OBJECTIVETo study the variation and clinical significance of serum levels of surfactant proteins A (SP-A) and D (SP-D) among children with different degrees of bronchiolitis.

METHODSSeventy children with bronchiolitis were divided into acute (n=42) and recovery phase groups (n=28). According to the severity of symptoms, the acute phase group was further divided into severe (n=12) and mild subgroups (n=30). Another 26 children who were hospitalized in the same period due to non-infectious diseases and had not undergone surgery were used as the control group. Competitive enzyme-linked immunosorbent assay was performed to measure serum levels of SP-A and SP-D in each group.

RESULTSThe acute phase group had significantly higher serum levels of SP-A and SP-D compared with the recovery phase (P<0.01) and control groups (P<0.01). Compared with the control group, the recovery phase group had elevated levels of SP-A and SP-D (P<0.01). Within the acute phase group, serum levels of SP-A and SP-D in the severe subgroup were significantly higher than in the mild subgroup (P<0.01).

CONCLUSIONSSerum levels of SP-A and SP-D are significantly elevated in children with acute bronchiolitis, and severe cases have higher serum levels of SP-A and SP-D than mild cases. Even after the relief of clinical symptoms, serum levels of SP-A and SP-D remain high. These findings suggest that serum levels of SP-A and SP-D might be useful biomarkers for evaluating the severity of bronchiolitis among children.