Free kappa and lambda light chain levels in the cerebrospinal fluid of patients with multiple sclerosis and other neurological diseases

Free kappa and lambda light chains were assayed by particle-counting immunoassay in cerebrospinal fluid (CSF) from patients with various neurological disorders. Detection limits were 25 and 50 ng/ml, respectively. Values of free kappa chain were higher than 50 ng/ml (upper reference limit) in 155 of 191 (81%) multiple sclerosis (MS) patients, in 100 of 168 (60%) patients with central nervous system (CNS) infections but in 41 of 217 (19%) patients with other neurological disorders. Free kappa chains were also assayed in 273 matched sera. The mean concentration in the control group (1.58 micrograms/ml; SD: 0.41) did not differ significantly from those in MS sera (1.63 micrograms/ml; SD: 0.43). The free kappa chain index was increased in 86% of MS patients and in 40% of patients with CNS infections. Regarding free lambda chains, CSF values were higher than 240 ng/ml (upper reference limit) in most neurological disorders (50-100%). However, the use of a lambda chain index increased the specificity of the assay as this index was higher than the upper reference value in 86% of MS patients and in only 23% of patients with infectious diseases. In MS, high levels of free kappa and lambda indices correlated significantly (P less than 0.01) with either the presence of oligoclonal bands or a high IgG index. Local synthesis of free light chains is an additional marker of an ongoing immune response within the CNS, especially in MS.     

Relative diagnostic value of cerebrospinal fluid kappa chains in MS: comparison with other immunoglobulin tests

We used receiver operating characteristic (ROC) curve analysis to determine the relative performance of different CSF IgG parameters as diagnostic markers for multiple sclerosis. We quantitated CSF and serum IgG and albumin to determine an IgG albumin ratio, IgG index, Tourtellotte's synthesis rate, and Schuller's formula; CSF free kappa light chains were measured by radioimmunoassay. We compared a group of patients with clinically definite MS with a group of patients with a variety of other neurologic diseases. Tourtellotte's formula, IgG albumin ratio, IgG index, and free kappa chains distinguished the MS group from the comparative group of patients. ROC curve analysis demonstrated that CSF free kappa light chains were more closely linked to MS than the other measures. Multiple logistic regression analysis demonstrated no advantage of adding any single IgG measure or combination of measures to free kappa light chain analysis. Our results strongly suggest that free kappa light chains in CSF are the single best quantitative assay to support a clinical diagnosis of MS.     

Free kappa light chains in multiple sclerosis spinal fluid

Based on prior reports of free light chains of immunoglobulin G (IgG) in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS), we quantitated free kappa and lambda chains and whole IgG concentrations using sensitive and specific radioimmunoassays (RIAs). The RIA for free kappa chains had a sensitivity of 0.25 micrograms/ml and was capable of specifically measuring free kappa chains in whole CSF or serum even in the presence of a 4-log excess of whole IgG. By RIA, free kappa chains were detected in CSF samples from 33 (84%) of 39 MS patients but in only 1 (2.4%) of 42 controls. The control patients included 10 with noninfectious inflammatory diseases and 9 with central nervous system infections. The concentration of free kappa chains in the CSF of the MS patients was 1.40 +/- 1.21 micrograms/ml. Free kappa chains were concentrated in the CSF 71- to 120-fold relative to reference proteins. In contrast, increased levels of free lambda chains or of whole IgG were nonspecific; abnormalities were seen in controls with infections or inflammatory diseases as often as in MS patients. These studies suggest that the measurement of free kappa light chains may have important diagnostic usefulness, since the specificity of the finding for MS appears to be high.     

Oligoclonal free kappa and lambda bands in the cerebrospinal fluid of patients with multiple sclerosis and other neurological diseases. An immunoaffinity-mediated capillary blot study.

We describe an affinity-mediated capillary blotting technique for the detection of free kappa or lambda light chains in native cerebrospinal fluid (CSF) after isoelectric focusing in agarose gel. Interferences by light chains bound to immunoglobulins were carefully excluded. An absolute amount of 20-50 ng of free kappa or lambda Bence-Jones proteins were detectable by this method, under the form of several discrete bands with isoelectric points between 5 and 8.5. No free light chains were observed in CSF and sera from patients without neurological disorders (n = 26). Such bands were present in most CSF samples in the case of central nervous system (CNS) infections, except in aseptic meningitis. In a group of 48 multiple sclerosis (MS) patients, 44 (92%) displayed oligoclonal free kappa bands restricted to the CSF; oligoclonal IgG bands were observed in 40 cases, and oligoclonal free lambda bands in 33. In this group, the presence of CSF free light chain bands was highly correlated with their absolute levels (p less than 0.001). In other neurological diseases (n = 44), oligoclonal free kappa and free lambda bands were detected much more rarely, in seven (16%) and four (9%) cases respectively. Surprisingly, the CSF from three unrelated patients with Huntington's disease (out of five tested) contained both oligoclonal IgG and free kappa bands.     

