The clinical significance of single or double bands in cerebrospinal fluid isoelectric focusing. A retrospective study and systematic review

Abnormal Cerebrospinal Fluid Cytology in Functional Movement Disorders

OBJECTIVE

The role of inflammation and neuroimmune mechanisms, which have been documented in various neuropsychiatric disorders including the seizure subtype of functional neurological disorder, remains unclear in functional movement disorders (FMD). To explore these mechanisms, we analyzed selected inflammatory markers in cerebrospinal fluid (CSF) in patients with FMD.

METHODS

We compared CSF markers in 26 patients with clinically established FMD (20 females; mean [SD] age = 43.3 [10.9], disease duration = 3.9 [3], range = 0.1-11 years; mean follow-up after lumbar puncture = 4.3 [2] years, range = 0.5-7 years) and 26 sex- and age-matched clinical controls with noninflammatory nonneurodegenerative neurological disorders, mostly sleep disorders.

RESULTS

Sixty-five percent of FMD patients versus 15% of controls showed cytological abnormalities (i.e., increased white blood cells [WBC] count, signs of WBC activation, or both; odds ratio [OR] = 9.85, 95% confidence interval = 2.37-52.00, p < .01, corrected), with a significantly higher frequency of an isolated lymphocytic activation, 35% versus 0% (OR = ∞, 95% confidence interval = 2.53-∞, p < .05, corrected). There were no differences in CSF protein and albumin levels, quotient albumin, IgG index, and oligoclonal bands. CSF abnormalities were not associated with more severe motor symptoms or a higher frequency of depression in FMD.

CONCLUSIONS

Our results suggest a possible involvement of immune mechanisms in the pathophysiology of (at least a subtype of) FMD that deserves further investigation.

Oligoclonal bands

Oligoclonal bands (OCBs) represent the presence of intrathecal immunoglobulin G (IgG) as detected by isoelectric focusing and immunofixation. Cerebrospinal fluid (CSF) analysed alongside a paired serum sample gives five different immunofixation patterns. These are: type 1-the normal physiological state with no intrathecal IgG synthesis; type 2-evidence for intrathecal IgG synthesis, with CSF-restricted OCBs; type 3-evidence for intrathecal IgG synthesis, with CSF-restricted OCBs, but with additional, identical bands in the CSF and serum; type 4-absence of intrathecal IgG synthesis, but with identical OCBs in CSF and serum; and type 5-absence of intrathecal IgG synthesis, with a monoclonal band in CSF and serum. Analysis of these patterns can help to diagnose a range of neurological conditions, including multiple sclerosis. However, it is important to interpret OCB results alongside other CSF tests and their clinical context.

Multiple Sclerosis: From the Application of Oligoclonal Bands to Novel Potential Biomarkers

Multiple sclerosis is a chronic immune-mediated disorder of the central nervous system with a high heterogeneity among patients. In the clinical setting, one of the main challenges is a proper and early diagnosis for the prediction of disease activity. Current diagnosis is based on the integration of clinical, imaging, and laboratory results, with the latter based on the presence of intrathecal IgG oligoclonal bands in the cerebrospinal fluid whose detection via isoelectric focusing followed by immunoblotting represents the gold standard. Intrathecal synthesis can also be evidenced by the measurement of kappa free light chains in the cerebrospinal fluid, which has reached similar diagnostic accuracy compared to that of oligoclonal bands in the identification of patients with multiple sclerosis; moreover, recent studies have also highlighted its value for early disease activity prediction. This strategy has significant advantages as compared to using oligoclonal band detection, even though some issues remain open. Here, we discuss the current methods applied for cerebrospinal fluid analysis to achieve the most accurate diagnosis and for follow-up and prognosis evaluation. In addition, we describe new promising biomarkers, currently under investigation, that could contribute both to a better diagnosis of multiple sclerosis and to its monitoring of the therapeutic treatment response.

A dynamic interpretation of κFLC index for the diagnosis of multiple sclerosis: a change of perspective

BACKGROUND

Previous studies attempted to define the best threshold for κ free light chains (κFLC) index, confirming higher sensitivity (Se) but less specificity (Sp) compared with IgG oligoclonal bands (OCB) for the diagnosis of MS.

OBJECTIVE

To evaluate the diagnostic accuracy of different κFLC index intervals in a miscellaneous cohort of neurological patients, proposing a procedural flowchart for MS diagnosis.

METHODS

We analyzed data from 607 patients diagnosed with MS (179), CIS (116), other inflammatory (94) or non-inflammatory neurological diseases (218). Measures of diagnostic accuracy were reported for different potential thresholds of κFLC index, and for IgG OCB and IgG index. Binary logistic regression was to used to calculate the odds of being diagnosed with MS based on each increase of κFLC index.

