CROSS-REACTIVE ANTIGENS SHARED BY PSEUDOMONAS-AERUGINOSA, HELICOBACTER-PYLORI, CAMPYLOBACTER-JEJUNI, AND HAEMOPHILUS-INFLUENZAE MAY CAUSE FALSE-POSITIVE TITERS OF ANTIBODY TO HELICOBACTER-PYLORI

Cystic fibrosis (CF) patients suffer from many of the gastrointestinal conditions which occur in non-CF individuals, e.g., dyspepsia and pep tic ulceration, These symptoms may be caused by Helicobacter pylori bu t could also be due to either pancreatic insufficiency or the intensiv e antibiotic treatment used in CF patients, Since CF patients chronica lly infected with Pseudomonas aeruginosa produce antibodies against a wide range of antigens, including antigens common to many other bacter ia, e.g., GroEL and lipopolysaccharide, we studied, by the Western blo t (immunoblot) technique, the specificity of immunoglobulin G antibodi es to H, pylori in Danish CF patients chronically infected with P. aer uginosa, CF patients without P. aeruginosa infection but with Haemophi lus influenzae infection, patients with dyspeptic ulcers associated wi th H. pylori, and patients recovering from acute Campylobacter jejuni or Campylobacter coli infection, Sera from CF patients with chronic P, aeruginosa or H. influenzae infection and patients recovering from ac ute C. jejuni infection cross-reacted with H. pylori antigens. A stron g cross-reacting protein antigen at approximately 14 kDa and minor cro ss-reactive antigens at approximately 27, 30, and 60 kDa (the heat sho ck protein GroEL is equivalent to the common antigen of P. aeruginosa) could be demonstrated, The results of this study show that high immun oglobulin G antibody titers against H. pylori in CF patients cannot be regarded as indicating present or past H, pylori infection unless the ir specificity is proven by absorption studies.