Antibody to Intrinsic‐Factor‐Vitamin‐B₁₂ Complex in Pernicious Anaemia

Abstract

SUMMARY Serum from some patients with pernicious anaemia contains antibody activity to human intrinsic factor‐57CoB12 complex (IF‐57CoB12) which can be detected by co‐precipitation of IF‐57CoB12) with the globulin fraction precipitated with 45 per cent ethanol. The characteristics of this antigen‐antibody reaction include some dissociation of antigen from antibody during precipitation, and ready cross‐reaction of antibody with IF to which vitamin B12 is not bound. The IF‐B12 antigen also cross‐reacts with anti‐intrinsic‐factor antibody, as measured by the charcoal adsorption technique. This co‐precipitation technique may be to determine whether small quantities of B12‐binding material have the immunological characteristics of intrinsic factor. Although the anti‐IF antibody present in the blood of many patients with pernicious anaemia may be responsible for this anti‐IF‐B12 antibody activity, it is possible that a separate antibody system exists which is directed against IF‐B12.

Possible Association of Paget’s Disease of Bone and Pernicious Anaemia

“…I sraels [1963], in discussing Pernicious Anaemia, recognises a group of patients with this pattern of B12 excretion and comments that this abnormality cannot be attributed to malabsorption in all of them. The failure of oral intrinsic factor to augment the excre tion of radioactive B12 may be due to the presence in the intestines of antibody to the B12 -intrinsic factor complex [Cooper and Yates, 1967]. In Cases 4 and 5 there is inadequate evidence for the diagnosis of Pernicious Anaemia.…”

Absence of Intrinsic Factor from Human Portal Plasma during 57CoB12 Absorption in Man

“…Antibody activity to IF-B1, complex was assayed by a co-precipitation technique (Cooper and Yates, 1967). The solution to be tested was incubated with serum containing antibody to IF-BIZ, and then a globulin fraction was precipitated with 45 per cent ethanol.…”