RESULTS

CSF IgG OCB showed 72.2% Se (CI 95% 68.4-75.7) and 95.2% Sp (CI 95% 93.1-96.7) in discriminating between MS/CIS and controls, with an AUC of 0.84 (CI 95% 0.80-0.87). The highest diagnostic accuracy was reported for κFLC index cut-off of 5.0 (Se = 85.4%, Sp = 90.4%, AUC = 0.88), while a threshold of 11.0 exhibited higher Sp (95.5%, 95% CI 93.1-97.1) than IgG OCB. AUCs for all thresholds between 4.25 and 6.6 were not significantly different from each other, but were significantly higher than the AUC of IgG OCB (p < 0.05). The odds of being diagnosed with MS/CIS increased by 17.1% for each unit increase of κFLC index (OR = 1.17; 95% CI 1.12-1.23; p < 0.001).

CONCLUSION

κFLC index performed better than CSF IgG OCB in supporting the diagnosis of MS/CIS, with the advantage of being a cost-effective and quantitative analysis.

Do we still need OCBs in MS diagnosis and how many?

BACKGROUND

CSF-specific oligoclonal bands (CSF-OCBs) can be used for dissemination in time (DIT) in the 2017 multiple sclerosis (MS) diagnostic criteria. A cut-off of ≥2 CSF-OCBs was recommended but studies have suggested ≥3 CSF-OCBs may be superior.

OBJECTIVES

To assess utility of ≥2 and ≥3 CSF-OCBs as a cut-off for MS diagnosis.

METHODS

Paired serum and CSF-OCBs sent to the Walton Centre, UK between July 2018 and June 2020 were included. CSF-OCBs were assessed using isoelectric focussing and reviewed by two blinded raters. Case records were reviewed.

RESULTS

Of 1334 paired serum and CSF-OCB requests, 945 cases had sufficient clinical information. More than 1 CSF-OCB was detected in 268/945(28%) cases. Of these, 252 had ≥2 and 230 had ≥3 CSF-OCBs. The sensitivity and specificity for MS with ≥2 and ≥3 CSF-OCBs were 91.7%, 91.2%, 90.2% and 93.8% respectively. Only 3/22 patients with 2 CSF-OCBs had MS. In 25% of patients, CSF-OCBs reduced time to MS diagnosis (median 437.5 days (28-1332)).

CONCLUSION

Although cut-offs of ≥2 or ≥3 CSF-OCBs performed similarly well, 2 CSF-OCBs were frequently seen with non-inflammatory pathology. Use of ≥3 CSF-OCBs for MS diagnosis should be considered. CSF analysis reduced time to MS diagnosis by approximately 14 months.

Immune profiling in multiple sclerosis: a single-center study of 65 cytokines, chemokines, and related molecules in cerebrospinal fluid and serum

Introduction

The understanding of the pathophysiology of multiple sclerosis (MS) has evolved alongside the characterization of cytokines and chemokines in cerebrospinal fluid (CSF) and serum. However, the complex interplay of pro- and anti-inflammatory cytokines and chemokines in different body fluids in people with MS (pwMS) and their association with disease progression is still not well understood and needs further investigation. Therefore, the aim of this study was to profile a total of 65 cytokines, chemokines, and related molecules in paired serum and CSF samples of pwMS at disease onset.

Methods

Multiplex bead-based assays were performed and baseline routine laboratory diagnostics, magnetic resonance imaging (MRI), and clinical characteristics were assessed. Of 44 participants included, 40 had a relapsing-remitting disease course and four a primary progressive MS.

Results

There were 29 cytokines and chemokines that were significantly higher in CSF and 15 in serum. Statistically significant associations with moderate effect sizes were found for 34 of 65 analytes with sex, age, CSF, and MRI parameters and disease progression.

Discussion

In conclusion, this study provides data on the distribution of 65 different cytokines, chemokines, and related molecules in CSF and serum in newly diagnosed pwMS.

Diagnostic significance of IgG and albumin indices versus oligoclonal band types in demyelinating disorders

AIMS

The laboratory diagnosis of demyelinating inflammatory disorders (DIDs) relies on both intrathecal oligoclonal band (OCB) positivity and IgG index. Although OCB typing remains the gold-standard test for DIDs, it can be laborious and ambiguous, complicating diagnostics, and unduly increasing diagnostic time. We examined whether serum or cerebrospinal fluid (CSF) parameters can classify OCB types and, thus, be used as a replacement test to standard OCB typing.

