Red blood cell morphology in patients with COVID-19-related anaemia

Abstract

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In patients with COVID-19 pneumonia, severe anaemia on hospital admission is uncommon1. However, haemoglobin (Hb) concentration tends to progressively decline during the course of the disease. Both sepsis and hypoxia have profound effects on red cell morphology, rheology and survival, likely contributing to the complex pathogenesis of COVID-19 anaemia. In this regard, during the peak of the COVID-19 outbreak in Northern Italy, we observed that 39% of the inpatients required transfusion support after a median of 15 days of hospitalisation. Red blood cell (RBC)-bound antibodies were detectable by direct antiglobulin test (DAT) in almost half of the patients with severe COVID-19, and their presence was associated with lower Hb levels and greater transfusion requirement2. In addition, we and others have recently demonstrated that the ABO blood group is one of the two loci associated with the susceptibility to develop COVID-19-induced respiratory failure with genome-wide significance. Among several possible explanations, interactions between neutralising antibodies against protein-linked N-glycans and RBC antigens have to be considered. [ … ]