Autoimmune hemolytic anemia in COVID-19 patients, the « transmissible » direct Coombs test

Abstract

Background: Like other viruses, the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) appears to be responsible for several autoimmune complications. The occurrence of autoimmune hemolytic anemia has been described in several case reports. This AIHA was also noticeable by the important number of blood transfusions required for COVID-19 (coronavirus disease 2019) patients. By investigating RBC coating autoantibodies, this article attempts to clarify the autoimmune aspect of the anemia in the context of SARS-CoV-2 infection. Results: A large population of COVID-19 patients selected at Saint-Luc University Hospital showed an average of 44% DAT positivity. In this population, the intensive care patients were more prone to DAT positivity than the general ward patients (statistically significant result). The positive DAT appeared « transmissible » to other RBCs via COVID-19 DAT-positive patient’s plasma. Conclusion: The strongest hypothesis explaining this observation is the targeting of cryptic antigens by autoantibodies in COVID-19 patients.