METHODS

We retrospectively analysed >1000 prospectively collected samples of patients with DIDs and quantified albumin and IgG levels in the CSF and serum. We determined OCB types by isoelectric focusing combined with immunofixation and evaluated the diagnostic accuracies of IgG and albumin indices in discriminating OCB types by receiver operating characteristic curves and multinomial regression.

RESULTS

An IgG index cut-off of 0.589 differentiated types 2/3 from types 1/4 (area under the curve 0.780, 95% CI 0.761 to 0.812, p<0.001; specificity: 71.10%, sensitivity: 73.45%). Albumin quotient cut-off values of 6.625 and of 6.707 discriminated type 1 from type 4 and type 2 from type 3, respectively (specificity: <55%, sensitivity: <75%). Female sex, age, IgG index, CSF IgG and serum albumin were associated with different OCB types.

CONCLUSIONS

Our study reveals that IgG and albumin index can differentiate OCB types with adequate accuracy, especially if refined by age and gender.

Cerebrospinal fluid kappa free light chains for the diagnosis of multiple sclerosis: A consensus statement

Cerebrospinal fluid (CSF) analysis is of utmost importance for diagnosis and differential diagnosis of patients with suspected multiple sclerosis (MS). Evidence of intrathecal immunoglobulin G (IgG) synthesis proves the inflammatory nature of the disease, increases diagnostic certainty and substitutes for dissemination in time according to current diagnostic criteria. The gold standard to determine intrathecal IgG synthesis is the detection of CSF-restricted oligoclonal bands (OCBs). However, advances in laboratory methods brought up κ-free light chains (FLCs) as a new biomarker, which are produced in excess over intact immunoglobulins and accumulate in CSF in the case of central nervous system-derived inflammation. Overwhelming evidence showed a high diagnostic accuracy of intrathecal κ-FLC synthesis in MS with sensitivity and specificity of approximately 90% similar to OCB. κ-FLCs have advantages as its detection is fast, easy, cost-effective, reliable, rater-independent and returning quantitative results which might also improve the value of predicting MS disease activity. An international panel of experts in MS and CSF diagnostics developed a consensus of all participants. Six recommendations are given for establishing standard CSF evaluation in patients suspected of having MS. The panel recommended to include intrathecal κ-FLC synthesis in the next revision of MS diagnostic criteria as an additional tool to measure intrathecal immunoglobulin synthesis.

Cut-off evaluation of intrathecal oligoclonal bands of IgM in relapsing-remitting multiple sclerosis; a retrospective study

BACKGROUND

Multiple sclerosis (MS) is the most common demyelinating disease and characterized by immunological changes. Oligoclonal bands of IgG in CSF not seen in corresponding serum have been used for many years as part of the diagnostic criteria. However, considerably less is known about the role of IgM, despite several studies showing marked changes to IgM metabolism in MS. Bands of oligoclonal IgM (o-IgM) are more difficult to determine than oligoclonal IgG, thus limiting their study, and there is no agreement as to whether o-IgM in CSF should be part of the clinical work-up of MS. Nevertheless, there is a possibility that such bands might provide a prognostic marker if a cut-off could be established.

MATERIALS AND METHODS

In this pilot study, paired samples of CSF and serum from 37 patients with relapsing-remitting MS (RRMS) and 57 controls with no subsequent signs of neurological disease were analysed for total IgM, and bands of o-IgM were visualised by isoelectric focusing and western blot. Patient records were used to compare mean changes in Expanded Disability Status Scale (EDSS) over a maximum of 17 years.

RESULTS

None of the controls displayed extra o-IgM in CSF compared to corresponding serum, whereas additional o-IgM band(s) were seen in CSF in most patient samples (70%). After five years of disease, there was a significant difference in the EDSS between patients with no extra o-IgM compared to patients with at least one extra o-IgM band. This difference increased over time. If a cut-off of two or more extra bands of o-IgM in CSF was applied, this difference was not found.

CONCLUSION

These exploratory data suggest that o-IgM support the prognostic potential for RRMS, and though tentative, the occurrence of any bands of o-IgM restricted to CSF seems to result in poorer prognosis. Despite the small size of the groups, the data infer that the absence of CSF-restricted o-IgM is good news for the patient. The results need to be reproduced in a more comprehensive study.

