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Free Light Chains and Intrathecal B Cells Activity in Multiple Sclerosis: A Prospective Study and Meta-Analysis
Gabriella Passerini1, Gloria Dalla Costa2, Francesca Sangalli2
1Department of Laboratory Medicine, San Raffaele Hospital, Milan, Italy.
Abstract:
Background. The presence of CSF oligoclonal bands (OBs) is an independent prognostic factor for multiple sclerosis (MS), but the difficulties in the standardization of the test and the interlaboratory variation in reporting have contributed to its limited use in the diagnosis of the disease. Standard nephelometric assays to measure free light chains (FLC) levels have been recently developed and the test may improve the detection of intrathecal B cells activity. Methods. The presence of OBs, kappa and lambda FLC levels, and standard indices of intrathecal inflammation were assessed in 100 consecutive patients, including patients with MS, clinically isolated syndromes (CIS), other inflammatory diseases of the CNS, and other noninflammatory diseases. Results. Both KFLC and LFLC correlated strongly with the presence of OCBs and with all common tests for intrathecal inflammation (p < 0.001 for all comparisons). KFLC and LFLC were significantly different in patients with MS and CIS compared to the other groups (p < 0.001 and p < 0.001, resp.) and had a better diagnostic accuracy than all the other tests (area under the curve 82.3 % for KFLC index and 79.3 % for LFLC index). Conclusion. Nephelometric assays for KFLC in CSF reliably detect intrathecal immunoglobulin synthesis and discriminate MS patients.
Insights
Free light chain (FLC) assays in cerebrospinal fluid reliably detect intrathecal inflammation in multiple sclerosis (MS). This method shows improved diagnostic accuracy compared to traditional oligoclonal band tests for MS and clinically isolated syndromes.
Area of Science:
- Neurology
- Immunology
- Clinical Chemistry
Background:
- Oligoclonal bands (OBs) in cerebrospinal fluid (CSF) are prognostic in multiple sclerosis (MS).
- Standardization issues and interlaboratory variations limit the diagnostic utility of OB testing.
- Nephelometric assays for free light chains (FLC) offer a potential improvement for detecting B-cell activity.
Purpose of the Study:
- To evaluate the diagnostic accuracy of CSF kappa and lambda FLC levels in patients with MS and related neurological conditions.
- To compare the efficacy of FLC assays with standard tests for intrathecal inflammation, including OB detection.
Main Methods:
- Assessed CSF oligoclonal bands (OBs), kappa FLC (KFLC), and lambda FLC (LFLC) in 100 consecutive patients.
- Included patients with MS, clinically isolated syndromes (CIS), other CNS inflammatory diseases, and non-inflammatory diseases.
- Compared FLC levels and OB presence with standard intrathecal inflammation markers.
Main Results:
- Both KFLC and LFLC strongly correlated with OBs and other intrathecal inflammation markers (p < 0.001).
- KFLC and LFLC levels were significantly elevated in MS and CIS patients compared to other groups (p < 0.001).
- KFLC and LFLC indices demonstrated superior diagnostic accuracy (AUC 82.3% and 79.3%, respectively) over other tests.
Conclusions:
- Nephelometric assays for CSF KFLC reliably detect intrathecal immunoglobulin synthesis.
- These assays effectively discriminate between MS patients and those with other neurological conditions.
- FLC measurement presents a more accurate and standardized approach for diagnosing MS.
