[Screening for serum specific biomarkers in patients with primary Sjögren's syndrome and interstitial lung disease using proteomic fingerprint techniques].

OBJECTIVE: To detect the serum protein biomarkers and establish a diagnostic model for primary Sjögren's syndrome (pSS) with interstitial lung disease (ILD).

METHODS: Serum samples from 69 patients with pSS were prepared with WCX magnetic beads, and analyzed on PBS II-C mass spectrometer reader. Biomarker Wizard software was used to detect protein peaks and potential difference between the patients with pSS-ILD and with non-ILD. The model was developed by Biomarker Patterns software.

RESULTS: Totally 7 discriminative mass-to-charge (m/z) ratios were identified to be related with pSS-ILD (P<0.05). Among these, the m/z peaks at 3 778.3, 3 318.3 and 2 236.6 were used to construct a diagnostic model. The sensitivity and specificity of the model were 93.1% and 87.5%, respectively. In a testing set, the sensitivity and specificity of the model were 84.0% and 85.7%, respectively.

CONCLUSION: The potential protein biomarkers for pSS-ILD are discovered in the serum by MALDI-TOF-MS combined with WCX magnetic beads. The diagnostic pattern combining 3 778.3, 3 318.3 and 2 236.6 m/z protein peaks can discriminate pSS-ILD and non-ILD.