Genetic Determinants and Clinico-Pathological Outcomes of Helicobacter Pylori Infection

Helicobacter pylori is a spiral Gram-negative bacterium with a relatively small genome and is known to be the most common human bacterial infection worldwide; infecting about half of the world's population. The bacterium represents one of the most successful human pathogens; inducing severe clinical symptoms only in a small subset of individuals; thus signifying a highly balanced degree of co-evolution of H. pylori and humans. The prevalence of Helicobacter pylori infection varies greatly among countries and among population groups within the same country; but is falling in most developed countries. The clinical course of H. pylori infection is highly variable and is influenced by both microbial and host factors including genetic susceptibility while the pattern and distribution of inflammation correlate strongly with the risk of clinical sequelae; namely duodenal or gastric ulcers; mucosal atrophy; gastric carcinoma; or gastric lymphoma. Cytokine gene polymorphisms directly influence inter-individual variation in the magnitude of cytokine response; and this clearly contributes to an individual's ultimate clinical outcome. Polymorphisms in genes coding for innate immune factors have also been incriminated in the pathogenesis of H. pylori related disease; while promoter hypermethylation of tumor suppressor genes is considered an important factor in carcinogenesis and known to be present in H. pylori associated gastric tumors. Functional genomics may fill many of the gaps in our understanding of the pathogenesis of H. pylori infection and accelerate the development of novel therapies; including H. pylori specific antimicrobial agents

Correlation of Serum Anti-Helicobacter pylori Immunoglobulin A (IGA) with Histological Parameters of Chronic Gastritis in Ibadan; Nigeria

Background: The seroprevalence of anti-H. pylori IgA antibodies has been reported to vary among populations and in relation to strains of Helicobacter pylori bacterium. However; there has been conflicting reports on the association between IgA serological status and the histological variables of chronic gastritis. This study was therefore conducted to clarify this relationship. Method : Using an ELISA based commercial kit; anti-H. pylori IgA antibody tests were performed on 65 dyspeptic patients and 65 age- and ex-matched controls. The gastric biopsies of these patients were also examined histologically for the degrees of inflammation; activity; intestinal metaplasia and atrophy. The CagA status of the patients had been determined previously. Results: There was an anti-H. pylori IgA antibody prevalence of 67.7in dyspeptics and 56.9in non-dyspeptic individuals. No correlations were observed between serum H. pylori IgA antibody and the graded parameters of chronic gastritis in dyspeptic patients; although twice more patients with mild gastric inflammation were found among IgA positive than among IgA negative patients. However; a statistically significant relationship was established between serum IgA positivity and the CagA status of the patients (p = 0.028). Conclusion: The seroprevalence of anti-H. pylori IgA antibody is high in our environment. Serum IgA status may be associated with milder degrees of gastritis in our patients but a larger cohort of patients is needed to confirm this. There seems to be a good agreement between serum IgA and CagA statuses among dyspeptic patients

Infectious Agents and Cancer

The epidemiology of several types of cancers indicate the involvement of several transmissible agents in their development; and in most cases; these seem to be viruses. The classic examplesare Burkitt's lymphoma; nasopharyngeal carcinoma (EBV); hepatocellular carcinoma (HBV); and cervical carcinoma (HPV). Most of these cancers show substantial variations in their incidencein different parts of the world and in particular countries; they present significant health problems. Worldwide; infections account for up to 20of all cancers. Also; there is now ample evidence implicating infection with the Helicobacter pylori in the occurrence of gastric carcinoma and gastric lymphoma; and infection with Schistosoma haematobium in the occurrence of the squamous cell carcinoma of the urinary bladder.The impact of these infections on the burden of cancer worldwide is becoming increasingly evident because they are largely responsible for the cascade of opportunistic malignancies associated with AIDS. The burden is heaviest among populations in developing countries; reflecting the impact of very early infection with these agents on subsequent risk of cancer. There are currently no vaccines available to prevent these chronic infections; other than for HBV. As a result; changes in behaviour hold the most promise for prevention