A New Laboratory Workflow Integrating the Free Light Chains Kappa Quotient into Routine CSF Analysis

We performed this cohort study to test whether further analysis of intrathecal inflammation can be omitted if the free light chain kappa (FLCκ) quotient is within the reference range in the corresponding quotient diagram. FLCκ concentrations were measured in serum and cerebrospinal fluid (CSF) samples. The intrathecal fraction (IF) of FLCκ was calculated in relation to the hyperbolic reference range. 679 patient samples were used as a discovery cohort (DC). The sensitivity and negative predictive value (NPV) of the FLCκ-IF for the detection of an intrathecal humoral immune response (CSF-specific OCB and/or IF IgG/A/M > 0%) was determined. Based on these data, a diagnostic algorithm was developed and prospectively validated in an independent validation cohort (VC, n = 278). The sensitivity of the FLCκ-IF was 98% in the DC and 97% in the VC with a corresponding NPV of 99%. The use of the FLCκ-IF as a first line analysis would have reduced the Ig and OCB analysis by 62% in the DC and 74% in the VC. The absence of a FLCκ-IF predicts the absence of a humoral intrathecal immune response with a very high NPV of 99%. Thus, integration of our proposed algorithm into routine CSF laboratory analysis could help to reduce analytical efforts.

The Interpretation of Mirror Pattern Bands During Oligoclonal Immunoglobulin Isoelectric Focusing Electrophoresis: A Retrospective Study

Objective

Mirror patterns are incidental types that accompany the analysis of the oligoclonal band (OCB) in cerebrospinal fluid (CSF). However, their interpretation remains controversial. In this study, we analyzed all graphic results of mirror patterns from 86 patients to provide an optimal interpretation scheme for mirror patterns.

Methods

Matched CSF and serum specimens were obtained from patients with various neurological disorders that required OCB analysis. A total of 86 patients were screened and serum immunofixation electrophoresis (IFE) was performed in all 86. The interobserver agreement for interpreting mirror patterns by visual inspection was tested. The method agreement between the visual inspection and IFE was also evaluated. The CSF/serum albumin quotient (QALB) was calculated to determine the blood-brain barrier integrity of all patients.

Results

Of the 86 patients with mirror patterns, 19.8% (17/86) had typical mirror bands and most (80.2%) had atypical mirror bands. There was a good agreement between the 2 observers in interpreting typical mirror patterns. However, kappa statistics analysis showed poor agreement regarding the interpretation of atypical mirror bands by visual observation alone (kappa value, −0.026 to 0.314 between 2 observers). The disagreement was pronounced between the visual inspection and validation of IFE (kappa value, −0.0238 to 0.176 between the first observer and IFE; −0.322 to 0.118 between the second observer and IFE). The normal QALB rates in the type V groups were significantly higher than those in the type IV group and the positive QALB rates in the type IV were significantly higher than those in the type V.

Conclusion

Visual inspection to interpret mirror pattern bands is unreliable. Considering the completely different clinical significance between type IV and type V and high risk of potential misinterpretations, it is necessary to perform IFE on all the atypical mirror types to discriminate atypical type IV from atypical type V.

Intrathecal B cell-related markers for an optimized biological investigation of multiple sclerosis patients

In multiple sclerosis (MS) disease, the importance of the intrathecal B cell response classically revealed as IgG oligoclonal bands (OCB) in cerebrospinal fluid (CSF) was reaffirmed again in the recently revised diagnostic criteria. We aimed to optimize Laboratory investigation by testing the performance of new B cell-related molecules in CSF (Ig free light chains (FLCκ and λ) and CXCL13 (B-Cell Attracting chemokine1)) for MS diagnosis. 320 paired (CSF-serum) samples were collected from 160 patients with MS (n = 82) and non-MS diseases (n = 78). All patients benefited from IgG index determination, OCB detection, CSF CXCL13 and FLC (κ and λ) measurement in CSF and serum for metrics calculation (κ/λ ratio, FLC-related indexes, and κFLC-intrathecal fraction (IF)). CXCL13 and FLC metrics in CSF were higher in patients with MS and positive OCB. As expected, κFLC metrics—in particular, κFLC index and κFLC IF—had the highest accuracy for MS diagnosis. κ index showed the best performance (sensitivity 83% and specificity 91.7%) at a cut-off of 14.9. Most of the FLC-related parameters were positively correlated with IgG index and the level of CXCL13. In conclusion, the quantitative, standardizable, and technically simple CSF FLCκ metrics seem to be reliable for MS diagnosis, but could not replace OCB detection. CXCL13 appears to be an effective parameter reflecting the intrathecal B cell response. An optimized way for CSF testing combining the conventional and the new B cell-related parameters is proposed in this study.

