Verstappen GM, et al. - Researchers evaluated whether serum free light chains (FLCs) can contribute to classification, mucosa-associated lymphoid tissue (MALT) lymphoma detection, monitoring of disease activity and treatment response in primary Sjogren’s syndrome (pSS). They noted an elevation of serum FLCs in pSS, and for the presence of MALT lymphoma, abnormal FLCκ/FLCλ ratios may be indicative. For systemic disease activity and monitoring treatment responses, FLC levels could be used as a biomarker. Findings suggested senstivity of FLCs to change and have more favorable kinetics than IgG.