Anti-granulocyte antibody screening with extracted granulocyte antigens by a micro-mixed passive hemagglutination method.

BACKGROUND AND OBJECTIVES Serologic tests for granulocyte antibodies, i.e., the granulocyte agglutination test and the granulocyte immunofluorescence test, require panels of typed granulocytes that cannot be preserved for more than a few hours. We have developed a new method in which granulocyte antigens, extracted into saline containing 3% sucrose, are coated onto U-type Terasaki plates. With this new method, we evaluated the micro-mixed passive hemagglutination test (EG-MPHA) for screening for granulocyte antibodies. MATERIALS AND METHODS We tested the ability of the EG-MPHA to detect granulocyte antigens using 5 human antibodies specific for NA1, NA2, NB1, 5b, and Sar(a), and 8 different monoclonal antibodies for NA1, CD11a, CD11b, CD13, CD16, CD18 and HLA class I. Sera from 94 alloimmunized patients were screened by the chloroquine-treated EG-MPHA method. RESULTS NA1, NA2, NB1, 5b, Sar(a), CD11a, CD11b, CD13, CD16, CD18 and HLA class I antigens were present in the extracted granulocyte antigen preparation. CD11b and HLA class I antigens were removed when the extracted granulocyte antigens were treated with chloroquine. Granulocyte antibody screening of sera from alloimmunized patients showed that approximately 30% of the anti-HLA-positive and 10% of the anti-HLA-negative sera were positive for granulocyte antibody by the chloroquine-treated EG-MPHA. The extracted granulocyte antigen panels could be stored frozen for at least 1 year at -80 degrees C. CONCLUSION This new method is preferable for screening for granulocyte antibodies. In addition, it has the advantage of requiring only 5 microl of serum for each test.