Evidence for an Intrathecal Immunoglobulin Synthesis by Kappa Free Light Chains in Neurological Patients with an Isolated Band in Isoelectric Focusing

The gold standard for detecting intrathecal immunoglobulin synthesis is the determination of the oligoclonal band (OCB) in the cerebrospinal fluid (CSF) using isoelectric focusing (IEF). Controversy still exists regarding the significance of an isolated band in the CSF. A highly promising alternative method for the assessment of intrathecal inflammation is the quantification of kappa free light chains (k-FLC). Our aim was to evaluate the clinical significance of quantitative k-FLC in patients with an isolated band in the CSF. Using the Human Kappa Freelite Mx Kit on a turbidimetric Optilite®, we quantified the k-FLCs in paired CSF and serum samples in 47 patients with a single band in IEF. We classified patients into 27× inflammatory neurological disorders (IND), 2× peripheral inflammatory neurological disorders (PIND), 9× non-inflammatory neurological disorders (NIND) and 9× symptomatic controls (SC) based on their medical diagnosis. k-FLC were below the lower measurement limit of the analyser (LML) in all SC and PIND, as well as in 8 out of 9 NIND and 11 IND. Only 1 NIND and 16 IND were above the LML, and of these, only 14 IND were above the upper discrimination limit (Qlim). A neuroinflammatory nature of the diseases can be indicated in many cases by positive k-FLC in patients with an isolated band in IEF. The measurement of k-FLC can support the diagnosis of neurological diseases if they are included in the routine work-up.

Progressive Multiple Sclerosis

PURPOSE OF REVIEW

This article provides an update on progressive forms of multiple sclerosis (MS) commonly referred to as primary progressive MS and secondary progressive MS. It discusses the importance of diagnosing and detecting progression early, the similarities between progressive forms, challenges in detecting progression, factors that could augment progression, and the importance of disease-modifying therapies in patients with evidence of active progressive MS. It also discusses the overall care of progressive MS.

RECENT FINDINGS

The pathogenesis of primary progressive MS and secondary progressive MS is overlapping, and in both presentations, patients with relapses or focal MRI activity are classified as having active, progressive MS. All currently approved disease-modifying therapies are indicated for active secondary progressive MS. The therapeutic opportunity of anti-inflammatory drugs for the treatment of progressive MS is enhanced in those who are younger and have a shorter disease duration. Vascular comorbidities may contribute to progression in MS.

SUMMARY

Several challenges remain in the diagnosis, follow-up, and treatment of progressive MS. Early identification of active progressive MS is needed to maximize treatment benefit. The advantages of optimal comorbidity management (eg, hypertension, hyperlipidemia) in delaying progression are uncertain. Clinical care guidelines for advanced, severe MS are lacking.

CSF Kappa Free Light Chains: Cutoff Validation for Diagnosing Multiple Sclerosis

OBJECTIVE

To determine and validate a cerebrospinal fluid (CSF) κ (KCSF) value statistically comparable to detection of CSF-specific oligoclonal bands (OCB) to support the diagnosis of multiple sclerosis (MS).

PATIENTS AND METHODS

A total of 702 retrospective and 657 prospective paired CSF/serum samples from residual waste samples of physician-ordered OCB tests were obtained and tested for KCSF at Mayo Clinic. Charts were reviewed by a neurologist blinded to KCSF results. Specificity and sensitivity for MS diagnosis were evaluated to establish a diagnostic cutoff value for KCSF in the retrospective cohort and then validated in the prospective cohort.

RESULTS

Retrospective and prospective subgroups, respectively, included MS (n=85, 70), non-MS (n=615, 585), and undetermined diagnosis (excluded, n=2, 2). The retrospective data established a KCSF cutoff value of 0.1 mg/dL to be comparable to OCB testing. In the retrospective subgroup, KCSF vs OCB sensitivities for diagnosis of MS were 68.2% vs 75.0% (P=.08) and specificities were 86.1% vs 87.6% (P=.27). The KCSF area under the receiver operating characteristic curve was 0.772 (95% CI, 0.720 to 0.824), and for OCB was 0.813 (95% CI, 0.764 to 0.861). The prospective cohort was then used to validate the diagnostic KCSF value of 0.1 mg/dL; KCSF vs OCB sensitivities were 78.6% for both (P>.99) and specificities were 87.1% vs 89.4% (P=.09).

CONCLUSION

The KCSF value of 0.1 mg/dL is a valid alternative to OCB testing, offering a standardized quantitative measure, eliminating human error, reducing cost and turnaround time, with no significant difference in sensitivity and specificity. This study provides class I evidence that a KCSF value of 0.1 mg/dL can be used in place of OCB testing to support the diagnosis of MS.

