Epidemiology of Helicobacter pylori infection and public health implications

Helicobacter pylori infection and primary open-angle glaucoma: is there a connection?

Glaucoma, the most common form of which is primary open-angle glaucoma (POAG), is a neurodegenerative disease which is the second most common cause of blindness worldwide. Among the factors that have been implicated in the pathophysiology of this disease is infection with Helicobacter pylori. This alleged association has caused a great deal of scientific discussion during the past decade, as the establishment of such a correlation might lead to therapeutic applications for all glaucoma patients. In this review, we assess all relevant major studies and trials in an effort to elucidate the issue.

Serological prevalence of Helicobacter pylori infection in Saxony-Anhalt, Germany, in 2010

Epidemiological studies from different countries have shown a steady decline of the prevalence of Helicobacter pylori infection. In order to investigate the current seroprevalence of H. pylori infection in the area of Magdeburg, a city of the former East Germany, H. pylori antibodies of patients presenting in our emergency wards were analyzed. In total, 2,318 patients (1,181 males and 1,137 females) enrolled between September 2009 and August 2010 were tested for immunoglobulin G (IgG) against H. pylori and anti-CagA antibodies by specific enzyme immunoassay (EIA). Patients with either anti-H. pylori IgG or anti-CagA antibodies were classified as H. pylori positive, whereas the lack of both antibodies led to the assignment of an H. pylori-negative status. The overall seroprevalence of H. pylori infection was 44.4% (n = 1,029 out of 2,318) and did not differ in relation to sex. The proportion of CagA-positive samples was 43.3% of all H. pylori-positive individuals (446 out of 1,029). The seroprevalence showed a birth cohort effect (0 to 20 years of age, 14.6%; 21 to 30 years, 22.4%; 31 to 40 years, 40.6%; 41 to 50 years, 45.5%; 51 to 60 years, 50.8%) up to the age of 60, while it remained between 40.7% and 50.5% for the following decades. Patients younger than 30 years were significantly less H. pylori positive (21.1%) than those older than 30 years of age (47.7%; P < 0.01), whereas CagA status was similar (44.3 versus 43.3%). Notably, young women (<30 years old) had significantly higher CagA positivity (59.3%) than corresponding men (32.5%; P = 0.016). Taken together, seroprevalence of H. pylori infection shows a significant drop in subjects born after 1980 in Saxony-Anhalt but still remains in the range of 40 to 50% in subjects born earlier.

IFN-γ plays an essential role in the pathogenesis of gastric lymphoid follicles formation caused by Helicobacter suis infection

In this study, we aimed to assess the role of helper T cells in the development of gastric lymphoid follicles induced by Helicobacter suis infection. C57BL/6J mice were orally inoculated with H. suis. Six weeks after infection, gastric lymphoid follicles were observed in the gastric mucosa by hematoxylin and eosin staining, and the number of follicles was increased throughout the infection period. An immunohistological examination showed that the lymphoid follicles were composed of B cells, CD4-positive helper T cells, and dendritic cells (DC). It was also revealed that the mRNA expression level of interferon-γ (IFN-γ) in the gastric mucosa was significantly increased at 12 weeks after infection. No gastric lymphoid follicles were detected in IFN-γ-deficient mice that had been infected with H. suis at 12 weeks after infection, although the development of lymphoid follicles in IL-4-deficient mice infected with H. suis was similar to that seen in the wild-type mice. In conclusion, IFN-γ, a Th1 cytokine, is deeply involved in the pathogenesis of gastric lymphoid follicles induced by H. suis infection, and it is suggested that CD4-positive T cells and DC aid in the expansion of gastric lymphoid follicles.