[Flow cytometric studies of anti-granulocyte antibodies]

An indirect immunofluorescence test using anti-granulocyte antibodies was developed to examine many sera samples in a one-step procedure by flow cytometry. Granulocytes obtained from several random donors were fixed with 0.5% paraformaldehyde solution on the first day, and the fluorescence intensity of granulocytes that had reacted with sera was measured on the following day. Non-specific reactions with isoantibodies, i.e., anti-A, anti-B, or serum IgG had no influence on the fluorescence intensity. Therefore, anti-granulocyte antibodies from a patient with immune neutropenia and patients with febrile transfusion reactions can be studied using this method. The results suggest that the IgG-antibody from a patient with immune neutropenia is granulocyte-specific and its subclass is IgG2.