Multiple sclerosis: free light chains in cerebrospinal fluid

We found free light chains in the CSF of 18 MS patients, but not in any of 14 patients with other neurologic disease. CSF from all MS patients contained kappa and lambda chain dimers, less frequently contained light chain monomers, and never contained free gamma heavy chains. Light chains were not detected in matched serum samples. CSF from MS patients did not release free light chains from whole IgG in CSF of controls. The findings suggest that these free light chains originate in plasma cells, not from degradation of whole IgG.     

Immunoglobulin class and light chain type of oligoclonal bands in CSF in multiple sclerosis determined by agarose gel electrophoresis and immunofixation.

Agarose gel electrophoresis and immunofixation of CSF and serum from 39 patients with multiple sclerosis (MS) revealed oligoclonal IgG in the CSF in all cases and oligoclonal IgA and IgM in 1 patient each. IgG kappa bands only were found in 10 patients, while no patient had IgG lambda bands alone. IgG kappa bands predominated in 20 patients and IgG lambda bands in 5, while 4 patients had the same number of IgG kappa and IgG lambda bands. Twenty-seven patients also displayed IgG bands with kappa and lambda present simultaneously. Bands of free lambda chains were found in 7 patients, while free kappa chain bands were not seen. One or 2 faint IgG bands in 4 patients constituted the only serum abnormality. In 4 additional MS patients selected on the basis of normal findings on agarose gel electrophoresis of the CSF, immunofixation did not reveal oligoclonal Ig, while isoelectric focusing showed bands in 1. Immunofixation is recommended for proving the presence of oligoclonal Ig in CSF and for characterizing oligoclonal Ig into classes and types of light chains.     

Intrathecal synthesis of free immunoglobulin light chains and IgM in initial multiple sclerosis

We studied the intrathecal synthesis of free kappa, free lambda immunoglobulin light chains and of IgM in 33 consecutive patients with possible or probable MS at the time of their first diagnosis. Nineteen patients presented free kappa or lambda light chain bands in CSF after agarose isoelectric focusing, protein transfer to nitrocellulose and immunostaining with specific antisera. Nineteen patients had increased CSF levels of free kappa light chains as measured with a competitive ELISA. Fourteen had an increased IgM index, as evaluated with a sandwich ELISA. Twenty-six patients displayed CSF oligoclonal IgG bands in CSF and 25 had cerebral magnetic resonance imaging lesions suggestive of MS. The local production of free immunoglobulin light chains and IgM is often detected in the CSF of patients with early MS.     

Predominance of oligoclonal IgG type lambda in CSF in aseptic meningitis.

Oligoclonal immunoglobulins (Ig) demonstrble as bands by agarose-gel electrophoresis of CSF were characterized in ten patients with aseptic meningitis. Oligoclonal CSF IgG was found in all patients, IgM was found in two. The oligoclonal Ig was more often of lambda light-chain type than of kappa type. In four patients, oligoclonal Ig bands contained kappa and lambda light chains simultaneously. In two patients, bands consisting of free lambda light chains were found. On repeated investigations more than one year later in three cases, the oligoclonal IgG was of the same light-chain type. The immune response within the CNS in aseptic meningitis seems to be dominated by synthesis of IgG with lambda light chains.     

Kappa light chain predominance in serum and cerebrospinal fluid from human immunodeficiency virus type 1 (HIV-1)-infected patients

We measured kappa/lambda light chain ratios of Ig and IgG in 41 serum and 34 cerebrospinal fluid (CSF) samples from 47 patients at different clinical stages of human immunodeficiency virus type 1 (HIV-1) infection and in serum and CSF samples from control subjects. Both ratios were more elevated in HIV-1 seropositive subjects than controls. The elevation was more evident in samples from asymptomatic seropositive patients (ASP) than those from patients with acquired immunodeficiency syndrome (AIDS). In addition, there was a statistically significant elevation of Ig kappa/lambda ratios in ASP CSF compared to serum. We also delineated the light chain composition of oligoclonal IgG bands (OCB) by isoelectric focusing followed by immunofixation in CSF and serum samples from selected ASP and patients with AIDS who had neurological involvement. Five of six AIDS and all seven ASP samples had IgG OCB exclusively or predominantly of the kappa type. Four IgG OCB of the lambda type and one free lambda chain band were seen in CSF from a pediatric AIDS patient. The presence of an abnormally elevated kappa/lambda ratio correlated with the presence of IgG kappa OCB (p less than 0.02). We conclude that HIV-1 infection is associated with a kappa light chain predominance and with OCB mainly composed of kappa light chains.     

