Helicobacter pylori: bacterial factors and the role of cytokines in the immune response.

Helicobacter pylori is a gram-negative micro-aerophilic bacterium that is widely distributed geographically and causes chronic gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. Bacterial virulence factors play an important role, since the virulent strains are more aggressive and increase the risk of developing severe clinical manifestations; in addition, other determinant factors are the nutritional state and the immune response of the host. Studies on humans, non-human primates, and rodents have reported that regulating proteins of the Th1 phenotype predominate in the immune response to the bacterial infection. The cytokines produced by this phenotype, are not very effective in eradicating the microorganism and furthermore, contribute to gastro-duodenal pathogenesis. Gastric inflammation in patients infected with H. pylori has been characterized by increased production of IL-1, IL-6, IL-12, IL-18, TNF-alpha, and IFN-gamma. Many prophylactic and therapeutic strategies have been researched using experimental animals. The utilization and effectiveness of vaccination on humans requires more study.

A possible defective estimation of antineutrophil cytoplasmic antibodies in systemic lupus erythematosus due ot the coexistence of periodontitis: preliminary observations

The objectives of this study is to determine if periodontitis-related ANCA hinder the accurate estimation of this kind of autoantibodies in systemic lupus erythematosus (SLE), due to the frequent coexistence of SLE and periodontitis, and the high incidence of antineutrophil cytoplasmic antibodies (ANCA) in this periodontal condition. Thirty SLE, thirty periodontitis lacking systemic involvement patients, and twenty healthy controls were utilized in this study. The periodontal condition and the presence of ANCA in sera of all individuals was carefully evaluated. For ANCA determination an EIA essay was utilized, directed to a neutrophil granular extract and six neutrophil granule proteins. Sixty percent of SLE patients had periodontitis, and sixty-five percent were ANCA positive. Eighty three percent of all ANCA cases were coexisting with periodontitis. A significant association (p > 0.005) between periodontitis and ANCA was found (Chi Square Test). Fifty percent of the patients with periodontitis lacking systemic involvement were ANCA positive. The results obtained in this study suggest that the figures of ANCA previously reported for SLE, might be overestimated due to the inadvertent presence of periodontitis