Detection of latent pernicious anaemia in iron-deficiency anaemia.

It has long been recognized that iron-deficiency anaemia and pernicious anaemia may occur in members of the same family (Faber and Gram, 1924 ; Maclachlan and Kline, 1926 ; Witts, 1930; Kaufmann and Thiessen, 1939). There are also numerous reports of pernicious anaemia developing in patients with a previous history of iron-deficiency anaemia (Callender and Denborough, 1957). More recently, in a review of 371 patients with iron-deficiency anaemia, Beveridge et al. (1965) found that 12 had overt or latent pernicious anaemia when first seen and that, on follow-up, three further patients developed latent pernicious anaemia and five more the overt disease. It is now established that a high proportion of patients suffering from Addisonian pernicious anaemia have in their serum an organ-specific antibody to gastric parietal mucosal cells. Using an immunofluorescent technique, Taylor et al. (1962) demonstrated the antibody in 85 % of 100 patients. With a similar technique Dagg et al. (1964) showed that the sera of 13 (20.8 %) of 64 patients with iron-deficiency anaemia contained the antibody, compared with only 4 (6.4%) in 64 matched control subjects ; this increased incidence in irondeficiency anaemia occurred only in those patients who also had a histamine-fast achlorhydria ; patients with free acid in the gastric juice had no higher incidence than the controls. In addition, Coghill et al. (1965) demonstrated that parietal-cell antibody was found almost exclusively in patients with hypochromic anaemia who also had biopsy evidence of atrophic gastritis. The auto-antibody to gastric mucosa in both pernicious anaemia and achlorhydric iron-deficiency anaemia appears to be identical. It would clearly be of practical value to be able to predict which patients with iron-deficiency anaemia might later develop pernicious anaemia. Since histamine-fast achlorhydria and antibody to gastric parietal cells occur in most cases of pernicious anaemia, it was thought likely that out of any large group of patients with iron-deficiency anaemia those who had both these tests positive would provide the main pool containing examples of latent pernicious anaemia. Out of a series of 114 patients presenting with iron-deficiency anaemia 22 were found who were both achlorhydric and had gastric-parietal-cell antibodies. In each of these patients investigations were carried out to detect the presence or absence of latent or overt pernicious anaemia.