Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Aug 22;7(1):58.
doi: 10.1186/s42466-025-00419-7.

Kappa free light chain concentration in serum is reduced after CD20-depletion with ocrelizumab

Franz Felix Konen  1 , Gudrun Mechthild Körner  2 , Martin W Hümmert  1 , Philipp Sebastian Gehring  1 , Philipp Schwenkenbecher  1 , Konstantin Fritz Jendretzky  1 , Sandra Nay  1 , Nora Möhn  1 , Lea Grote-Levi  1 , Kurt-Wolfram Sühs  1 , Elke Voß  3 , Refik Pul  4   5 , Torsten Witte  6 , Thomas Skripuletz  1 , Stefan Gingele  7
Affiliations

Kappa free light chain concentration in serum is reduced after CD20-depletion with ocrelizumab

Franz Felix Konen et al. Neurol Res Pract. .

Abstract

Background: Kappa free light chains (KFLC), a byproduct of immunoglobulin (Ig) synthesis by B-lineage cells, can serve as an indicator for inflammatory activity. In multiple sclerosis (MS), especially the intrathecal KFLC production has gained increasing importance as a biomarker for central nervous system (CNS) inflammation and was included into the proposed 2024 revision of the McDonald criteria. In contrast, studies investigating the significance of KFLC in serum and the effects of disease-modifying therapies (DMT) on KFLC serum concentration in MS are rare. The aim of the present work was to investigate the impact of B cell depletion with ocrelizumab on KFLC concentrations in serum of MS patients and the ability of serum KFLC to monitor disease activity.

Methods: 50 MS patients were included in the present study- 38 with the diagnosis of relapsing MS (RMS) and 12 with diagnosis of primary-progressive MS (PPMS) -, who were treated with ocrelizumab for two years. Serum concentrations of albumin, immunoglobulins and KFLC as well as lymphocyte subsets were determined at baseline and after two years.

Results: Serum Ig and KFLC concentrations were found to be significantly lower after two years of ocrelizumab treatment (mean serum concentrations: KFLC: 9.5 mg/l vs. 7.8 mg/l, p = 0.0003; IgG: 9 g/l vs. 8 g/l, p = 0.0002; IgA: 2 g/l vs. 1.8 g/l, p = 0.0010; IgM: 1.8 g/l vs. 0.7 g/l, p < 0.0001). Serum KFLC concentration did not correlate with clinical and paraclinical parameters of disease activity.

Conclusions: Treatment with ocrelizumab reduces serum KFLC concentration in MS patients. However, serum KFLC concentration is not able to predict disease activity in these MS patients.

Keywords: Biomarker; Kappa free light chains; Multiple sclerosis; Ocrelizumab; Serum.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: The investigation was approved by the Ethics Committee of MHH (8787_BO_K_2019) and followed the rules of the Declaration of Helsinki of 1964 and its later amendments. Informed consent for participation was obtained from all subjects involved in the study. Consent for publication: Informed consent for publication was obtained from all subjects involved in the study. Competing interests: The authors declare no conflict of interest. Outside the submitted work, some authors received honoraria for lectures, travel grants, or research grants.

Figures

Fig. 1
Fig. 1
Comparison of kappa free light chain (KFLC) and immunoglobulin (Ig) G, A, and M concentrations at baseline and two years under ocrelizumab treatment. Depicted are KFLC (A), IgG (B), IgA (C) and IgM (D) concentrations in serum. The level of statistical significance is indicated above the line
Fig. 2
Fig. 2
Correlations of kappa free light chain (KFLC) concentration. Depicted are correlations of serum KFLC concentration with immunoglobulin (Ig) G (A), A (B) and M (C) concentrations and the absolute cell count of CD20+ lymphocytes (D). The level of statistical significance of the linear regression and the correlation are given as well as the coefficient of correlation (ρ)
See this image and copyright information in PMC

References

    1. Hutchison, C. A., Basnayake, K., & Cockwell, P. (2009). Serum free light chain assessment in monoclonal gammopathy and kidney disease. Nature Reviews Nephrology, 5(11), 621–628. 10.1038/nrneph.2009.151 - PubMed
    1. Konen, F. F., Wurster, U., Schwenkenbecher, P., Gerritzen, A., Groß, C. C., Eichhorn, P., Harrer, A., Isenmann, S., Lewczuk, P., Lewerenz, J., Leypoldt, F., Otto, M., Regeniter, A., Roskos, M., Ruprecht, K., Spreer, A., Strik, H., Uhr, M., Wick, M., Wildemann, B., Wiltfang, J., Zimmermann, T., Hannich, M., Khalil, M., Tumani, H., Süße, M., Skripuletz, T., & German Society for Cerebrospinal Fluid Diagnostics and Clinical Neurochemistry (DGLN e.V.). (2025). Oligoclonal bands and kappa free light chains: Competing parameters or complementary biomarkers? Autoimmunity Reviews, 24(5), 103765. 10.1016/j.autrev.2025.103765 - PubMed
    1. Gottenberg, J. E., Aucouturier, F., Goetz, J., Sordet, C., Jahn, I., Busson, M., Cayuela, J. M., Sibilia, J., & Mariette, X. (2007). Serum Immunoglobulin free light chain assessment in rheumatoid arthritis and primary sjogren’s syndrome. Annals of the Rheumatic Diseases, 66(1), 23–27. 10.1136/ard.2006.052159 - PMC - PubMed
    1. Ye, Y., Li, S. L., Xie, M., Jiang, P., Liu, K. G., & Li, Y. J. (2013). Judging disease activity in rheumatoid arthritis by serum free kappa and lambda light chain levels. The Kaohsiung Journal of Medical Sciences, 29(10), 547–553. 10.1016/j.kjms.2013.01.013 - PMC - PubMed
    1. Kaplan, B., Livneh, A., & Sela, B. A. (2011). Immunoglobulin free light chain dimers in human diseases. TheScientificWorldJournal, 11, 726–735. 10.1100/tsw.2011.65 - PMC - PubMed

LinkOut - more resources