Cystic fibrosis (CF) is associated with the appearance of serum autoantibodies directed against bactericidal/permeability-increasing protein (BPI).
To determine the age-specific seroprevalence rates of anti-BPI-IgG and IgA in a population of patients with CF and to correlate anti-BPI antibody concentrations with microbial respiratory tract colonization and pulmonary function variables at the time of serum sampling and 6 years thereafter.
Determination of BPI antibodies of the IgG and IgA isotypes using a commercial enzyme-linked immunosorbent assay in sera of a CF serum bank of 1992; correlation of anti-BPI antibody concentrations with age, clinical score, pulmonary function variables in 1992 and 1998, total serum immunoglobulin isotype concentrations and respiratory tract colonization withPseudomonas aeruginosaandAspergillusspp.
Seventy-one patients (age in 1992, 14.1 ± 7.5 years) were studied. Reactivities for anti-BPI-IgG and IgA were found in 28 (39%) and 26 (37%) patients, respectively. The seroprevalence of anti-BPI-IgA, but not IgG, increased significantly with age.P. aeruginosacolonization was associated with elevated concentrations of anti-BPI-IgG (P= 0.003) and IgA (P= 0.037). There were significant negative correlations between pulmonary function variables (vital capacity, forced expiratory volume in 1 s) in 1992 and 1998, respectively, and concentrations of anti-BPI-IgG or IgA in a multiple regression analysis. Anti-BPI-IgG, but not IgA, remained significantly associated withP. aeruginosacolonization (P= 0.006) and with reduced vital capacity (P= 0.01) in 1998 after correction for total serum isotype concentration.
Anti-BPI-IgG are strongly associated with concurrentP. aeruginosacolonization and with long term restrictive pulmonary function abnormalities.