Serum SP-D levels as a biomarker of lung injury in respiratory syncytial virus bronchiolitis.

To evaluate whether SP-D concentration is a useful biomarker of the severity of respiratory syncytial virus (RSV) bronchiolitis, we determined SP-D concentrations in patients with RSV bronchiolitis with or without chronic heart disease. We enrolled 52 patients who had been diagnosed with RSV bronchiolitis and required admission to the hospital at the Department of Pediatrics of Fukushima Medical University School of Medicine from 2004 through 2005. These patients were divided into two groups: Group 1 consisted of patients without any underlying disease and Group 2 consisted of patients with chronic heart disease. These patients were assigned to one of three categories. Stage A consisted of patients without oxygen dosage, Stage B of patients who required oxygen dosage, and Stage C of patients required artificial respiration. We evaluated baseline characteristics, clinical features, and serum SP-D concentration in Group 1, Group 2, and a control group (healthy infants without infection). Mean serum SP-D concentrations in patients with RSV bronchiolitis were higher than those in the control group (125.8 ± 49.3 and 44.2 ± 20.1 ng/ml, respectively). Mean serum SP-D concentration was also higher in Group 2 than in Group 1 patients (160.4 ± 56.4 and 112.3 ± 39.4 ng/ml, respectively). Mean serum SP-D concentrations were higher in Stage C than in Stages A or B patients, and mean serum SP-D concentrations were higher in Stage B than in Stage A. These findings suggest that serum SP-D is associated with the severity of RSV bronchiolitis and that it may be a useful biomarker for the severity of RSV bronchiolitis.