's condition, she eventually passed away due to severe acute respiratory distress syndrome, triggered by COVID-19. The distinct role of C-ANCA in SLE/AAV vascular damage and activating neutrophil cytokine release accompanied by the impaired immune system while facing COVID-19 seems to lead to increased morbidity and mortality in such patients. This report is presented to bring into consideration the possible role of C-ANCA in the prognosis of COVID-19 in SLE/AAV OS patients.