Cerebrospinal fluid kappa free light chains as biomarker in multiple sclerosis—from diagnosis to prediction of disease activity

Multiple sclerosis (MS) is a chronic immune-mediated disorder of the central nervous system that shows a high interindividual heterogeneity, which frequently poses challenges regarding diagnosis and prediction of disease activity. In this context, evidence of intrathecal inflammation provides an important information and might be captured by kappa free light chains (κ-FLC) in the cerebrospinal fluid (CSF). In this review, we provide an overview on what is currently known about κ‑FLC, its historical development, the available assays and current evidence on its diagnostic and prognostic value in MS. Briefly, intrathecal κ‑FLC synthesis reaches similar diagnostic accuracy compared to the well-established CSF-restricted oligoclonal bands (OCB) to identify patients with MS, and recent studies even depict its value for prediction of early MS disease activity. Furthermore, detection of κ‑FLC has significant methodological advantages in comparison to OCB detection.

Determination of CSF GFAP, CCN5, and vWF Levels Enhances the Diagnostic Accuracy of Clinically Defined MS From Non-MS Patients With CSF Oligoclonal Bands

Background

Inclusion of cerebrospinal fluid (CSF) oligoclonal IgG bands (OCGB) in the revised McDonald criteria increases the sensitivity of diagnosis when dissemination in time (DIT) cannot be proven. While OCGB negative patients are unlikely to develop clinically definite (CD) MS, OCGB positivity may lead to an erroneous diagnosis in conditions that present similarly, such as neuromyelitis optica spectrum disorders (NMOSD) or neurosarcoidosis.

Objective

To identify specific, OCGB-complementary, biomarkers to improve diagnostic accuracy in OCGB positive patients.

Methods

We analysed the CSF metabolome and proteome of CDMS (n=41) and confirmed non-MS patients (n=64) comprising a range of CNS conditions routinely encountered in neurology clinics.

Results

OCGB discriminated between CDMS and non-MS with high sensitivity (85%), but low specificity (67%), as previously described. Machine learning methods revealed CCN5 levels provide greater accuracy, sensitivity, and specificity than OCGB (79%, +5%; 90%, +5%; and 72%, +5% respectively) while glial fibrillary acidic protein (GFAP) identified CDMS with 100% specificity (+33%). A multiomics approach improved accuracy further to 90% (+16%).

Conclusion

The measurement of a few additional CSF biomarkers could be used to complement OCGB and improve the specificity of MS diagnosis when clinical and radiological evidence of DIT is absent.

Cerebrospinal Fluid Findings in 541 Patients With Clinically Isolated Syndrome and Multiple Sclerosis: A Monocentric Study

Background

Reports on typical routine cerebrospinal fluid (CSF) findings are outdated owing to novel reference limits (RL) and revised diagnostic criteria of Multiple Sclerosis (MS).

Objective

To assess routine CSF parameters in MS patients and the frequency of pathologic findings by applying novel RL.

Methods

CSF white blood cells (WBC), CSF total protein (CSF-TP), CSF/serum albumin quotient (Q_alb), intrathecal synthesis of immunoglobulins (Ig) A, M and G, oligoclonal IgG bands (OCB) were determined in patients with clinically isolated syndrome (CIS) and MS.

Results

Of 541 patients 54% showed CSF pleocytosis with a WBC count up to 40/μl. CSF cytology revealed lymphocytes, monocytes and neutrophils in 99%, 41% and 9% of patients. CSF-TP and Q_alb were increased in 19% and 7% applying age-corrected RL as opposed to 34% and 26% with conventional RL. Quantitative intrathecal IgG, IgA and IgM synthesis were present in 65%, 14% and 21%; OCB in 95% of patients. WBC were higher in relapsing than progressive MS and predicted, together with monocytes, the conversion from CIS to clinically definite MS. Intrathecal IgG fraction was highest in secondary progressive MS.

Conclusions

CSF profile in MS varies across disease courses. Blood-CSF-barrier dysfunction and intrathecal IgA/IgM synthesis are less frequent when the novel RL are applied.

Kappa-Free Light Chains in CSF Predict Early Multiple Sclerosis Disease Activity

Objective

To investigate whether κ-free light chain (κ-FLC) index predicts multiple sclerosis (MS) disease activity independent of demographics, clinical characteristics, and MRI findings.

Methods

Patients with early MS who had CSF and serum sampling at disease onset were followed for 4 years. At baseline, age, sex, type of symptoms, corticosteroid treatment, and number of T2 hyperintense (T2L) and contrast-enhancing T1 lesions (CELs) on MRI were determined. During follow-up, the occurrence of a second clinical attack and start of disease-modifying therapy (DMT) were registered. κ-FLCs were measured by nephelometry, and κ-FLC index calculated as [CSF κ-FLC/serum κ-FLC]/albumin quotient.

