Saliva Free Light Chains in Patients with Neuro-Sjögren.

Background: Sjögren's syndrome (SS) is an autoimmune disease characterized by sicca symptoms and various extra-glandular manifestations. The diagnosis of SS requires sicca symptoms, anti-SSA(Ro)-antibody positivity, and/or pathological focus scores on a minor salivary gland biopsy. Previous studies have investigated different biomarkers in order to avoid invasive diagnostic procedures. It was found that kappa and lambda free light chains (KFLC and LFLC) in saliva are specific for SS. Methods: FLC concentrations in saliva and serum were determined in 130 patients-50 with SS and neurological involvement (Neuro-Sjögren) and 80 neurological controls. The EULAR SS disease activity index and patient reported index (ESSPRI) were determined in patients with SS. Results: Patients with SS revealed increased pain and decreased saliva production according to the ESSPRI and Saxon test, respectively, with increasing FLC concentrations in the saliva. No significant differences in serum and salivary protein concentrations were observed between patients with SS and controls. Conclusion: KFLC and LFLC concentrations in saliva are not suitable to distinguish patients with Neuro-Sjögren and neurological control subjects, thus a diagnostic biopsy is still required. The association of salivary KFLC and LFLC concentrations with saliva production and ESSPRI pain score suggests a complex relationship between dryness and pain in patients with SS.

Stem Cell Therapy in Neuroimmunological Diseases and Its Potential Neuroimmunological Complications.

Background: Since the 1990s, transplantations of hematopoietic and mesenchymal stem cells (HSCT and MSCT) and dendritic cell (DCT) have been investigated for the treatment of neurological autoimmune disorders (NADs). With the growing number of transplanted patients, awareness of neuroimmunolgical complications has increased. Therefore, an overview of SCT for the most common NADs and reports of secondary immunity after SCT is provided. Methods: For this narrative review, a literature search of the PubMed database was performed. A total of 86 articles reporting on different SCTs in NADs and 61 articles dealing with immune-mediated neurological complications after SCT were included. For multiple sclerosis (MS), only registered trials and phase I/II or II studies were considered, whereas all available articles on other disorders were included. The different transplantation procedures and efficacy and safety data are presented. Results: In MS patients, beneficial effects of HSCT, MSCT, and DCT with a decrease in disability and stabilization of disease activity have been reported. These effects were also shown in other NADs mainly in case reports. In seven of 132 reported patients with immune-mediated neurological complications, the outcome was fatal. Conclusions: Phase III trials are ongoing for MS, but the role of SCT in other NADs is currently limited to refractory patients due to occasional serious complications.

Diagnostic Cerebrospinal Fluid Biomarker in Early and Late Onset Multiple Sclerosis.

Background: The intrathecal humoral response is the characteristic diagnostic finding in the cerebrospinal fluid (CSF) analysis of patients with multiple sclerosis (MS). Although the average age of MS patients increases, little is known about the sensitivity of diagnostic markers in elderly MS patients. Methods: In this retrospective two-center study, intrathecal free light chains kappa fraction (FLCk IF) and oligoclonal bands (OCB) were studied in a large cohort of patients with early and late onset relapsing (RMS) and progressive (PMS) MS. Furthermore, the humoral immune profile in CSF was analyzed, including the polyspecific intrathecal immune response measured as the MRZ reaction. Results: While the frequency of CSF-specific OCB did not differ between early and late onset RMS and PMS, the sensitivity of positive FLCk IF and absolute FLCk IF values were lower in PMS. The positivity of the MRZ reaction was equally frequent in early and late onset RMS and PMS. PMS patients had higher local IgA concentrations than RMS patients (p = 0.0123). Conclusions: OCB are slightly superior to FLCk IF in progressive MS in terms of sensitivity for detecting intrathecal immunoglobulin synthesis. The MRZ reaction, as the most specific parameter for MS, is also applicable in patients with late onset and progressive MS.

Kappa Free Light Chains in Cerebrospinal Fluid in Inflammatory and Non-Inflammatory Neurological Diseases.

