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

The Diagnostic Utility of Oligoclonal Bands in Multiple Sclerosis: A Time-Course Analysis

Background: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) are a hallmark of MS and reflect intrathecal IgG synthesis and inflammation. This study aims to analyze the temporal distribution of IgG OCBs in the CSF of patients with a definitive diagnosis of MS. Methods: This retrospective study included 500 patients with diagnosed MS. Patients were divided into four groups according to diagnostic epochs: Group 1 (Pre-2001 or Pre-McDonald), Group 2 (2001-2010 or McDonald 2001-Polman 2010), Group 3 (2010-2018 or Polman 2010), and Group 4 (Post-2018 or Thompson 2017). Statistical analyses examined temporal and sex differences in OCB positivity rates. Results: OCB positivity was lower in Group 4 (69.2%) compared to Group 1 (85.4%) in the overall population (p = 0.0022). A decrease in OCB positivity was observed in Groups 3 (62.5%) and 4 (71.8%) compared to Group 1 (92.5%) among males (p = 0.0117 and p = 0.0198, respectively) and in Group 4 (68.1%) compared to Group 1 (82.5%) among females (p = 0.0274). Conclusions: The present study provides valuable insights into temporal trends in CSF positivity among patients diagnosed with MS. There was an overall decrease in OCB positivity rates over the years, particularly in the post-2018 period.

Kappa Free Light Chains in Multiple Sclerosis as a Marker of Intrathecal Humoral Response: A Sex-Disaggregated Study

BACKGROUND

Kappa free light chains (KFLCs) are emerging as promising biomarkers for intrathecal B cell activity for diagnosing multiple sclerosis (MS) through cerebrospinal fluid (CSF) analysis. In this study, we evaluated the ability of KFLC formulas to identify the presence of MS and their agreement with the 'gold standard' of CSF IgG oligoclonal bands (OCBs).

METHODS

A total of 233 patients were included in this study: 149, comprising 43 males and 106 females, had MS, and the remainder, 40 males and 44 females, had other neurological diseases (ONDs). We evaluated the potential of KFLCs in terms of sensitivity, specificity, and accordance. All analyses were conducted using a sex-disaggregated approach.

RESULTS

KFLCs showed a high sensitivity for both sexes with respect to the diagnosis of MS, with values between 74.42% and 93.03%. The specificity of the various formulas was much lower for females when compared to males, with values between 45.45% and 59.09%, with a significant difference between the two sexes for the K Index > 5.9 (p = 0.0451). Cohen's kappa showed substantial agreement for men and moderate agreement for women between the KFLC indices and OCB.

CONCLUSIONS

This study highlights the potential of KFLCs as a biomarker for MS but emphasises the need for sex-specific thresholds to improve diagnostic accuracy.

CSF Free Light Chains as a Marker of Intrathecal Immunoglobulin Synthesis in Multiple Sclerosis: A Blood-CSF Barrier Related Evaluation in a Large Cohort

Objectives: The importance of immunoglobulin G (IgG) oligoclonal bands (OCB) in the diagnosis of multiple sclerosis (MS) was reaffirmed again in the recently revised MS diagnostic criteria. Since OCB testing is based on non-quantitative techniques and demands considerable methodological experience, measurement of CSF immunoglobulin free light chains (FLC) has been suggested as quantitative alternative to OCB. We aimed to establish reference values for FLC measures and evaluate their diagnostic accuracy with regard to the diagnosis of MS.

Methods: Immunoglobulin kappa (KFLC) and lambda (LFLC) free light chains were prospectively measured by nephelometry in CSF and serum sample pairs in 1,224 patients. The analyzed cohort included patients with MS, other autoimmune or infectious inflammatory diseases of the nervous system as well as 989 patients without signs for nervous system inflammation.

Results: Regarding diagnosis of MS, the diagnostic sensitivity and specificity of intrathecal KFLC ratio were 93.3 and 93.7% using the CSF-serum albumin ratio-dependent reference values, 92.0 and 95.9% for intrathecal KFLC ratio applying the ROC-curve determined cut-off levels, 62.7 and 98.3% for IgG index, 64.0 and 98.8% for intrathecal IgG synthesis according to Reiber diagrams, and 94.7 and 93.3% for OCB. Diagnostic sensitivity and specificity of intrathecal LFLC were clearly lower than KFLC.

