Low Titer Cold Agglutinin Disease with Severe Hemolytic Attack

Abstract

We encountered a child case of low titer cold agglutinin disease (CAD) causing a severe hemolytic attack, though the cold agglutinin titer was extremely low. A 3-year-old boy was admitted to our hospital because of jaundice and drowsiness following fever and diarrhea. Laboratory examinations revealed normocytic normochromic anemia (hemoglobin; 5.7 g/dl), elevated levels of direct bilirubin and LDH, and low haptoglobin concentration, which suggested an acute attack of hemolytic anemia. Direct Coombs tests were strongly positive for C3bC3d, C3d and weakly positive for IgM, but negative for IgG. Although hemagglutination tests using the patient's serum were positive only in low temperature, the serum level of cold agglutinin was very low (1 : 32). After other forms of hemolytic anemia were ruled out, he was diagnosed with low titer CAD. He was kept in a warm room (30 degrees C), and treated with predonisolone and transfusion of warmed red blood cells because hemoglobin concentration was lowered to 3.9 g/dl the next day. He achieved remission, and had no recurrence of the disease for one and a half years.