Lanteri et al.  studied the value of the combined total of κ and λ concentrations (cFLC, determined by Combylite® [Section 30.7]) as a biomarker of disease activity and severity in 134 SSc patients. At baseline, SSc patients had significantly higher cFLC concentrations than controls (mean 24.0 mg/L vs. 17.5 mg/L, p=0.0002). The authors noted a significant correlation between cFLC concentrations with disease activity and interstitial lung disease, but only the association with lung disease remained significant on multivariate analysis. Bosello et al.  measured κ and λ sFLCs individually, and found that SSc patients had higher k sFLC than controls, whilst l sFLCs were comparable. This resulted in an abnormal sFLC ratio in around 30% of individuals. Similar findings reported by Hoffmann et al. . Bosello at al.  also reported that sFLC concentrations correlated with disease activity and the presence of restrictive lung disease.