Serum antibodies to selected Helicobacter pylori antigens are associated with active gastritis in patients seen at the University Teaching Hospital in Lusaka, Zambia.

Abstract

Little is known about specific bacterial characteristics of Helicobacter pylori (H. pylori) infection influencing gastric carcinogenesis in Zambia. The aim of this study was to evaluate the associations between pre-selected H. pylori antibodies with gastric cancer, premalignant lesions and active gastritis. This was cross-sectional study with multiple comparisons of patients with gastric cancer (GC), gastric premalignant (GP) lesions and active or chronic gastritis. A fluorescent bead-based antibody multiplex serology assay was used to quantify antibodies to thirteen immunogenic H. pylori antigens. Logistic regression models were used to examine the associations. Included were 295 patients with: 59 GC, 27 GP lesions, 48 active and 161 chronic gastritis. Overall, 257/295 (87%) were H. pylori positive. H. pylori seropositivity was not associated with sex, age, body mass index, socio-economic status, HIV infection, alcohol consumption or cigarette smoking (p-values all above 0.05). When compared to the patients with chronic gastritis, the presence of catalase and cinnamyl alcohol dehydrogenase (Cad) antibodies was positively associated with GP lesions (OR 3.53; 95% CI 1.52-8.17 and OR 2.47; 95% CI 1.08-5.67 respectively). However, seropositivity to Cad antibodies was significantly lower in GC patients (OR 0.28; 95% CI 0.09-0.83). Compared to chronic, active gastritis was significantly associated with (p<0.05) H. pylori sero-positivity (OR 9.46; 95% CI 1.25-71.52) and specific antibodies including cytotoxin-associated gene A, vacuolating cytotoxin A, Helicobacter cysteine-rich protein C, hypothetical protein HP0305 and outer membrane protein HP1564. Among Zambian patients seen at a single center, antibodies to H. pylori (CagA, VacA, Omp, HcpC, HP0305 and HpaA) were associated with active gastritis.