High‐Titer, High‐Thermal‐Amplitude Cold Autoagglutinin Not Associated with Hemolytic Anemia

Abstract

An example of an unusual cold autoagglutinin is reported. The antibody was monoclonal IgMKappa able to fix complement, and, in the presence of albumin, had both a high titer (greater than 4,096 at 4 degrees C) and a wide thermal range (4-37 degrees C). The patient was closely followed over a 3-year period with no evidence of hemolysis ever documented, despite a persistently positive direct antiglobulin test and the presence of the cold autoagglutinin. In contrast to previous reports regarding cold-agglutinin disease, this case demonstrates that in vivo hemolysis is not always associated with cold autoagglutinins that in vitro show a high thermal range in the presence of albumin.

Lethal autoimmune hemagglutination due to an immunoglobulin A autoagglutinin with Band 3 specificity

“…It is unclear why a powerful warm autoagglutinin did not cause obvious hemolytic anemia. Similar cases of cold agglutinins of high‐thermal range without hemolysis have been reported and remain unexplained . Autoantibodies of IgM class may cause in vivo RBC agglutination.…”

Acute hemolysis of transfused A2 red cells by an auto‐HI antibody

“…Thus, although his anti‐HI autoantibody agglutinated A1 RBCs at 30°C in the presence of albumin, it did not appear to cause clinically significant hemolysis of his endogenous A1 RBCs. Although in vitro thermal amplitude screening tests that use albumin enhancement are highly sensitive and specific for clinically significant cold agglutinins, 2 in vivo hemolysis may not always be observed 21 . Presumably, his RBCs were protected from hemolysis by the reduced level of H antigen that is expected on A1 RBCs.…”

A high‐titer, high‐thermal‐amplitude autoanti‐B associated with acrocyanosis but no obvious hemolytic anemia

“…Four patients were described who had high‐titer (>1000) cold agglutinins that were not reactive at 30°C and who had no hemolytic anemia. Sniecinski and coworkers 26 described a case that showed that this correlation was not always true. Their patient, who had a high‐titer, high‐thermal‐amplitude cold autoantibody, was followed for 3 years and showed no signs of hemolytic anemia.…”