Serum immunoglobulin free light chains are sensitive biomarkers for monitoring disease activity and treatment response in primary Sjogren's syndrome

Verstappen, G. M., Moerman, R., van Nimwegen, J. F., van Ginkel, M. S., Bijzet, J., Mossel, E., Vissink, A., Hazenberg, B. P. C., Arends, S., Kroese, F. G. M. & Bootsma, H., 1-Oct-2018, In : Rheumatology. 57, 10, p. 1812-1821 10 p.

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  • Serum immunoglobulin free light chains are sensitive biomarkers for monitoring disease activity and treatment response in primary Sjögren’s syndrome

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Objectives. Serum immunoglobulin free light chains (FLCs) are frequently elevated in B-cell-mediated autoimmune diseases, including primary SS (pSS). The objective of this study was to assess if serum FLCs can contribute to classification, mucosa-associated lymphoid tissue (MALT) lymphoma detection, monitoring of disease activity and treatment response in pSS.

Methods. Serum samples of 100 consecutive patients suspected of pSS were included. Forty-five patients fulfilled ACR-EULAR criteria for pSS. Additionally, samples of 17 pSS patients with MALT lymphoma and longitudinal samples of pSS patients treated with rituximab (n = 20), placebo (n = 10) or abatacept (n = 15) were included. Serum FLC kappa/FLC lambda. was measured by nephelometry or turbidimetry.

Results. At diagnosis, FLC kappa and FLC lambda serum levels were significantly higher in pSS compared with non-SS sicca patients. The FLC kappa/FLC lambda ratio was abnormal in 11% of pSS patients. In established MALT-pSS patients, without recent rituximab treatment (n = 12), 50% had abnormal FLC kappa/FLC lambda ratios. FLC measurement had no additional value for pSS classification, compared with IgG and anti-SSA. FLC levels correlated significantly with systemic disease activity, assessed by EULAR SS Disease Activity Index (ESSDAI) and clinical ESSDAI, both cross-sectionally and longitudinally following treatment. Treatment with rituximab or abatacept significantly lowered FLC levels. FLCs show a large sensitivity to change and relative changes induced by treatment were higher compared with IgG.

Conclusion. Serum FLCs are elevated in pSS, and abnormal FLC kappa/FLC lambda. ratios may be indicative for the presence of MALT lymhoma. FLC levels can be used as a biomarker for systemic disease activity and monitoring treatment responses. FLCs are sensitive to change and have more favorable kinetics than IgG.

Original languageEnglish
Pages (from-to)1812-1821
Number of pages10
Issue number10
Early online date2-Jul-2018
Publication statusPublished - 1-Oct-2018


  • Sjogren's syndrome, immunoglobulin free light chain, lymphoma, B cells, plasma cells, disease activity, biomarker, biologic therapies, rituximab, abatacept, SYSTEMIC-LUPUS-ERYTHEMATOSUS, LYMPHOID-TISSUE LYMPHOMA, B-CELL HYPERACTIVITY, MONOCLONAL GAMMOPATHY, RITUXIMAB TREATMENT, ABATACEPT TREATMENT, RHEUMATOID-FACTOR, CONTROLLED-TRIAL, PATHOGENESIS, MARKER

ID: 62875204