The detection of granulocyte alloantibodies with an indirect immunofluorescence test

An indirect immunofluorescence technique for the detection of alloantibodies against granulocytes was developed. A major problem was the unspecific fluorescence of granulocytes, due to unspecific adherence of immunoglobulins to the cell membrane. This could be suppressed by the prefixation of the granulocytes with paraformaldehyde. The developed test proved to be specific and sensitive and to have a high reproducibility. Strongly positive reactions were obtained with antisera containing granulocyte-specific agglutinins or granulocyte-cytotoxins, but also with some sera that did not react in either the agglutination or the cytotoxicity test. HLA antisera also gave positive reactions, but strong anti-A, anti-B or anti-D sera did not react. With this technique leucocyte antibodies can be detected in a higher percentage of patients with febrile transfusion reactions.