| Objective To examine the serum levels of pulmonary surfactant protein-D(SP-D) and Krebs Von den Lungen-6(KL-6) in the patients with systemic sclerosis (SSc) combined with interstitial lung disease (ILD), and to analyze their correlations with the clinical signs, immunological indexes and lung function in search for novel serum diagnostic biomarkers of ILD. Methods From Jan 2013 to Oct 2013, thirty-five cases of SSc patients diagnosed in our hospital were collected. The serum KL-6 and SP-D levels of all research objects, including 15 SSc-non ILD patients, 20 SSc-ILD patients and 19 age- and sex-matched healthy controls, were examined by ELISA. The serum levels of KL-6 and SP-D among the SSc group, the SSc-ILD group, the SSc-non ILD group and the control group were compared, and the correlations between above serological results and pulmonary function indexes were analyzed. Results The serum KL-6 and SP-D levels in the SSc-ILD group were significantly higher than those in the SSc-non ILD and control groups (P<0.05). However, no significant difference was found between those SSc-non ILD patients and healthy controls (P>0.05). In the SSc patients, their pulmonary function results of diffusing capacity of the lung for carbon monoxide (DLCO), forced vital capacity (FVC) and vital capacity (VC) were negatively correlated with the serum KL-6 and SP-D levels. And the SP-D levels were negatively correlated with the IgG and IgM levels, irrelevant to the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and IgA levels. No correlation was found between the KL-6 levels and the ESR, CRP, IgG, IgA and IgM levels. Conclusion The serum KL-6 and SP-D levels of SSc patients combined with ILD increase significantly, and are negatively correlated with the lung function indexes. The serological indexes of serum KL-6 and SP-D levels may be helpful to diagnose and assess the disease severity of those SSc-ILD patients. |
