Assay of the Autohumoral Antibody that Neutralizes the Vitamin B12Combining Site of Intrinsic Factor in Serum from Patients with Pernicious Anemia

Abstract

A simple rapid method is described to assay the antibody (combining site antibody—CSAB) in serum from patients with pernicious anemia which neutralizes the vitamin B₁₂ combining site of human intrinsic factor. Of the serums obtained from patients in whom pernicious anemia was diagnosed previously, 50 per cent were found to contain the antibody. Thirteen of fourteen patients in whom pernicious anemia was not diagnosed previously were found to have the antibody in their serums, whereas patients with macrocytic anemia due to dietary folic acid deficiency, gastrectomy, malabsorption and Dilantin toxicity did not have the antibody.