Conclusions: Intrathecal KFLC and OCB showed the highest diagnostic sensitivities for MS. However, specificity was slightly lower compared to other quantitative IgG parameters. Consequently, CSF FLC may not replace OCB, but it may support diagnosis in MS as a quantitative parameter.

Free light chains: Eclectic multipurpose biomarker

The production of antibodies is accompanied by a slight excess of synthesis of κ and λ immunoglobulin light chains; small amounts of them are released in the peripheral blood and can also be found in various body fluids, such as synovial fluid, cerebrospinal fluid, urine and saliva. They are rapidly filtered by the glomerulus and >99% are reabsorbed from the cells of the proximal convoluted tubule, making them present in the urine in only trace amounts. The production of an excess of protein without a reason or a specific function in a biological system is rare. Free light chains, considered for years a waste product of Ig synthesis, are currently known to be very active molecules, able to bind antigens as well as whole immunoglobulin and helping to develop specific antibody affinity. The ability of free light chains to activate mast cells and then become an active part of the pathogenic mechanisms of chronic inflammatory diseases has increased interest in their clinical use, both as an attractive therapeutic target or as a biochemical marker of disease evolution or remission. This is an overview of relevant scientific interest that immunoglobulin light chains κ and λ have attracted over the years, a report on the progress in knowledge about their structure and function, with a special focus on their biological meaning and potential clinical utility in different diseases.

Assessment of Intrathecal Free Light Chain Synthesis: Comparison of Different Quantitative Methods with the Detection of Oligoclonal Free Light Chains by Isoelectric Focusing and Affinity-Mediated Immunoblotting

Objectives

We aimed to compare various methods for free light chain (fLC) quantitation in cerebrospinal fluid (CSF) and serum and to determine whether quantitative CSF measurements could reliably predict intrathecal fLC synthesis. In addition, we wished to determine the relationship between free kappa and free lambda light chain concentrations in CSF and serum in various disease groups.

Methods

We analysed 166 paired CSF and serum samples by at least one of the following methods: turbidimetry (Freelite™, SPA_PLUS), nephelometry (N Latex FLC™, BN ProSpec), and two different (commercially available and in-house developed) sandwich ELISAs. The results were compared with oligoclonal fLC detected by affinity-mediated immunoblotting after isoelectric focusing.

Results

Although the correlations between quantitative methods were good, both proportional and systematic differences were discerned. However, no major differences were observed in the prediction of positive oligoclonal fLC test. Surprisingly, CSF free kappa/free lambda light chain ratios were lower than those in serum in about 75% of samples with negative oligoclonal fLC test. In about a half of patients with multiple sclerosis and clinically isolated syndrome, profoundly increased free kappa/free lambda light chain ratios were found in the CSF.

Conclusions

Our results show that using appropriate method-specific cut-offs, different methods of CSF fLC quantitation can be used for the prediction of intrathecal fLC synthesis. The reason for unexpectedly low free kappa/free lambda light chain ratios in normal CSFs remains to be elucidated. Whereas CSF free kappa light chain concentration is increased in most patients with multiple sclerosis and clinically isolated syndrome, CSF free lambda light chain values show large interindividual variability in these patients and should be investigated further for possible immunopathological and prognostic significance.

Oligoclonal free light chains in cerebrospinal fluid as markers of intrathecal inflammation. Comparison with oligoclonal IgG

AIMS

To compare the sensitivity and specificity of CSF-restricted oligoclonal IgG and free light chains as markers of multiple sclerosis and other inflammatory neurological diseases.

METHODS

196 paired CSF and serum samples were examined for oligoclonal IgG and oligoclonal free light chains. The sensitivity and specificity of the tests were calculated and optimal cut-offs for the number of CSF-restricted oligoclonal bands were then determined by analysis of receiver operating characteristic curves.