Immunoglobulin class and light chain type of oligoclonal bands in CSF in children with CNS infectious diseases

Agarose gel electrophoresis and immunofixation of CSF and serum from 16 patients aged from 1 day to 13 years with CNS infectious diseases (5 with purulent meningitis, 5 with aseptic meningitis, 4 with acute encephalitis, 1 with subdural empyema and 1 with SSPE) revealed oligoclonal IgG bands in 10 cases. In 4 cases, a high CSF/serum albumin ratio was recognized without an increase of IgG-index, probably representing a systemic immune response. Neither IgA nor IgM bands were recognized. IgG light chain was examined in 7 cases and IgG kappa bands predominated in 6 cases. IgG lambda bands predominance presented in only one case. Free IgG kappa or lambda chain was not found. These results suggested that the measurement of not only IgG-index but oligoclonal bands may have a diagnostic usefulness to know about local production of immunoglobulins in CSF.     

Detection of oligoclonal free kappa chains in the absence of oligoclonal IgG in the CSF of patients with suspected multiple sclerosis

BACKGROUND: Oligoclonal free kappa bands are present as frequently as oligoclonal IgG bands in the cerebrospinal fluid (CSF) from patients with definite multiple sclerosis (MS) and can even occur in the absence of oligoclonal IgG. As such, they too are markers of an ongoing intrathecal immune process. OBJECTIVES: To determine how frequently oligoclonal free kappa bands are detectable in the CSF from patients with clinical signs and symptoms suggestive of MS in the absence of CSF restricted oligoclonal IgG. METHODS: An immunoaffinity mediated immunoblotting technique specific for free kappa chains was used, after isoelectric focusing of paired CSF and serum samples from 33 patients with clinical signs and symptoms suggestive of MS but without CSF oligoclonal IgG. CSF data were correlated with MRI results in the context of the new diagnostic criteria from McDonald et al. RESULTS: Eighteen CSF samples contained oligoclonal free kappa bands (54%), mainly from patients with motor dysfunction (83%) and optic neuritis (64%). All patients with a positive MRI according to Barkhof's criteria (n = 6) had free kappa bands in their CSF. CONCLUSIONS: (1) Oligoclonal free kappa bands in the CSF are related to the dissemination of MS lesions; (2) such bands should be looked for in oligoclonal IgG negative CSF, and (3) the presence of free kappa bands in the CSF may be a substitute for oligoclonal IgG in the McDonald's criteria for diagnosis of MS.     

Free light chains in the CSF in multiple sclerosis

Summary The presence of free light chains (FLC) was investigated in 32 patients with clinically definite or laboratory supported definite multiple sclerosis (MS), 2 patients with neurosyphilis and 10 normal controls. The detection of FLC in unconcentrated cerebrospinal fluid (CSF) was performed by means of agarose isoelectric focusing, followed by transfer of proteins to nitrocellulose membranes, double immunofixation, avidin-biotin amplification and peroxidase staining. Bands due to FLC were clearly demonstrated in the CSF of 28 MS patients; 3 of them showed only kappa FLC, 10 only lambda FLC, while 15 had both kappa and lambda FLC. The CSF of 4 MS patients was FLC negative. In both cases of neurosyphilis FLC bands were observed. FLC were never found in normal CSF. Among the indexes of intrathecal immunological activity (IgG oligoclonal bands, FLC, IgG index, intra-blood-brain barrier IgG synthesis rate, pleocytosis) the FLC proved to be the second most frequent abnormality in MS CSF, the presence of IgG oligoclonal bands being the first. In one MS case an FLC band was found, while all the other indexes of intrathecal IgG production were negative. A high correlation was found between an elevated number of FLC and pleocytosis. The presence of FLC in MS CSF seems to indicate a recent immunological stimulation leading to increased synthesis of FLC within the CNS.     

