Researchers reported the first case of cold agglutinin syndrome (CAS)/cold agglutinin disease (CAD) secondary to COVID-19 in a patient and published their results in Internal Medicine. The patient was successfully treated with corticosteroids.

“Although corticosteroids are not a standard therapy for CAS, they might be effective for CAS secondary to COVID-19,” the researchers wrote. CAD can sometimes develop secondary to viral and bacterial infections and autoimmune and lymphoid disorders.

A number of studies have also been published that report cases of CAD secondary to SARS-CoV-2 infections. However, the optimal treatment course in such cases has not been determined to date.

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In the present study, a team of researchers led by Koya Ariyoshi, MD, from the Department of Clinical Medicine at Nagasaki University in Japan reports the case of a 72-year-old Japanese woman with a history of hypertension. The patient had been experiencing dyspnea and cough for 2 weeks before presentation.

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She had severe hemolytic anemia with a hemoglobin level of 4.7 g/dL and was diagnosed with COVID-19 as well as monoclonal gammopathy of undetermined significance (MGUS), a disease characterized by the presence of monoclonal or M protein in the blood. 

The patient was treated with corticosteroids against COVID-19 and the anemia also responded to the treatment. However, it was not solved even after recovery from COVID-19 and blood transfusion and the patient required maintenance therapy with corticosteroids.

Based on the case of this patient, the researchers concluded that corticosteroids could be a potential treatment option for patients with COVID-19 related secondary CAD that persists and that is complicated with MGUS.

More research is necessary to assess the potential benefits of corticosteroids in CAD secondary to COVID-19 and the possible relationship between COVID-19 and MGUS.


Tsukamoto Y, Umeda M, Muto Y, et al. Severe anemia due to cold agglutinin syndrome in a COVID-19 patient with IgM monoclonal gammopathy of undetermined significance successfully treated with corticosteroids. Intern Med. Published online March 26, 2022. doi:10.2169/internalmedicine.8647-21