Antibody Activity against Hog Intrinsic Factor in Pernicious Anaemia

S ummary . The sera of 100 adult patients with Addisonian pernicious anaemia not previously exposed to hog intrinsic factor were tested for antibody activity against hog intrinsic factor by the charcoal method: 55 sera containing antibody to human intrinsic factor showed antibody activity against hog intrinsic factor; 45 sera had no demonstrable antibody activity against human or hog intrinsic factor. A high degree of cross reactivity between antibody to human intrinsic factor and hog intrinsic factor was thus demonstrated in vitro .
Hog intrinsic factor was equally effective in potentiating vitamin B₁₂ absorption to normal levels in pernicious anaemia patients with and without circulating antibody active against hog intrinsic factor. Antibody to intrinsic factor circulating in the blood was therefore considered to have no effect on hog intrinsic factor in the human gastrointestinal tract. The possibility of a direct effect of circulating antibodies on the production and/or release of endogenous intrinsic factor by the gastric mucosa could not be excluded.