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Pulmonary surfactant protein D in sera and bronchoalveolar lavage fluids.
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1995
Year
AsthmaPulmonary SurfactantInflammatory Lung DiseaseAdvanced Lung DiseaseLung InflammationImmunologyPathologyPulmonary Alveolar ProteinosisEnzyme-linked Immunosorbent AssaySerum Sp-d LevelsLung DepositionAutoimmune DiseasePulmonary FibrosisPulmonary MedicinePulmonary DiseasePulmonary PhysiologyBronchoalveolar Lavage FluidsDisease ActivityMedicine
Pulmonary surfactant protein D (SP‑D) is a 43‑kDa hydrophilic glycoprotein of the C‑type lectin family, related to mannose‑binding proteins and surfactant protein A. The study aimed to quantify SP‑D levels in serum and bronchoalveolar lavage fluids of patients with lung diseases using an ELISA based on recombinant SP‑D. Monoclonal antibodies against human SP‑D were generated and employed in a newly developed ELISA to measure SP‑D concentrations. Serum SP‑D was markedly elevated in idiopathic pulmonary fibrosis, interstitial pneumonia with collagen disease, and pulmonary alveolar proteinosis—5.1‑, 7.2‑, and 7.0‑fold increases, respectively, with 91.5%, 81.3%, and 100% of patients exceeding the cut‑off—reflecting disease activity or severity, while high BAL SP‑D was observed only in PAP, supporting its use as a diagnostic and prognostic marker.
Pulmonary surfactant protein D (SP-D) is a hydrophilic glycoprotein with a reduced molecular mass of 43 kDa and a member of the C-type lectin superfamily, along with mannose-binding proteins and surfactant protein A (SP-A). We have recently prepared monoclonal antibodies against human SP-D and developed an enzyme-linked immunosorbent assay (ELISA). In this study, the levels of SP-D in sera and bronchoalveolar lavage (BAL) fluids of patients with lung diseases were determined by ELISA, using human recombinant SP-D as a standard. We demonstrated that the concentrations of SP-D in sera are prominently increased in patients with idiopathic pulmonary fibrosis (IPF), interstitial pneumonia with collagen disease (IPCD), and pulmonary alveolar proteinosis (PAP). Patients with IPF, IPCD, and PAP exhibited levels of serum SP-D 5.1-fold, 7.2-fold, and 7.0-fold, respectively, of those in healthy volunteers; 91.5% of the patients with IPF, 81.3% with IPCD, and 100% with PAP exhibited serum SP-D levels that exceeded the cut-off value (mean + 2 SD of control value). Serum SP-D levels appeared to reflect the disease activity of IPF and IPCD and the disease severity of PAP. High levels of SP-D in BAL fluids were shown in patients with PAP, but not with IPF and IPCD. We conclude that measurement of SP-D in sera can provide an easily identifiable and useful clinical marker for the diagnosis of IPF, IPCD, and PAP, and can predict the disease activity of IPF and IPCD and the disease severity of PAP.