RESULTS

Optimal cut-off values were ≥5 IgG bands for multiple sclerosis, ≥4 IgG bands for inflammatory neurological disease, ≥6 free κ, and ≥2 free λ bands for both purposes. Using these cut-off values, sensitivities and specificities for multiple sclerosis were 83.8% and 91.3% for IgG, 83.8% and 81.0% for free κ, and 67.6% and 75.4% for free λ. For inflammatory neurological disease, sensitivities and specificities were 60.8% and 95.7% for IgG, 69.6% and 92.6% for free κ, and 64.8% and 86.2% for free λ.

CONCLUSIONS

Although exact cut-off values may vary according to method, reporting borderline results as positive, may compromise the specificity of the test and should be avoided.. The detection of intrathecal free light chain synthesis may be of value especially when the oligoclonal IgG test is negative or borderline, even though its specificity is slightly lower.

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.

Partial T cell-depleted allogeneic stem cell transplantation following reduced-intensity conditioning creates a platform for immunotherapy with donor lymphocyte infusion and recipient dendritic cell vaccination in multiple myeloma

Allogeneic stem cell transplantation (SCT) in multiple myeloma (MM) may induce a curative graft-versus-myeloma (GVM) effect. Major drawback in unmanipulated reduced-intensity conditioning (RIC) SCT is the risk of severe and longstanding graft-versus-host-disease (GVHD). This study demonstrates that transplantation with a partial T cell-depleted graft creates a platform for boosting GVM immunity by preemptive donor lymphocyte infusion (DLI) and recipient dendritic cell (DC) vaccination, with limited GVHD. All 20MM patients engrafted successfully. Chimerism analysis in 19 patients evaluable at 3 months revealed that 7 patients were complete donor, whereas 12 patients were mixed chimeric. Grade II acute GVHD (aGVHD) occurred in 7 patients (35%) and only 4 patients (21%) developed chronic GVHD (cGVHD). Fourteen patients received posttransplantation immunotherapy, 8 preemptive DLI, 5 patients both DLI and DC vaccination, and 1 patient DC vaccination only. DC vaccination was associated with limited toxicity, and none of these patients developed GVHD. Importantly, overall treatment-related mortality (TRM) at 1 year was low (10%). Moreover, the overall survival (OS) is 84% with median follow-up of 27 months, and none of the patients died from progressive disease. These findings illustrate that this novel approach is associated with limited GVHD and mortality, thus creating an ideal platform for adjuvant immunotherapy.

Mast cells and nerves tickle in the tummy: implications for inflammatory bowel disease and irritable bowel syndrome

Mast cells are well known as versatile cells capable of releasing and producing a variety of inflammatory mediators upon activation and are often found in close proximity of neurons. In addition, inflammation leads to local activation of neurons resulting in the release neuropeptides, which also play an important immune modulatory role by stimulation of immune cells. In intestinal disorders like inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), the number of mast cells is known to be much higher than in the normal intestine. Moreover, both these disorders are also reported to be associated with alterations in neuropeptide content and in neural innervation. Mutual association between mast cells and enteric nerves has been demonstrated to be increased in pathophysiological conditions and contribute to spreading and amplification of the response in IBD and IBS. In this review the focus lies on studies appointed to the direct interaction between mast cells and nerves in IBD, IBS, and animal models for these disorders so far.

Free immunoglobulin light chains as target in the treatment of chronic inflammatory diseases

Immunoglobulin free light chains were long considered irrelevant bystander products of immunoglobulin synthesis by B lymphocytes. To date, different studies suggest that free light chains may have important functional activities. For instance, it has been shown that immunoglobulin free light chains can elicit mast cell-driven hypersensitivity responses leading to asthma and contact sensitivity. Free light chains also show other biologic actions such as anti-angiogenic and proteolytic activities or can be used as specific targeting vehicles. Levels of free light chain levels in body fluids increase markedly in diseases such as multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. In this review, we will focus on the unexpected biological activities of immunoglobulin free light chains with special attention to its possible role in the induction of chronic inflammatory diseases.

