An autoimmune disease in which sensitised LYMPHOCYTES destroy the PARIETAL cells of the STOMACH. These cells normally produce intrinsic factor, which is the carrier protein for vitamin B12 that permits its absorption in the terminal ileum. Without intrinsic factor, vitamin B12 cannot be absorbed and this gives rise to a macrocytic ANAEMIA. The skin and MUCOUS MEMBRANES become pale and the tongue smooth and atrophic. PERIPHERAL NEUROPATHY is often present, causing paraesthesiae (see under TOUCH), numbness and even ATAXIA. The more severe neurological complication of sub-acute combined degeneration of the cord is fortunately rarer. Treatment is with a monthly injection of vitamin B12.