Helicobacter pylori infections in IgA deficiency: lack of role for the secretory immune system.

During the last years considerable attention has been focused on the possibility of the development of an oral vaccine against Helicobacter pylori. However, Helicobacter infection is known to be life-long, despite a vigorous immune response, and the hypothesis that an increased local production of secretory IgA in the gastric mucosa, due to vaccination, should protect against the colonization of the bacterium may therefore be questioned. In this study, when comparing the seropositivity and titre against H. pylori in IgA-deficient patients and age-related normal blood donors, it appears that lack of secretory IgA does not seem to have any major influence on the prevalence of the infection, nor is it reflected in titres of specific IgG antibodies. These results many argue against a pivotal role for IgA in the defence against Helicobacter, and raise questions about current strategies for the development of an oral vaccine against H. pylori and may point to a need for alternative therapeutic strategies.