Abstract
Myelodysplastic syndrome (MDS) is a hematopoietic disorder characterized by both bone marrow failure and hematopoietic malignancies. It has been shown that autoimmune diseases accompany MDS in 10%-30% of patients. Autoimmune hemolytic anemia (AIHA) is caused by production of autoantibodies against mature erythrocytes, and is diagnosed using the direct Coombs test. Although rare, there are Coombs-negative AIHA patients. In these cases, determination of the level of erythrocyte-associated IgG is critical for diagnosis. Here, we present a case of Coombs-negative AIHA associated with MDS. We treated the patient with the DNA demethylating agent azacitidine for MDS, and consequently, pancytopenia was markedly improved. In addition, myeloblasts in peripheral blood disappeared and the level of Wilms tumor gene mRNA, a marker of MDS progression, became undetectable. Interestingly, during the courses of azacitidine treatment, hemolysis markedly improved, suggesting that azacitidine was also effective in treating AIHA. Coombs-negative AIHA is rare, but it is important to evaluate erythrocyte-associated IgG if the direct Coombs test is negative in patients with hemolytic anemia associated with MDS. Our findings in the present case also suggest the efficacy of azacitidine for AIHA, and thus it is of interest to clarify the mechanism underlying the effect of azacitidine.
