Anti-parietal cell antibody has been reported in nearly all patients with pernicious anaemia in past studies, in contrast with anti-intrinsic factor (IF) antibody which occurs in only 50-70% of such patients. However, observations in the more diverse patient population at our hospital suggest that these prevalences, originally described in predominantly elderly, white patients of European origin, no longer apply. Anti-IF antibody was found in 70% of the 324 patients, with blacks (84%) and Latin Americans (69%) having a significantly higher prevalence than whites (55%). In contrast, only 55% of the 266 patients tested had anti-parietal cell antibody. It was noteworthy that this low rate was similar in all racial groups. However, patients lacking anti-parietal cell antibody were significantly younger than those who had the antibody (54.8 +/- 17.8 vs 59.6 +/- 16.2 years, P = 0.022). Overall, a striking 30% of all patients had anti-IF antibody but not anti-parietal cell antibody, while only 13% had the latter antibody without having anti-IF antibody. This pattern was particularly striking among black patients. An interesting incidental observation was that gastrin levels were not associated with antibody status, but were significantly higher not only among women than among men but also among white and black patients than among Latin-American patients. The findings show that anti-parietal cell antibody is not found nearly as often in pernicious anaemia as has been reported in the past, and thus has no value as a diagnostic tool in pernicious anaemia. They also suggest clues to different expressions of pernicious anaemia or of its immunologic response, particularly among younger patients with the disease.