Quantification of Immunoglobulin Free Light Chains in CerebroSpinal Fluid by Nephelometry

Oligoclonal free light chains (FLC) banding has been described in multiple sclerosis (MS) and should be correlated with disease activity. However, discrepancies between studies have been reported because of differences in methods. A new quantitative, rapid, and automated method using nephelometry is now available. Our objective was to investigate the interest of this method for the diagnosis and prognosis of MS. For this purpose, FLC index was determined in paired samples of CSF and serum from consecutive and unselected patients from the same department of neurology. We enrolled 89 patients (33 MS, 15 "possible MS", and 41 controls) and correlated with IgG index, IgG oligoclonal banding, and clinical MS progression criteria. The main results were (1) FLC kappa index was more sensitive but less specific than IgG index for the diagnosis of MS, (2) two MS patients were negative for oligoclonal banding but exhibited a positive kappa index, (3) no relation between FLC kappa indices, MS clinical criteria, and disease progression was found. In conclusion, FLC kappa index should be considered as a useful complementary test for MS diagnosis. Its pronostic interest remains to be determined on a larger cohort of possible MS patients.

Kappa Free Light Chains in Cerebrospinal Fluid as Markers of Intrathecal Immunoglobulin Synthesis

Background: Intrathecal immunoglobulin synthesis is observed in several inflammatory disorders of the central nervous system, but its detection by current laboratory tests is either tedious or relatively insensitive. We assessed the diagnostic accuracy of an assay for κ free light chains (κFLC) in cerebrospinal fluid (CSF) and serum, and compared it with traditional tests for intrathecal immunoglobulin synthesis.

Methods: κFLCs were measured by nephelometry in CSF/serum pairs from 112 patients. Samples were excluded if blood contamination of CSF as a result of traumatic lumbar puncture (n = 12) or monoclonal bands in both CSF and serum (n = 5) were present. The remaining sample pairs were grouped according to the presence (n = 71) or absence (n = 24) of oligoclonal bands. Data were analyzed as κFLC concentrations in CSF, as κFLC CSF/serum ratios, and by use of the quotient diagram described previously for immunoglobulins.

Results: Both κFLC concentrations in CSF and the κFLC CSF/serum ratio identified patients with oligoclonal bands with high specificity and sensitivity. The areas under the ROC curves were 0.991 (95% confidence interval, 0.944–0.998) and 0.978 (0.924–0.996), respectively. Exclusion of patients with impaired blood–CSF barrier function further improved diagnostic accuracy. To account for patients with impaired blood–CSF barrier function, data were also analyzed in a quotient diagram. Only two patients without detectable oligoclonal bands would have been misclassified by this approach.

Conclusions: Our data indicate that the nephelometric assay for κFLCs in CSF reliably detects intrathecal immunoglobulin synthesis. This automated and quantitative method could simplify the diagnostic procedure for CSF analysis in the routine laboratory.

Binding of Free Immunoglobulin Light Chains to VpreB3 Inhibits Their Maturation and Secretion in Chicken B Cells

The VpreB3 gene product was first characterized as an immunoglobulin (Ig) mu heavy chain-binding protein in mouse precursor B (pre-B) cells. Although its function is unknown, it has been proposed to participate in the assembly and transport of the pre-B cell receptor. We have identified a VpreB3 orthologous gene in chicken that is located close to the immunoglobulin light chain (LC) gene cluster and specifically expressed in the bursa of Fabricius. By overexpressing VpreB3 in the DT40 IgM(+) immature chicken B cell line, we have characterized VpreB3 as an endoplasmic reticulum-resident glycoprotein that binds preferentially to free IgLC. However, binding to IgHC is observed in IgLC-deficient DT40 cells. Interaction of VpreB3 with free IgLC is partly covalent and induces retention of free IgLC in the endoplasmic reticulum, preventing their secretion without affecting IgM surface expression. Our results demonstrate that this evolutionarily conserved molecule may play a role in the regulation of the maturation and secretion of free IgLC in B cells. We discuss possible implications in the regulation of the immune response.

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.

