Systemic sclerosis (SSc) is a chronic autoimmune disease of the connective tissue. Bosello et al.  measured κ and λ sFLCs in 65 SSc patients, and found that SSc patients had higher κ sFLC than controls (n=20) (mean κFLC = 20.4 mg/L vs 9.4 mg/L respectively, p<0.001), whilst λ sFLCs were comparable. This resulted in an abnormal sFLC ratio in around 30% of individuals. SSc patients had higher total sFLC concentrations than controls. Similar findings were reported by Hoffmann et al. . Bosello at al.  also reported that sFLC concentrations correlated with disease activity and the presence of restrictive lung disease.