Hemoglobin H Disease Complicated by Autoimmune Hemolytic Anemia: A Case Report

Abstract

Hemoglobin H disease is a genetically transmitted disease and its main clinical manifestation is congenital microcytic hemolytic anemia. It has been rarelycomplicated by autoimmune hemolytic anemia (AIHA). Herein we report a case of 20-year old woman who firstly presents with severe hemolytic anemia without hepatosplenomegaly, Hb 3.3 g%, Hct 11.6 %, MCV 98.6 fL, MCH 27.8 pg, NRBC 32/100 WBC, reticulocyte 19.4%, direct and indirect Coombs’ tests +2. She is diagnosed as severe hemolytic crisis due to AIHA and treated with corticosteroid and later danazol, cyclophosphamide and azathioprine, sequentially. She does not completely respond to therapy, her Hb levels fluctuate between 6.0 to 9.2 g%, mean 7.6+1.6 g%, MCV 77.8+3.0 fL, MCH 22.0+1.3 pg. Hbelectrophoresis showsHb A2AHBart and genotype study confirms the diagnosis of Hb H disease. At first, thalassemia is overlooked because the MCV and MCH levels appear normal until the hemoglobin concentration is partially raised following the treatment of AIHA and the MCV and MCH become obviously low. AIHA may be associated with thalassemia because the red blood cells in thalassemia always have bizarre shape, fragmentation, membrane deformation or alloantibody binding, leading to expose new antigens and promote an immune reaction, resulting in AIHA. In conclusion, if the patients with AIHA do not respond well to steroid or other immunosuppressants, thalassemia such as Hb H disease should be excluded particularly in case of new onset of the low MCV.