A study of surfactant protein-D serum levels in patients with idiopathic pulmonary fibrosis

Abstract

Background Several and most recent studies have shown that idiopathic pulmonary fibrosis (IPF) has a high mortality rate and the therapy used is almost noneffective. Any serum biomarker that predicts better clinical outcomes would be useful to disease stages, prognosis, and need for other and more aggressive therapy, and may be beneficial to the patients in clinical trials. This study aimed to measure the level of surfactant protein-D (SP-D) in the serum of patients with IPF, its relation with clinical manifestations, and its role in predicting the outcome of the patients (prognosis, progression, or regression of the disease, and quality of life) on the basis of assessment of quality of life using the Arabic version of St. George’s respiratory questionnaire. Participants and methods This study included 35 IPF patients and 15 healthy nonsmokers volunteers. Serum level of SP-D was measured in the serum of patients and control participants, relating their levels with the measurements of arterial blood gases, spirometry functions [forced vital capacity (FVC%) of predicted, forced expiratory volume in 1 s (FEV1%) of predicted, and FEV1/FVC%], and high-resolution computed tomography. Results Serum level of SP-D was significantly increased in IPF patients compared with the control participants; also, their levels were significantly increased in IPF smokers compared with nonsmokers and ex-smoker IPF patients. SP-D showed statistically significant negative correlations with PaO2, but it showed statistically significant positive correlations with the FEV1/FVC% actual value. Conclusion SP-D level is higher in IPF patients, and it also increases in smoker IPF patients compared to nonsmokers and ex-smokers.

Keywords

• fibrosis
• idiopathic
• surfactant protein-D