A potential double role of anti-Lewis X antibodies in Helicobacter pylori-associated gastroduodenal diseases

In this study, we found Lewis X (Le(X)) determinants on 68% of Helicobacter pylori isolates from patients with chronic gastroduodenal diseases. Anti-L e(X) IgG were detected more frequently in the sera from dyspeptic children and adults (45 and 46%), with or without proved (culture) H. pylori infecti on, than in the sera from healthy individuals (14%, and 25%). In contrast, the prevalence of anti-Le(X) IgM was higher in the groups of healthy indivi duals than in the groups of dyspeptic patients. Moreover. anti-Le(X) monocl onal antibody of IgM class enhanced the uptake of Le(X)(+) but not Le(X)(-) H. pylori isolates by phagocytes. In the sera from some dyspeptic patients , we detected Le(X)-anti-Le(X) IgG immune complexes (Le(X) ICs). There was a great difference between children and adults as regards the presence of L e(X) ICs. The immune complexes were found in the sera from nine out of 29 ( 27%) H. pylori-infected and three out of eight (37%) uninfected adult dyspe ptic patients. In comparison, Le(X)-anti-Le(X) IgG ICs were detected only f or two out of 18 (11%) H. pylori-infected children. Le(X) ICs were not foun d in the sera from healthy individuals. Our results suggest that anti-Le(X) IgM may play a protective role in H. pylori infections. In contrast, anti- Le(X) IgG and particularly Le(X)-anti-Le(X) IgG ICs might contribute to the pathogenesis of chronic H. pylori infections. (C) 2001 Federation of Europ ean Microbiological Societies. Published by Elsevier Science B.V. All right s reserved.