Flow microfluorimetric analysis of autoantibody reactions with parietal cell surface membranes in pernicious anaemia

Using flow microfluorimetry (FMF), 60 sera from patients with pernicious anaemia (PA) were examined for immunoreactivity with the surface membranes of viable canine parietal cells. FMF analyses showed that the percentage of parietal cells giving a surface staining reaction with a fluorescence intensity greater than 50 arbitrary units was 44.5 +/- 17.5% for sera from 60 patients with PA compared to 13.7 +/- 2.7% for sera from 14 patients with chronic active hepatitis, 10.7 +/- 6.7% for sera from 10 patients with systemic lupus erythematosus and 16.5 +/- 4.4% for sera from 50 healthy persons. Surface staining detected by FMF was restricted to parietal cells and abolished by absorption with parietal cell enriched preparations but not by absorption with dog or rat hepatocytes, dog or rat kidney cells, human fibroblasts, human AB red blood cells or dog gastric microsomes. The intensity of the parietal cell surface staining reactions correlated with the presence of antibody reactions with parietal cell surfaces previously demonstrated by immunofluorescence microscopy but did not correlate with the presence of microsomal or intrinsic factor autoantibodies. The results provide further support for the presence of a parietal cell surface reactive autoantibody distinct from the conventional parietal cell microsomal autoantibody.