寒冷凝集素高値を呈したEvans症候群の小児例

Abstract

Evans syndrome (ES) is a disorder in which autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP) occur simultaneously or serially. Most AIHA in ES is warm-AIHA in which anti-RBC IgG antibodies are the main body causing hemolysis. In this report, we describe a case of ES diagnosed as warm-AIHA but with a markedly high level of cold agglutinin (CA), where cold-AIHA was ruled out. A 9-year-old girl presented to the clinic with headache and was pale. There was no past history or family history of autoimmune disease. On admission, she was markedly anemic and thrombocytopenic with a positive direct Coombs test. A bone marrow examination revealed increased erythroid cells and megakaryocytes. The CA titer was very high of 2,048-fold, but cold-AIHA was considered negative because of the absence of IgM elevation, improvement of anemia with steroid therapy, and absence of symptoms due to cold exposure. She was diagnosed as ES with warm-AIHA and ITP. To our best knowledge, this is the first case of ES with high titers of CA. Long-term follow-up into adulthood is important in children with ES because of the high incidence of subsequent autoimmune disease after remission, while the association of CA was unknown.