GPC antibodies are present in 95% of patients with pernicious anaemia (an endocrine autoimmune disorder) and up to 30% in iron deficient anaemia. GPC antibody is also found in association thyroid disease. In about 10-15% of older normal individuals its occurrence increases with ageing. It is recommended that patients harbouring GPC antibodies should be assessed for antibodies to intrinsic factor (70kDa glycoprotein), secreted by the parietal cells, that transports vitamin B12.

This antibody reacts with H⁺K⁺-ATPase in the parietal cells.

Image: Rodents stomach stained with IgG from patient. Note, cell cytoplasm of the gastric parietal cells in green while the nuclei are unstained black. Caution must be exercised as heterophile antibody can also give similar staining distribution.