Results

A total of 88 patients at a mean age of 33 ± 10 years and female predominance of 68% were included; 38 (43%) patients experienced a second clinical attack during follow-up. In multivariate Cox regression analysis adjusting for age, sex, T2L, CEL, disease and follow-up duration, administration of corticosteroids at baseline and DMT during follow-up revealed that κ-FLC index predicts time to second clinical attack. Patients with κ-FLC index >100 (median value 147) at baseline had a twice as high probability for a second clinical attack within 12 months than patients with low κ-FLC index (median 28); within 24 months, the chance in patients with high κ-FLC index was 4 times as high as in patients with low κ-FLC index. The median time to second attack was 11 months in patients with high κ-FLC index whereas 36 months in those with low κ-FLC index.

Conclusion

High κ-FLC index predicts early MS disease activity.

Classification of Evidence

This study provides Class II evidence that in patients with early MS, high κ-FLC index is an independent risk factor for early second clinical attack.

Clinical significance of a single cerebrospinal fluid immunoglobulin band: A retrospective study

BACKGROUND

To demonstrate an inflammatory process in the central nervous system, the presence of at least two immunoglobulin (Ig) bands in the cerebrospinal fluid (CSF) is required. So far, the presence of a single abnormal Ig band is considered as negative.

OBJECTIVE

The objective was to assess retrospectively the significance of a single CSF Ig band in clinical practice.

METHODS AND RESULTS

Out of 10,286 CSF analyses, we retained 214 results with single Ig. An inflammatory neurological disorder was diagnosed in 41% of patients.

CONCLUSION

Despite a modest sensitivity, the presence of a single CSF Ig band may be a biomarker of an inflammatory mechanism and, as such, may prompt the clinician to repeat the analysis when the clinical context remains suggestive.

Constitutional Mismatch Repair Deficiency Syndrome in a patient from India

This report highlights an extremely rare genetic condition constitutional mismatch repair deficiency (CMMRD) in an Indian pediatric patient with dual malignancies, who suffered from transient encephalopathy, a rare side effect of the drug Nivolumab and the associated challenge during CSF protein electrophoresis interpretation.

Cerebrospinal fluid oligoclonal bands in Neuroborreliosis are specific for Borrelia burgdorferi

Background

Cerebrospinal fluid (CSF) oligoclonal bands (OCB) occur in chronic or post-acute phase of inflammatory diseases of the central nervous system.

Objective

To determine whether CSF OCB in patients with neuroborreliosis (NB) are specific for borrelia burgdorferi senso lato.

Methods

We performed isoelectric focusing followed by immunoblotting in CSF of 10 NB patients and 11 controls (7 patients with multiple sclerosis, 2 patients with neuromyelitis optica spectrum disease, 1 patient with dementia and 1 patient with monoclonal gammopathy). Immunoblotting was performed using an uncoated as well as a borrelia antigen pre-coated nitrocellulose membrane (NCM). OCB were counted by visual inspection and photometric analysis. OCB were compared between uncoated und pre-coated NCM both in the NB and control group. For validation purposes inter-assay precision was determined by calculating the coefficient of variation (CV)

Results

Borrelia-specific OCB were found in the CSF of 9 NB patients and in none of the control subjects resulting in a sensitivity of 90% and a specificity of 100%. Number of NB specific OCB were 11±7 bands by photometric analyses compared to 9±5 bands by visual inspection. Validation experiments revealed an inconsistent inter-assay precision between visual and photometric analyses (NB uncoated: visual 28% versus photometric 14%, control subject uncoated: visual 16% versus photometric 24%).

Conclusions

In CSF samples with positive OCB, Borrelia-specific bands were detected in almost all NB patients and in none of the control subjects. Inconsistent inter-assay precision may be explained by a poor comparability of visual and photometric approach.

Kappa Free Light Chains and IgG Combined in a Novel Algorithm for the Detection of Multiple Sclerosis

