Antibody response to Burkholderia cepacia in patients with cystic fibrosiscolonized with Burkholderia cepacia and Pseudomonas aeruginosa

Introduction: This study was designed to determine the relationship between formation of serum antibodies to lipopolysaccharide (LPS) core antigen of Burkholderia cepacia and pulmonary colonization with B, cepacia and Pseudom onas aeruginosa in patients with cystic fibrosis (CF), and to define if an enhanced host humoral immune response to B. cepacia was related to a poor c linical outcome, Methods: Serum IgG to B, cepacia LPS core antigen was measured in adult cys tic fibrosis patients colonized with B, cepacia and P. aeruginosa, and seri al titres were measured in 13 B. cepacia and 41 P. aeruginosa colonized pat ients followed prospectively over 18 months, Results: The median B. cepacia antibody titre was significantly greater in the patients colonized with B, cepacia compared to those colonized with P. aeruginosa, a group which grew B. cepacia intermittently from their sputum, and nine healthy controls, The median antibody titre at recruitment into t he study was significantly greater in patients who later went into exacerba tions compared with those who remained clinically stable, but there was no difference between B, cepacia antibody titres in patients who died and thos e who survived the study duration, Discussion: The degree of overlap of serum IgG levels to B. cepacia LPS cor e antigen in cystic fibrosis patients colonized with B, cepacia and P. aeru ginosa does not allow this antibody to be used in a clinical context to def ine infection status, The magnitude of the humoral response to B, cepacia m ay influence occurrence of pulmonary exacerbations, but a more exuberant hu moral immune response to B. cepacia core LPS is not the mechanism by which pulmonary deterioration occurs, (C) 2000 The British Infection Society.