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Cold agglutinin anti-I antibodies in two patients with COVID-19
Hiroharu Imoto1,2, Satoshi Yoshioka1, Daishi Nakagawa1
1Department of Hematology, Kobe City Medical Center General Hospital, Kobe, Japan.
Insights
High cold agglutinin (CA) titers were found in two patients with COVID-19, but without hemolytic anemia or clotting. This suggests a complex relationship between CA and COVID-19. Further research is needed.
Area of Science:
- Hematology
- Infectious Diseases
- Immunology
Background:
- Cold agglutinin syndrome (CAS) is linked to various conditions, with COVID-19 cases showing hemolytic anemia and thrombosis.
- The clinical relevance of cold agglutinins (CA) in COVID-19 patients remains uncertain.
- This study investigates CA in COVID-19 patients presenting without typical CAS complications.
Observation:
- Two patients diagnosed with COVID-19, without prior risk factors for CA, exhibited red blood cell (RBC) agglutination on peripheral blood smears.
- Both patients presented with high CA titers, identified as anti-I antibodies.
- Neither patient displayed signs of hemolysis or thrombosis despite the high CA titer.
Findings:
- A high titer of anti-I antibodies (CA) was detected in COVID-19 patients.
- The presence of high CA titers did not correlate with hemolytic anemia or thrombosis in these cases.
- This contrasts with known associations between CA and hemolysis, particularly with Mycoplasma pneumoniae infections.
Implications:
- The findings suggest that high CA titers in COVID-19 may not always lead to hemolysis or thrombosis.
- Further investigation is required to understand the specific pathophysiology of CA in the context of COVID-19.
- Clarifying the role of anti-I antibodies in COVID-19 is crucial for understanding disease mechanisms and potential complications.
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.
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