Background: It is well known that the cerebrospinal fluid (CSF) concentrations of free light chains (FLC) and immunoglobulin G (IgG) are elevated in multiple sclerosis patients (MS). Therefore, in this study we aimed to develop a model based on the concentrations of free light chains and IgG to predict multiple sclerosis. We tried to evaluate the diagnostic usefulness of the novel κIgG index and λIgG index, here presented for the first time, and compare them with the κFLC index and the λFLC index in multiple sclerosis patients. Methods: CSF and serum samples were obtained from 76 subjects who underwent lumbar puncture for diagnostic purposes and, as a result, were divided into two groups: patients with multiple sclerosis (n = 34) and patients with other neurological disorders (control group; n = 42). The samples were analyzed using turbidimetry and isoelectric focusing. The κIgG index, λIgG index, κFLC index, and λFLC index were calculated using specific formulas. Results: The concentrations of CSF κFLC, CSF λFLC, and serum κFLC and the values of κFLC index, λFLC index, and κIgG index were significantly higher in patients with multiple sclerosis compared to controls. CSF κFLC concentration and the values of κFLC index, λFLC index, and κIgG index differed in patients depending on their pattern type of oligoclonal bands. κFLC concentration was significantly higher in patients with pattern type 2 and type 3 in comparison to those with pattern type 1 and type 4. The κFLC index, λFLC index, and κIgG index were significantly higher in patients with pattern type 2 in comparison to those with pattern type 4. The κFLC index and κIgG index were significantly higher in patients with pattern type 2 in comparison to those with pattern type 1, and in patients with pattern type 3 compared to those with pattern type 4. The κIgG index was markedly elevated in patients with pattern type 3 compared to those with pattern type 1. In the total study group, κFLC, λFLC, κFLC index, λFLC index, κIgG index, and λIgG index correlated with each other. The κIgG index showed the highest diagnostic power (area under the curve, AUC) in the detection of multiple sclerosis. The κFLC index and κIgG index showed the highest diagnostic sensitivity, and the κIgG index presented the highest ability to exclude multiple sclerosis. Conclusion: This study provides novel information about the diagnostic significance of four markers combined in the κIgG index. More investigations in larger study groups are needed to confirm that the κIgG index can reflect the intrathecal synthesis of immunoglobulins and may improve the diagnosis of multiple sclerosis.

Cerebrospinal fluid oligoclonal IgM test in routine practice: Comparison with quantitative assessment of intrathecal IgM synthesis

BACKGROUND

Intrathecal IgM synthesis demonstrated either as cerebrospinal fluid (CSF)-restricted oligoclonal (o-) IgM bands or calculated using various formulas has been linked to more aggressive multiple sclerosis (MS) course. However, the proportion of MS patients showing intrathecal IgM synthesis varies largely between studies. We aimed to explore the relation between different formulas and results of o-IgM, and to assess the frequency of o-IgM bands in an unselected series of samples.

METHODS

432 samples were analyzed for o-IgM, o-IgG and quantitative measures of IgM and IgG synthesis. IgM index and formulas of Reiber, Auer and Öhman were compared to the result of the o-IgM test.

RESULTS

At the cut-off commonly used, the non-linear formulas for intrathecal synthesis were specific (>94%) but rather insensitive (<40% even at a cut-off of 4 CSF-restricted bands) compared to o-IgM. No significant difference was noted in the performance of different formulas. At a cut-off of 4 bands, 61% of MS patients, but none of the controls were positive for o-IgM.

CONCLUSIONS

Formulas for intrathecal IgM synthesis are insensitive compared to o-IgM. We propose to evaluate samples with 2 or 3 extra-CSF IgM bands as borderline and only samples with 4 or more as definitely positive.

Diagnostic value of kappa free light chains in patients with one isolated band in isoelectric focusing

OBJECTIVES

Oligoclonal band (OCB) determination in cerebrospinal fluid (CSF) is the gold standard to detect intrathecal inflammation. However, there is uncertainty about the significance of one isolated band in CSF. Free light chains kappa (FLC-k) are gaining interest as a complementary method to detect intrathecal inflammation. The aim of this study was to investigate the performance of an additive measurement of FLC-k in patients with one isolated band in CSF.

MATERIALS & METHODS

FLC-k were analyzed using the nephelometric Siemens FLC-k kit in paired samples of CSF and sera (n = 56) in patients with one isolated band in isoelectric focusing. According to medical diagnosis, samples were subdivided in inflammatory neurological disease, non-inflammatory neurological disease controls and symptomatic controls. Intrathecal fraction of FLC-k was plotted in a FLC-k quotient diagram. OCB interpretation was done blinded by three experienced raters.

RESULTS

Of 6695 OCB analyses, 91 (1.4%) had one isolated band in CSF. After exclusion of patient samples due to unclear OCB pattern after reevaluation and sample availability, 56 patient samples were included in the study. All patients with an inflammatory origin of disease (n = 13) had FLC-k values above the upper discrimination line (Qlim) in the FLC-k quotient diagram, resulting in a sensitivity of 100% with a positive predictive value of 52% and a negative predictive value of 100%. Fourteen patients (36%) with a non-inflammatory origin of disease (n = 39) had FLC-k values above Qlim.

CONCLUSIONS

In patients with one isolated band in CSF, a lack of intrathecal fraction of FLC-k strongly favors a non-inflammatory orgin of disease. Implementation of FLC-k measurement can help the clinician in the diagnostic process of neurological diseases.