BACKGROUND: Oligoclonal bands represent intrathecal immunoglobulin G (IgG) synthesis and play an important role in the diagnosis of multiple sclerosis (MS). Kappa free light chains (KFLC) are increasingly recognized as an additional biomarker for intrathecal Ig synthesis. However, there are limited data on KFLC in neurological diseases other than MS. METHODS: This study, conducted at two centers, retrospectively enrolled 346 non-MS patients. A total of 182 patients were diagnosed with non-inflammatory and 84 with inflammatory neurological diseases other than MS. A further 80 patients were classified as symptomatic controls. Intrathecal KFLC production was determined using different approaches: KFLC index, Reiber's diagram, Presslauer's exponential curve, and Senel's linear curve. RESULTS: Matching results of oligoclonal bands and KFLC (Reiber's diagram) were frequently observed (93%). The Reiber's diagram for KFLC detected intrathecal KFLC synthesis in an additional 7% of the patient samples investigated (4% non-inflammatory; 3% inflammatory), which was not found by oligoclonal band detection. CONCLUSIONS: The determination of both biomarkers (KFLC and oligoclonal bands) is recommended for routine diagnosis and differentiation of non-inflammatory and inflammatory neurological diseases. Due to the high sensitivity and physiological considerations, the assessment of KFLC in the Reiber's diagram should be preferred to other evaluation methods.

The Influence of the Ventricular-Lumbar Gradient on Cerebrospinal Fluid Analysis in Serial Samples.

BACKGROUND: Cerebrospinal fluid (CSF) samples from patients with non-inflammatory neurological diseases are used for control groups in biomarker studies. Since large amounts of CSF are withdrawn, patients with idiopathic intracranial hypertension (IIH) or normal pressure hydrocephalus (NPH) are especially suitable. The serially taken CSF portions are usually collected in different tubes. We aimed to investigate whether the later random choice of one of these tubes for CSF investigations might harbor the risk of different CSF protein findings due to the so-called ventriculo-lumbar CSF gradient. METHODS: Patients with IIH (9) and NPH (7) were included. CSF was serially taken and collected in six tubes of 5 mL each. Concentrations and CSF-serum quotients of immunoglobulins, albumin and the virus-specific antibody index (AI) were determined in the first, fourth and sixth CSF fraction. RESULTS: CSF immunoglobulin and albumin concentrations and CSF-serum protein quotients were significantly lower in the fourth and sixth CSF fraction compared with the first CSF fraction. Virus-specific AI did not significantly differ in the different CSF fractions. CONCLUSIONS: CSF protein analytics should be performed in the first CSF fraction in order to avoid different measurement results and achieve comparability within a control group and between different control and patient groups.

The Increasing Role of Kappa Free Light Chains in the Diagnosis of Multiple Sclerosis.

Free light chains (FLC) are a promising biomarker to detect intrathecal inflammation in patients with inflammatory central nervous system (CNS) diseases, including multiple sclerosis (MS). The diagnostic use of this biomarker, in particular the kappa isoform of FLC ("KFLC"), has been investigated for more than 40 years. Based on an extensive literature review, we found that an agreement on the correct method for evaluating KFLC concentrations has not yet been reached. KFLC indices with varying cut-off values and blood-CSF-barrier (QAlbumin) related non-linear formulas for KFLC interpretation have been investigated in several studies. All approaches revealed high diagnostic sensitivity and specificity compared with the oligoclonal bands, which are considered the gold standard for the detection of intrathecally synthesized immunoglobulins. Measurement of KFLC is fully automated, rater-independent, and has been shown to be stable against most pre-analytic influencing factors. In conclusion, the determination of KFLC represents a promising diagnostic approach to show intrathecal inflammation in neuroinflammatory diseases. Multicenter studies are needed to show the diagnostic sensitivity and specificity of KFLC in MS by using the latest McDonald criteria and appropriate, as well as standardized, cut-off values for KFLC concentrations, preferably considering non-linear formulas such as Reiber's diagram.

Evidence of Oligoclonal Bands Does Not Exclude Non-Inflammatory Neurological Diseases.

Cerebrospinal fluid analysis is an essential part of the diagnostic workup in various neurological disorders. Evidence of an intrathecal immunoglobulin synthesis, as demonstrated by Reiber's diagram or the more sensitive oligoclonal bands (OCB), are typical for neuroinflammatory diseases, and normally not expected in non-inflammatory neurological diseases. Therefore, patients with non-inflammatory neurological diseases are often used in control groups in studies investigating autoimmune diseases of the central nervous system. However, data about the frequency of intrathecal immunoglobulin synthesis in non-inflammatory neurological disease are scarce. The cerebrospinal fluid (CSF) records of a total of 3622 patients were screened and 2114 patients included with presumably non-inflammatory neurological diseases like dementia, idiopathic peripheral neuropathy, motoneuron disease, stroke, and epileptic seizures. Evidence of an intrathecal immunoglobulin synthesis can be found with low frequency also in non-inflammatory neurological diseases. A much higher rate of patients showed intrathecal immunoglobulin synthesis as demonstrated by OCB than by Reiber's diagram. In patients with disorders of the peripheral nervous system the frequency of OCB was much lower than in patients presenting with central nervous system manifestations. Evidence of an intrathecal immunoglobulin synthesis should not automatically lead to exclusion of non-inflammatory neurological diseases but should rather prompt the way to investigate for the origin of the intrathecal immunoglobulin synthesis.

