Author Of 1 Presentation
P0246 - Clinical relevance of Kappa Free Light Chain index to evaluate intrathecal IgG synthesis: prospective study compared to oligoclobal bands (ID 1489)
Abstract
Background
An early and specific diagnosis of MS leads to an early treatment to better control the disease and its progression. Importance of immunoglobulin G (Ig G) synthesis in cerebrospinal fluid (CSF) has been re-emphasized for multiple sclerosis (MS) diagnosis since Mc Donald 2017 criteria. This synthesis is currently measured through the oligoclonal bands (OCB) using isoelectric focusing (ISE) technic, which is a time-consuming, expensive and may be difficult to interpret. Measurement of kappa free light chain (KFLC) in CSF and serum could offer a faster, standardized and less expensive way to evaluate the intrathecal Ig G synthesis.
Objectives
Primary objective is to test the relevance of KFLC index measurement in the diagnosis of MS compared with OCB measurement, using sensitivity and specificity of KFLC index in the diagnosis of MS. Secondary objective is to calculate a KFLC index threshold defining the IgG intrathecal synthesis. Methods: This is a prospective study including consecutively patients admitted in MS centre and/or other department of neurology at Lille University Hospital, who needed to undergo CSF lumbar puncture for CSF analysis. OCB and KFLC indexes were performed for all of them. KFLC index measured by turbidimetric assay on a SPAplus@ (The Binding Site Birmingham, UK).
Methods
We plan to include 250 patients in the study. Preliminary results concern 94 patients: 28 MS patients fulfilling 2017 MS criteria, 9 patients presenting CIS, 15 patients having other inflammatory disease (OID), 42 patients having non inflammatory disease (NOID). All MS patients who had OCB in CSF presented a KFLC index with a median value of 104.9 [6.43-649.7]; 3 MS patients who did not have OCB in CSF presented a median KFLC of 21.6 [10.1-23.4]. Height OID patients and 2 NOID patients had OCB in CSF; OID patients had a median KFLC value of 3.71 [1.7-600.8] and NOID of 3.2 [1.1-162.2].
Results
We plan to include 250 patients in the study. Preliminary results concern 94 patients: 28 MS patients fulfilling 2017 MS criteria, 9 patients presenting CIS, 15 patients having other inflammatory disease (OID), 42 patients having non inflammatory disease (NOID). All MS patients who had OCB in CSF presented a KFLC index with a median value of 104.9 [6.43-649.7]; 3 MS patients who did not have OCB in CSF presented a median KFLC of 21.6 [10.1-23.4]. Height OID patients and 2 NOID patients had OCB in CSF; OID patients had a median KFLC value of 3.71 [1.7-600.8] and NOID of 3.2 [1.1-162.2].
Conclusions
KFLC index seems to be more sensitive than OCB in the diagnosis of MS. Sensitivity, specificity and threshold of KFLC index defining the intrathecal synthesis will be evaluated with the next patients studied.