IMMUNE RESPONSE

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This is a stained section of inflamed gastric tissue. Most cells in this picture are lymphocytes or plasma cells. Neutrophils can be seen invading glands.

Researchers are still in the process of understanding how H. pylori is able to survive in the wake of an intense immune response. This response is characterized by and increase in IgG antibodies in the blood plasma which will remain present for months following infection. Proucion of IgA antibodies also increase upon infection by H. pylori. These cells have been shown to coat bacterial cells in vivo. An intense inflammatory response also follows infection by H. pylori. This inflammation leads to infiltration of numerous B and T cells into the gastric mucosa. This is the point in the response where researchers have postualted exists the mechanism by which H. pylori wards off the immune response. Studies have shown that H. pylori is able to increase the number of T cells infiltrating the mucosa. It is thought that this ability to influence T cell activity may be the key to H. pylori's evasion of the immune response. Others have postulated that the immune response may in fact promote infection. Such theories are based upon studies with AIDS patients who seem to show lower rates of infection that age-matched subjects without AIDS. The decreased intensity of the immune response may in fact be holding off infection by H. pylori.