Molecular heterogeneity, detected by two electrophoretic micro procedures, of IgG in human cerebrospinal fluid (CSF)

Semi-automated electrophoretic procedures in the PhastSystem (Amersham Pharmacia Biotech) with micro polyacrylamide gels (PAGs) and SDS-PAG gradients were modified to analyze IgG in human cerebrospinal fluid (CSF) and matched serum samples with respect to the molecular IgG structure L-H-H-L. Isoelectric focusing (IEF) with specific immunofixation detected discrete IgG bands in CSF standing out against a polyclonal and monoclonal background pattern in CSF and serum; they were denoted oligoclonal bands (IgG OBs) (OB assay positive) indicating IgG synthesis in the central nervous system (CNS) of patients with subacute and chronic processes of inflammatory CNS disorders; assay was negative with identical (mirror) bands in CSF and serum for other CNS processes. IgG OBs were specified as lambda (kappa) IgG subfractions, precipitated with the anti-light (L) chains lambda (kappa) and anti-heavy (H) chain fragments (Fd, Fc, C(H)2) as well as with anti-F(ab')(2), and as duplex IgGs with kappa and lambda OBs at the same pI. With SDS-PAG gradient electrophoresis and specific immunofixation more than six IgG fractions were detected and classed according to apparent molecular weights of a S-sulfonated human IgG standard; they were characterized with the monospecific antibodies against the L and H chain fragments as 25, 50, 75, 100, 125 and 150 kD fractions containing combinations of L and H chains as well as mixtures of both L and H chain fragments of varying dimensions. Generally, this molecular IgG heterogeneity could not be connected with the IgG OB heterogeneity revealed by IEF; but single OBs in the strongly alkaline pH region of PAG may correspond to H fragments with basic pI. Nevertheless, evidence for the existence of both free L chains and the free H chain were revealed as specific OBs with IEF and with the anti-L and anti-H antibodies in the 25 kD and 50 kD fractions, respectively, of CSF samples of six patients with diverse CNS diseases. Further experiments are needed to elicit the origin of the molecular IgG heterogeneity during the immune response of subacute and chronic inflammatory processes in human CNS.

Immunoglobulin free light chains and mast cells: pivotal role in T-cell-mediated immune reactions?

Immunoglobulin (Ig) free light (L)-chains have long been considered as the meaningless remnants of a spillover in the regular Ig production by B cells. The recently discovered role for Ig free L-chains in mediating hypersensitivity-like responses sheds new light on their potential role in immune responses. Ig free L-chains can sensitize mast cells, such that a second encounter with the appropriate antigen results in mast-cell activation. The possible importance of this reaction for the induction of T-cell-mediated immune reactions, leading to contact sensitivity, multiple sclerosis and rheumatoid arthritis is discussed.

Evidence of cerebrospinal fluid free kappa light chains in AIDS patients with Toxoplasma gondii encephalitis

Cerebrospinal fluid (CSF) free light chains of kappa or lambda (FLC kappa/lambda) type were investigated by affinity mediated blotting technique (AMI) and ELISA in 28 patients of which nine with AIDS and Toxoplasma gondii encephalitis (AIDS, TE), 11 with AIDS with or without other CNS AIDS-related opportunistic infections (non-TE AIDS) and eight control patients with or without inflammatory neurological disorders (control group). CSF restricted oligoclonal FLC bands either of k or lambda isotype or both were found by AMI in 18 (90%) out of 20 AIDS patients, while a CSF pattern predominantly characterized by FkappaLC rather than FlambdaLC was observed in eight (88.8%) out of nine TE patients. No FLC components were detected in the matched sera of TE or non-TE AIDS patients or in the CSF and sera from control group. The anti-parasite-specific FkappaLC CSF/serum mean levels and the T. gondii-specific FkappaLC index values were found by ELISA to be significantly more elevated in TE patients when compared to non-TE AIDS or control group. These findings suggest that the increased production of T. gondii-specific FkappaLC could provide insights into pathogenesis of reactivated TE in immunocompromised patients and may have important diagnostic usefulness.