Oligoclonal immunoglobulin bands in cerebrospinal fluid of patients with Alzheimer''s disease and vascular dementia

We examined serum and cerebrospinal fluid (CSF) of 16 patients with Alzheimer's disease (AD), 28 patients with vascular dementia (VD), their age-matched controls and multiple sclerosis (MS) patients in order to evaluate the humoral immune response within the central nervous system both quantitatively and qualitatively. Intra-blood-brain barrier (BBB) protein synthesis was calculated by CSF IgG index. The presence of oligoclonal banding (OCB) was investigated with agarose isoelectric focusing (IEF) followed by immunoblotting with antihuman IgG. No patient with AD and only 4 patients with VD had slightly elevated IgG indexes, and no statistically significant differences in the indexes were found between the two groups. No bands were found in the CSF of AD patients but 3 VD patients had OCB in both serum and CSF. One VD patient had bands in serum but no bands in CSF. No kappa or lambda free light chains were found in those demented patients with demonstrable bands in the CSF and serum. No OCB were found in control sera and CSF. For comparison, the majority of patients with MS had OCB in CSF. Thus, no consistent increase of intrathecal protein synthesis was found in patients with AD and VD. Methodological differences explain at least part of the conflicting results published earlier.     

Identification of light chain type bands in CSF and serum oligoclonal IgG from patients with multiple sclerosis

The light (L) chain types (kappa and lambda) of oligoclonal IgG bands of matching CSF and serum from 10 MS patients were identified in immunofixation after isoelectric focusing in polyacrylamide gel. Each specimen showed 10-15 oligoclonal bands in pH region of 7.5-9.3. In 7 MS CSF and 5 sera a greater number of oligoclonal IgG bands were of kappa (kappa)-type whereas in 3 CSF and 2 sera the majority was of lambda (lambda)-type. In 3 sera a clearcut correlation of bands with either type of L chain was not observed due to diffuse staining background. Only a small number of oligoclonal IgG bands in 7 of 10 CSF and serum pairs had identical isoelectric points and the same type of L chain. The results show that the individual MS patient had oligoclonal IgG bands in serum, differ with respect to number, isoelectric point and L chain type from the oligoclonal IgG profile seen in the patient's CSF.     

Increased free light chains in the urine from patients with multiple sclerosis

We quantitated free kappa (kappa) and lambda light (L) chains in coded urine specimens from subjects with clinically definite multiple sclerosis (MS) (N = 56), other neurologic diseases (OND) (N = 30), and age-matched normal controls (N = 28). Urine from MS patients showed statistically significant increases in free L chains compared with the other groups, although there was overlap between MS patients and OND patients. The ratio of kappa/creatinine was significantly greater in the relapsing-remitting MS group than in patients with clinically stable MS, OND, and normal controls. Elevated free L chains were usually independent of urinary albumin and beta 2-microglobulin levels. Serial studies showed that urinary free kappa/creatinine ratios were elevated during periods of clinical worsening in seven of eight MS patients and subsequently decreased during clinical recovery. The measurement of free L chains in urine obtained at intervals from MS patients may be useful as a marker to monitor disease activity.     

Immunoglobulin light chain patterns in the cerebrospinal fluid. A study with special reference to the occurrence of free light chains in cerebrospinal fluid with and without oligoclonal immunoglobulin G

The immunoglobulin light chain patterns were studied in paired cerebrospinal fluid (CSF) and serum samples from 30 controls, 70 multiple sclerosis (MS) patients, 18 subjects with other inflammatory neurological diseases and 17 patients with other non-inflammatory neurological disorders. In MS, all CSF samples examined by two-dimensional gel electrophoresis exhibited clonally restricted light chain components. Isoelectric focusing and immunoblotting detected free light chains in around 90% of CSF samples from patients with MS or other inflammatory diseases. These components were clonally restricted, appeared in both mono- and dimeric forms and occurred in CSF samples with as well as without oligoclonal immunoglobulin G bands. Generally, the positive CSF samples contained kappa as well as lambda free lights chains. Such components were not detected in the sera, nor in the CSF samples from controls or patients with non-inflammatory diseases.     

High sensitivity of free lambda and free kappa light chains for detection of intrathecal immunoglobulin synthesis in cerebrospinal fluid

