Sandhya P, Kabeerdoss J, Christudoss P, et al. - In this study testing a hypothesis, it was revealed that salivary FLCλ (free light chain) and salivary immunoglobulin (IgG) were significantly different between primary Sjögren's syndrome (pSS) and control groups and may serve as potential non-invasive biomarkers in pSS.

• This cross-sectional study involved 78 patients with pSS, 76 healthy controls and 62 disease controls, to investigate if salivary FLCs and salivary Igs could represent salivary gland inflammation and thus, serve as biomarkers in pSS.

• The pSS group had significantly higher serum FLCκ and FLCλ, salivary FLCλ, serum and salivary IgG, salivary IgM, vs controls.

• For salivary FLCλ, serum FLCκ, serum and salivary IgG, the generated areas under the curve were 0.75, 0.72, 0.78 and 0.77, respectively.

• In regression analysis, salivary FLCκ, salivary FLCλ and salivary IgG were shown to be related to positive salivary gland histopathology.

• Lower values of salivary parameters were noted in relation to use of immunosuppressants and glucocorticoids.