Atrial natriuretic peptide increases albuminuria in type I diabetic patients: evidence for blockade of tubular protein reabsorption

BACKGROUND

It has been suggested that atrial natriuretic peptide (ANP) contributes to the glomerular hyperfiltration of diabetes mellitus. Infusion of ANP increases the urinary excretion of albumin in patients with type I diabetes mellitus (IDDM). Although the increased albuminuria is attributed to a rise in glomerular pressure, alterations in tubular protein handling might be involved.

PATIENTS AND METHODS

We have studied the effects of ANP in nine microalbuminuric IDDM patients. After obtaining baseline parameters, ANP was infused over a 1-h period (bolus 0.05 microgram kg-1, infusion rate 0.01 microgram kg-1 min-1). Renal haemodynamics, sodium and water clearance and tubular protein handling were studied.

RESULTS

The glomerular filtration rate (GFR) increased from 116.4 +/- 8.9 to 128.3 +/- 8.8 mL min-1 1.73 m-2, whereas the effective renal plasma flow (ERPF) decreased from 534.3 +/- 44.3 to 484.9 +/- 33.3 mL min-1 1.73 m-2 (P < 0.05). As a result, the filtration fraction was significantly higher during infusion of ANP. ANP attenuated proximal tubular sodium reabsorption. Urinary albumin excretion rose from 87.57 +/- 21.03 to 291.40 +/- 67.86 micrograms min-1 (P < 0.01). Changes in the urinary excretion of beta 2-microglobulin and free kappa light chains were more marked, the excretion of beta 2-microglobulin increasing from 0.28 +/- 0.21 to 51.87 +/- 10.51 micrograms min-1 (P < 0.01), and of free kappa-light chains from 4.73 +/- 1.74 to 46.14 +/- 6.19 micrograms min-1 (P < 0.01).

CONCLUSIONS

The observed rise in albuminuria during infusion of ANP does not simply reflect a change in glomerular pressure, but might at least partly result from an attenuation of tubular protein reabsorption.

Intrathecal synthesis of free immunoglobulin light chains in multiple sclerosis

OBJECTIVE

The detection of oligoclonal immunoglobulin free light chains (FLC) in the diagnosis of multiple sclerosis (MS) was compared to IgG isoelectric focusing.

MATERIAL AND METHODS

Cerebrospinal fluid and serum samples from 69 patients with possible first attacks of MS, 50 patients with clinically definite MS (CDMS), and 118 patients with other neurological diseases (OND) were analyzed. IgG and FLC oligoclonal bands were detected by isoelectric focusing and immunoperoxidase staining.

RESULTS

Intrathecal synthesis of IgG, kappa FLC, and lambda FLC oligoclonal bands, respectively, was seen in 92%, 92%, and 86% of MS patients; in 61%, 62%, and 64% of patients with possible first attacks of MS; and in 3%, 3%, and 8% of the patients with OND. In control patients without IgG synthesis intrathecal lambda FLC synthesis was more common than kappa FLC synthesis (P=0.03).

CONCLUSION

Kappa FLC detection proved as useful as IgG analysis for the laboratory diagnosis of MS whereas the presence of intrathecal lambda FLC synthesis was less specific.

Body fluid markers to monitor multiple sclerosis: the assays and the challenges

The need for reliable markers of disease activity in multiple sclerosis (MS) to better guide basic research, diagnosis, treatment, and monitoring of therapy is well-recognized. A recent European Charcot Foundation Symposium (Body fluid markers for course and activity of disease in multiple sclerosis (Madrid, Spain, October 2-4, 1997) organized by the European Charcot Foundation and the Fundación Española de Esclerosis Múltiple (the Spanish Multiple Sclerosis Foundation) brought together experts in the field to review the state of the art for the technology measuring markers in body fluids. An array of different approaches was presented to measure a wide diversity of classic and novel marker molecules, including cytokines, adhesion molecules, myelin compounds, and free antibody light chains, in either blood, urine, or cerebrospinal fluid. Here, recent progress in these approaches is assessed in the context of distinct pathophysiological stages of the disease, the requirements which such molecules and assays should ideally meet, and the practical and conceptual challenges which they face. Recommendations for further improvements are described.