Respiratory diseases and Helicobacter pylori infection: is there a link?

Recent studies suggest an epidemiological association between Helicobacter pylori infection and several extra-gastroduodenal pathologies, including cardiovascular, rheumatic, skin and liver diseases. The observed associations might be explained by a role of H. pylori infection in the pathogenesis of certain extra-digestive disorders, as a variety of inflammatory mediators are activated by H. pylori infection. The present review summarizes the current literature, including our own studies, concerning the association between respiratory diseases and H. pylori infection. A small number of epidemiological and serologic case-control studies suggest that patients with chronic obstructive pulmonary disease have an increased seroprevalence of H. pylori. A frequent coexistence of bronchiectasis and H. pylori infection has also been found. Moreover, recent studies have shown an increased prevalence of H. pylori infection in patients with pulmonary tuberculosis and in those with lung cancer. On the other hand, bronchial asthma does not seem to be related to H. pylori infection. At present, there is no definite proof of a causal relationship between H. pylori and respiratory diseases. The primary evidence rests on case-control studies, concerning relatively small numbers of patients. Future studies should be large enough for moderate-sized effects to be assessed or registered reliably. The activation of inflammatory mediators by H. pylori infection might be the pathogenetic mechanism underlying the observed associations. Therefore, the role of genetic predisposition of the infected host, the presence of strain-specific virulence factors and the serum concentration of proinflammatory markers in H. pylori-infected patients with respiratory diseases need further evaluation.

Helicobacter pylori seroprevalence in patients with chronic obstructive pulmonary disease.

An increased seroprevalence of Helicobacter pylori (H. pylori) and especially of the high virulent cytotoxin-associated gene-A (CagA) positive strains has been found in several extragastroduodenal pathologies, characterized by activation of inflammatory mediators. Moreover, it has been reported that the risk of chronic bronchitis may be increased in H. pylori infected patients. The aim of the present study was to assess the seroprevalence of H. pylori and in particular of CagA-positive virulent strains in patients with chronic obstructive pulmonary disease (COPD). We evaluated 126 COPD patients (88 males and 38 females, aged 61.3+/-8.1 years) and 126, age and sex-matched, control subjects. All subjects enrolled underwent an enzyme-linked immunosorbent assay (ELISA) IgG serologic test for H. pylori and CagA protein. The prevalence of H. pylori infection in patients and controls was 77.8% and 54.7%, respectively (P<0.001) and that of CagA-positive H. pylori infection was 53.9% and 29.3%, respectively (P<0.001). Moreover, COPD patients had a significantly increased mean serum concentration of both anti-H. pylori IgG (118.3+/-24.4 vs. 61.9+/-12.9U/ml, P<0.001) and anti-CagA IgG antibodies (33.8+/-3.4 vs. 19.0+/-1.5U/ml, P<0.001). Finally, no statistically significant difference, as regards the spirometric values, was detected between H. pylori infected COPD patients and uninfected ones. In conclusion, H. pylori infection may be associated with COPD. Further studies should be undertaken to clarify the potential underlying pathogenetic mechanisms.

Helicobacter pylori infection and respiratory diseases: a review.

In the past few years, a variety of extradigestive disorders, including cardiovascular, skin, rheumatic and liver diseases, have been associated with Helicobacter pylori (H. pylori) infection. The activation of inflammatory mediators by H. pylori seems to be the pathogenetic mechanism underlying the observed associations. The present review summarizes the current literature, including our own studies, concerning the association between H. pylori infection and respiratory diseases. A small number of epidemiological and serologic, case-control studies suggest that H. pylori infection may be associated with the development of chronic bronchitis. A frequent coexistence of pulmonary tuberculosis and H. pylori infection has also been found. Moreover, recent studies have shown an increased H. pylori seroprevalence in patients with bronchiectasis and in those with lung cancer. On the other hand, bronchial asthma seems not to be related with H. pylori infection. All associations between H. pylori infection and respiratory diseases are primarily based on case-control studies, concerning relatively small numbers of patients. Moreover, there is a lack of studies focused on the pathogenetic link between respiratory diseases and H. pylori infection. Therefore, we believe that larger studies should be undertaken to confirm the observed results and to clarify the underlying pathogenetic mechanisms.

Helicobacter pylori seroprevalence in patients with chronic bronchitis.

BACKGROUND: A high Helicobacter pylori seroprevalence has been found in many extragastrointestinal disorders. Moreover, it has been reported that the risk of chronic bronchitis may be increased in H. pylori-infected patients. The aim of this study was to assess the H. pylori seroprevalence in patients with chronic bronchitis. METHODS: We evaluated 144 patients with chronic bronchitis (81 men and 63 women, aged 53.2+/-12.7 years) and 120 age and sex-matched control subjects. All enrolled subjects (bronchitic patients and controls) underwent an enzyme-linked immunosorbent assay (ELISA) IgG serologic test for H. pylori diagnosis. RESULTS: A correlation between age and H. pylori IgG level was detected for both bronchitic patients (r = 0.42; P = 0.004) and controls (r = 0.44; P = 0.004). H. pylori seropositivity in the chronic bronchitis group was significantly higher than that in controls (83.3% vs 60%; P = 0.007). The mean serum concentration of IgG antibodies against H. pylori was also significantly higher in patients with chronic bronchitis than in the control subjects (38.7+/-24.1 U/ml vs 25.9+/-19.3 U/ml; P = 0.02). CONCLUSIONS: Helicobacter pylori infection may be associated with chronic bronchitis. Further studies should be undertaken to confirm our results and to clarify the potential underlying pathogenetic mechanisms.