Helicobacter pylori infection in an urban African population

We have studied 221 adults drawn from an impoverished urban population with high human immunodeficiency virus (HIV) seroprevalence (35%) to determine the prevalence of gastroduodenal pathology and its relationship to serologi cal markers of Helicobacter pylori virulence proteins and other potential e nvironmental and immunological determinants of disease including HIV infect ion. Eighty-one percent were H. pylori seropositive, and 35% were HIV serop ositive. Urban upbringing and low CD4 count were associated with a reduced likelihood of H pylori seropositivity, as was current Ascaris infection, in keeping with recent evidence from an animal model, One hundred ninety-one adults underwent gastroduodenoscopy, and 14 had gastroduodenal pathology, M ucosal lesions were a major cause of abdominal pain in this population. Whi le the majority of patients with gastroduodenal pathology (12 of 14) were s eropositive for H. pylori, none were seropositive for HIV. Smoking was asso ciated with increased risk of macroscopic pathology, and a history of Mycob acterium bovis BCG immunization was associated with reduced risk. Antibodie s to H. pylori lipopolysaccharide were associated with pathology. HIV infec tion was associated with protection against mucosal lesions, suggesting tha t fully Functional CD4 lymphocytes may be required for the genesis of gastr oduodenal pathology.