A Comprehensive Diagnostic Algorithm for Direct Antiglobulin Test-Negative Autoimmune Hemolytic Anemia

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K08651
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Laboratory medicine
• Research Institution: Jichi Medical University
• Principal Investigator: Kamesaki Toyomi 自治医科大学, 医学部, 教授 (90316513)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 溶血性貧血 / 自己免疫 / 血清学

Outline of Final Research Achievements

Direct antiglobulin test (DAT)-negative warm autoimmune hemolytic anemia (AIHA) is mainly caused by three mechanisms: red blood cell (RBC)-bound immunoglobulin (Ig)G below the detection limit of routine DAT; RBC bound IgA or IgM; or low-affinity autoantibodies. Although most cases of DAT-negative AIHA are thought to be caused by RBC-bound IgG, and combinatory serological analyses are recommended, the relative ratios of each mechanism have not been clarified. The patients with undiagnosed hemolytic anemia and negative conventional tube method-DAT (TM-DAT) were investigated using anti-IgA and anti-IgM sera, and column agglutination method-DAT (CM-DAT), in addition to radioimmunological quantitation of RBC-bound IgG. Relative ratios of patients with DAT-negative AIHA resulting from RBC-bound IgG, RBC-bound IgA, RBC-bound IgM, and low-affinity IgG were estimated as 80, 4, 1 and 15%, respectively. A new classification and diagnostic algorithm for DAT-negative AIHA were proposed.

Free Research Field

免疫血液学

Academic Significance and Societal Importance of the Research Achievements

全国で数百例程度の希少疾患であるクームス陰性AIHAの3つの発症機序について、1つの研究室に症例検体を集約して解析することにより、3つの機序を考慮した包括的な診断方法を確立し、それぞれの頻度を明らかにした。また、従来の検査法を組み合わせることにより、新たな分類を見出し、診断分類として提唱した。今後それぞれの診断分類における臨床的な特徴や予後などの解析を行う上で、基礎的なデータが得られたと考える。