Cerebrospinal fluid immunoglobulin kappa light chain in clinically isolated syndrome and multiple sclerosis.
BACKGROUND
Oligoclonal bands (OCB) are the most widely used CSF test to support the diagnosis of MS and to predict conversion of clinically isolated syndrome (CIS) to multiple sclerosis (MS). Since OCB tests are based on non-quantitative and difficult to standardise techniques, measurement of immunoglobulin kappa free light chains (KFLC) may represent an easier to use quantitative test.


METHODS
KFLC were measured in CSF and serum of 211 patients using ELISA. These include patients without any inflammatory central nervous system reaction (NIND, n = 77), MS (n = 20), viral CNS infections (V-CNS-I, n = 10), neuroborreliosis (NB, n = 17) and other bacterial CNS infections (B-CNS-I, n = 10). Furthermore a cohort of 77 patients with CIS, including 39 patients that remained CIS over follow-up of two years (CIS-CIS) and 38 patients that developed MS over the same follow-up time (CIS-MS).


RESULTS
CSF-serum ratio of KFLC (Q KFLC) was elevated in all patients with MS, 86.8% of patients with CIS-MS and 61.5% of patients with CIS-CIS. It was significantly elevated in CIS with presence of OCB (p<0.001). Q KFLC significantly correlated with other CSF variables such as CSF leukocyte count (p<0.001, R = 0.46), CSF CXCL13 levels (p<0.001, R = 0.64) and also intrathecal IgG synthesis (p<0.001, R = 0.74) as determined by nephelometry and quotient diagram. OCB were detected in 66.7% of CIS-CIS and in 92.1% of CIS-MS.


CONCLUSIONS
Although the measurement of CSF KFLC is a rapid and quantitative easy to standardize tool, it is almost equal but not superior to OCB with regard to diagnostic sensitivity and specificity in patients with early MS.
Department of Neurology, University of Ulm, Ulm, Germany.
Makbule
M
Senel
Department of Neurology, University of Ulm, Ulm, Germany.
Hayrettin
H
Tumani
Department of Neurology, University of Ulm, Ulm, Germany.
Florian
F
Lauda
Department of Neurology, Wilhelminenspital, Vienna, Austria.
Stefan
S
Presslauer
Department of Neurology, University of Ulm, Ulm, Germany.
Rehaneh
R
Mojib-Yezdani
Department of Neurology, University of Ulm, Ulm, Germany.
Markus
M
Otto
Department of Neurology, University of Ulm, Ulm, Germany.
Johannes
J
Brettschneider
D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000097:blood* / Q000134:cerebrospinal fluid*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood* / Q000134:cerebrospinal fluid*
D007145:Immunoglobulin kappa-Chains