Application of parietal cell autoantibody to histopathological studies

Parietal cell antibody (PCA) from the serum of a patient with type A gastritis was used for the immunohistochemical demonstration of human parietal cells not only in frozen sections but in paraffin-embedded biopsy specimens. The antigenicity was occasionally lost in paraffin sections of routine surgical materials. With the indirect immunoperoxidase technique, PCA clearly detected antigenic substances on the intracytoplasmic canalicular structures and focally on the apical plasma membranes. These intracellular localization patterns differed from those of intrinsic factor, which was present on fine vesicular structures along the intracytoplasmic canaliculi and apical plasma membranes. A few PCA-reactive cells were further demonstrated in normal pyloric glands, atrophic fundic glands with pseudopyloric gland metaplasia and cystic changes, a hamartomatous polyp in the fundic mucosa, and in heterotopic gastric mucosa in the duodenum. Developing parietal cells in the newborn stomach were also visualized by PCA. In one of 16 surgical specimens of gastric cancer, abortive gland lumens formed by the cancer cells were focally positive with PCA. Immunostaining with PCA was, therefore, a useful tool for the detection of pathological alterations of human parietal cells in routine histopathology specimens.