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A dual antiglobulin test for the detection of weak or nonagglutinating immunoglobulin M warm autoantibodies
Author(s) -
Bartolmäs Thilo,
Salama Abdulgabar
Publication year - 2010
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2009.02533.x
Subject(s) - cold agglutinin , autoantibody , autoimmune hemolytic anemia , prednisolone , hemolysis , medicine , antibody , azathioprine , coombs test , immunology , cyclophosphamide , hemolytic anemia , immunoglobulin m , subclass , immunoglobulin g , gastroenterology , chemotherapy , disease
BACKGROUND: Immunoglobulin (Ig)M warm autoantibodies (AABs) usually cause severe autoimmune hemolytic anemia (AIHA) and, in some cases, red blood cell (RBC)‐bound IgM cannot be detected. We describe a simple dual antiglobulin test (DDAT) for diagnosing such cases. STUDY DESIGN AND METHODS: A patient with erroneously suspected cold agglutinin syndrome was investigated. The direct antiglobulin test (DAT) was performed using standard techniques and dual (two stages) antiglobulin reagents (IgG rabbit anti‐human IgM, IgG goat anti‐rabbit IgG). RESULTS: A cold agglutinin syndrome was diagnosed initially, as the patient's serum was reactive with RBCs at a temperature of 28°C or less, and the DAT was strongly positive with anti‐C 3 d. Six months later, the patient was reexamined at this hospital due to progressive hemolysis. His RBCs were found to be coated with IgM warm AABs that only became detectable using a DDAT, and his serum contained only a weak cold agglutinin. The hemolysis remained refractory to treatment with prednisolone and also prednisolone plus azathioprine, but gradually improved after treatment with prednisolone plus cyclophosphamide. CONCLUSION: Weak or nonagglutinating RBC‐bound IgM warm antibodies can be identified by the presented DDAT.