SFTPD and interstitial lung disease: A recent study of serum samples from a group of patients with SSc from Paris, France, and Oslo, Norway, found that surfactant protein D (SP-D) might be a potential diagnostic biomarker for ILD associated with SSc, while Krebs von den Lungen 6 glycoprotein (KL-6) can be used to assess the severity of pulmonary fibrosis.