Surfactant protein D in serum from patients with allergic bronchopulmonary aspergillosis

Surfactant protein D (SP-D) interacts with Aspergillus fumigatus and is strongly increased in the lavage from animals with acute allergic reactions to the fungus, suggesting a central role for SP-D. As the course of cystic fibrosis (CF) is often complicated by an allergic bronchopulmonary aspergillosis (ABPA), the authors hypothesised that SP-D may also be increased in serum during an ABPA, potentially assisting in its diagnosis and follow-up. In 22 patients with CF (11 with ABPA, 11 matched without ABPA) and 19 control patients without a pulmonary disease, SP-D concentrations in serum were assessed by an enzyme immunoassay. Serum SP-D in CF patients (130 +/- 16 ng x mL(-1) (mean +/- SEM)) was significantly higher than in the controls without lung disease (66 +/- 8 ng x mL(-1)). During the whole ABPA-episode, SP-D level did not change significantly, despite large changes of total serum immunoglobulin E. There was a clear negative correlation between SP-D concentration and overall lung function, i.e. forced expiratory volume in one second and forced vital capacity. Serum level of surfactant protein D may be of value to follow pulmonary function and lung injury in cystic fibrosis patients. Surfactant protein D serum levels are not helpful for the diagnosis and follow-up of an allergic bronchopulmonary aspergillosis episode, contrary to what was expected from animal experiments.