Background – So far, an inflammation of the central nervous system (CNS) is diagnosed by immunoglobulin measurement in cerebrospinal fluid (CSF) and serum as well as by determination of the oligoclonal bands. With the free kappa and lambda light chains, new markers to diagnose intrathecal synthesis are available. Methods – In addition to routine diagnostic tests and the assessment of standard parameters, free immunoglobulin light chains were measured in the CSF of patients with neurological disorders. Results – A significant agreement was found between an increase in free kappa light chain CSF serum quotients and results of the currently widely applied method of oligoclonal band measurement for the detection of intrathecal immunoglobulin synthesis. A sensitivity of 95% and 100% specificity for free kappa light chain concentrations at a cut‐off of 0.41 mg/l was determined for free kappa light chains compared with oligoclonal bands. However, the free lambda light chains in 20 out of the 110 investigated samples were characterized by inconsistent behaviour. These otherwise unremarkable samples yielded increased CSF quotients, leading to the assumption that free lambda light chains represent a highly sensitive measure of intrathecal immunologlobulin synthesis. Thirteen of the 20 samples described above were obtained from patients with cerebral infarction, 4 samples derived from patients with cerebral paresis (primarily facial paresis), one sample was from a patient with multisystem atrophy and two were obtained from patients with migraine and neuralgia. Conclusion – These findings suggest that the high sensitivity of lambda light chains for the detection intrathecal immunoglobulin synthesis may be of benefit in establishing clinical diagnoses.     

Cerebrospinal fluid free kappa light chains versus IgG findings in neurological disorders: qualitative and quantitative measurements

In this study free kappa light chains in cerebrospinal fluid (CSF) were determined both by an affinity mediated capillary blotting technique after isoelectric focusing (IEF) in agarose gel and by a quantitative enzyme linked immunosorbent assay (ELISA). The free kappa results were compared with the IgG findings in 4 neurological patient groups with a distinct CSF IgG pattern: (1) CSF without oligoclonal IgG bands, (2) CSF with serum derived IgG bands, (3) CSF restricted IgG bands and (4) CSF restricted and serum derived IgG bands. Oligoclonal free kappa bands are nearly absent in CSF of groups 1 + 2, and present in 88% of group 3 and 84% of group 4 patients. We could also establish free kappa indices from specimens in the 4 groups in analogy to IgG indices. Group 1 had a median free kappa index of 1.1, group 2: 1.0 and groups 3 + 4: 10.0. The correspondence between immunoblot and index findings for free kappa is better than for IgG. Free kappa index is more sensitive but somewhat less specific than IgG index for establishing intrathecal immune production.     

Light chain composition of CSF oligoclonal IgG bands in multiple sclerosis and subacute sclerosing penecephalitis

The light chain composition of MS and SSPE CSF oligoclonal IgG bands was examined using isoelectric focusing and sensitive peroxidase-anteperoxidase (PAP) staining technique specific for gamma heavy chains (γ), kappa light chains (κ), or lambda light chains (λ) and a radioimmunoassay (RIA) for γ, κ, or λ. Many bands in the 7 MS and 4 SSPE CSF examined were monoclonal, staining for either IgG-κ or IgG-λ. By staining, all MS CSF were κ predominant; SSPE CSF were variously κ orλ predominant. RIA confirmed the κ predominance of MS CSF. Three MS and 2 SSPE CSF contained bands staining for λ alone, i.e. free light chains. Analysis of RIA data confirmed these findings in 2 MS cases. The difference in light chain predominance of MS and SSPE CSF may reflect differences in the antigenic target, or the age of patient at the time when band-synthesizing clones are triggered. Six of 7 MS and all 4 SSPE CSF contained oligoclonal bands staining for γ and for both κ and λ, probably representing artifacts of IEF. No predominant immunochemical differences between bands in MS and SSPE were detected.     

Distinct heterogeneity of IgG immune response in cerebrospinal fluid (CSF) detected by isoelectric focusing (IEF) with extended immunofixation

An optimized automated IEF procedure in polyacrylamide micro gels and immunofixation with 10 monospecific antibodies against some fragments of the IgG molecule and against the whole IgG isotypes IgG(1), IgG(2), IgG(3), IgG(4), respectively, detected oligoclonal bands (OBs) within acid, neutral, and alkaline ranges of the gels. Accuracy and reliability of the OB assay for detection of an intrathecal IgG synthesis proved to be higher with immunofixation than with silver staining of bands precipitated by trichloroacetic acid. CSF OBs were specified as lambda or kappa IgG subfractions, respectively, duplex IgGs precipitated with anti-lambda, anti-kappa, and anti-Fc antibodies at the same pI. Most of OBs were classified as belonging to either IgG(1), IgG(2), IgG(3), or IgG(4) isotypes in CSF. The IEF procedure additionally allowed the discrimination of both free light chains and possible "free" heavy gamma chain fragments in CSF, when immunofixation was done with monospecific antibodies against both light chains and gamma chain fragments (e.g. anti-F(ab')(2), anti-Fd, anti-Fc, anti-C(H)2). The results pointed out a distinct heterogeneity of the IgG immune response in human CSF. The IEF procedure with extended immunofixation is recommended for completion of the basic laboratory procedures used in neuroimmunology in order to discriminate inflammatory processes in human CNS.