[COVID-19 development during the treatment of paroxysmal nocturnal hemoglobinuria].

Paroxysmal nocturnal hemoglobinuria (PNH) is a disorder in which an activated complement causes intravascular hemolysis of erythrocytes that do not have complement regulators. It is critical to monitor the rapid progression of hemolysis caused by infection and thrombosis. As far as we can tell, this is the first report of 5 COVID-19 patients with PNH in Japan. Three patients were being treated with ravulizumab, one with eculizumab, and one with crovalimab. All five cases had received two or more COVID-19 vaccinations. COVID-19 was classified as mild in four cases and moderate in one. None of the cases required the use of oxygen, and none became severe. All of them experienced breakthrough hemolysis, and two required red blood cell transfusions. In any case, no thrombotic complications were observed.