Abstract
Background: Cold agglutinin syndrome (CAS) is associated with various diseases. Several studies of CAS associated with coronavirus disease 2019 (COVID-19) reported hemolytic anemia and thrombosis; however, the clinical significance of cold agglutinins (CA) in patients with COVID-19 is unclear. Here, we present two cases of CA identified in the context of COVID-19 without hemolytic anemia and clotting.
Case report and discussion: Two patients with no known risk factors for CA were diagnosed with COVID-19; peripheral blood smears reveal red blood cells (RBCs) agglutination. These patients showed a high CA titer. We confirmed retrospectively that the CA was an anti-I antibody. The two COVID-19 cases with a high CA titer showed no hemolysis or thrombosis. Mycoplasma pneumoniae is known to cause CAS, but not all patients who have a high CA titer show hemolysis. Coagulation abnormalities are documented in severe COVID-19 cases. Although CA increases the risk of thrombosis in those with lymphoproliferative diseases, the role of anti-I antibodies in COVID-19 is unclear. The impact of CAS on clinical presentations in COVID-19 remains a matter of verification.
Conclusions: A high CA titer was identified in COVID-19 patients without hemolytic anemia and clotting. Anti-I antibodies were identified. Further studies are required to clarify the pathophysiology of CA in COVID-19.
Keywords: COVID-19; anti-I antibody; cold agglutinin; red blood cells.
【저자키워드】 COVID-19, red blood cells, Cold Agglutinin, anti-I antibody, 【초록키워드】 coronavirus disease, Diseases, thrombosis, severe COVID-19, antibody, risk, risk factor, Peripheral blood, Hemolysis, pathophysiology, Patient, red blood cells, red blood cell, Mycoplasma pneumoniae, clinical presentation, CAS, COVID-19 patient, hemolytic anemia, COVID-19 case, syndrome, lymphoproliferative diseases, abnormality, RBCs, reported, diagnosed, required, Two patient, increase, patients with COVID-19, 【제목키워드】 antibody, patients with COVID-19,