A comparison of immunofluorescent assays to detect anti-granulocyte antibodies.
Three immunofluorescent assays were compared to detect anti-granulocyte antibodies (AGA) in patients with immune disorders: the granulocyte immunofluorescence test (GIFT), the avidin-biotin coupling test (ABCT), and the modified staphylococcal protein A test (MSPAT). The ABCT was more sensitive than both the GIFT and MSPAT for patient sera, but it also detected more positivity among random normal sera. Although less sensitive than the ABCT, the GIFT and MSPAT showed greater specificity and higher predictive values for positivity. When normal lymphocytes were run in parallel with normal granulocytes, 68% of positive AGA sera were nonreactive with lymphocytes, indicating the antibody specificity for granulocytes. Comparison of three direct and indirect immunofluorescent assays suggested a general co-existence of both cell-bound and circulating AGA. However, the direct test displayed minimal amounts of fluorescence for negative controls in contrast to the variable levels of fluorescence seen in normal sera for the indirect test.
D001323:Autoantibodies / Q000032:analysis*; D001360:Avidin; D001710:Biotin; D005455:Fluorescent Antibody Technique; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D007154:Immune System Diseases / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D013205:Staphylococcal Protein A
D001323:Autoantibodies; D013205:Staphylococcal Protein A; D001360:Avidin; D001710:Biotin