The Impact of Immunomodulatory Treatment on Kappa Free Light Chains as Biomarker in Neuroinflammation.

BACKGROUND: Kappa free light chains (KFLC) are a promising new biomarker to detect neuroinflammation. Still, the impact of pre-analytical effects on KFLC concentrations was not investigated. METHODS: KFLC concentrations were measured in serum and cerebrospinal fluid (CSF) of patients with a newly diagnosed multiple sclerosis (MS) or clinically isolated syndrome (CIS) before (n = 42) or after therapy with high-dose methylprednisolone (n = 65). In prospective experiments, KFLC concentrations were analyzed in the same patients in serum before and after treatment with high-dose methylprednisolone (n = 16), plasma exchange (n = 12), immunoadsorption (n = 10), or intravenous immunoglobulins (n = 10). In addition, the influence of storage time, sample method, and contamination of CSF with blood were investigated. RESULTS: Patients diagnosed with MS/CIS and treated with methylprednisolone showed significantly lower KFLC concentrations in serum as untreated patients. Repeated longitudinal investigations revealed that serum KFLC concentrations continuously decreased after each application of methylprednisolone. In contrast, other immune therapies and further pre-analytical conditions did not influence KFLC concentrations. CONCLUSION: Our results show prominent effects of steroids on KFLC concentrations. In contrast, various other pre-analytical conditions did not influence KFLC concentrations, indicating the stability of this biomarker.

Severe Anti-N-Methyl-D-Aspartate Receptor Encephalitis Under Immunosuppression After Liver Transplantation.

Anti-NMDA receptor encephalitis is a rare and often therapy-responsive autoimmune disease that usually affects young adults and causes neuropsychiatric symptoms. Here, we describe a 69-year-old patient who developed anti-NMDA receptor encephalitis while being under adequate immunosuppressive therapy following liver transplantation. Although a broad spectrum of different immunotherapies was applied and anti-NMDA receptor antibody titers gradually decreased, the clinical course could not be affected positively. Autoimmune encephalitis after transplantation is only described in a few cases and not well-recognized. Our case adds further evidence for anti-NMDA receptor encephalitis as the cause of neuropsychiatric symptoms even under immunosuppressive therapy in a post-transplant setting.

The Persisting Significance of Oligoclonal Bands in the Dawning Era of Kappa Free Light Chains for the Diagnosis of Multiple Sclerosis.

The latest revision of the McDonald criteria of 2017 considers the evidence of an intrathecal immunoglobulin (IgG) synthesis as a diagnostic criterion for dissemination in time in multiple sclerosis. While the detection of oligoclonal bands is considered as the gold standard, determination of kappa free light chains might be a promising tool as a less technically demanding and cost saving method. However, data on the direct comparison between kappa free light chains and oligoclonal bands are limited and no study to date has used the highly sensitive method of polyacrylamide gels with consecutive silver staining for the demonstration of oligoclonal bands. Furthermore, the impact of the revised McDonald criteria of 2017 on the role of kappa free light chains as a biomarker has not been investigated. Nephelometry was used to determine kappa free light chains in cerebrospinal fluid (CSF) and serum from 149 patients with their first demyelinating event between 2010 and 2015. Clinical data, kappa free light chains, and oligoclonal band status were compared at the time of initial diagnosis and after follow-up to identify converters from clinically isolated syndrome to multiple sclerosis. An elevated kappa free light chain index (>5.9) was found in 79/83 patients (95%) with multiple sclerosis diagnosed at baseline, slightly less frequent than oligoclonal bands (98.8%). 18/25 (72%) patients who converted from clinically isolated syndrome to multiple sclerosis showed an elevated kappa free light chain index compared to 20/25 (80%) patients with positive oligoclonal bands. In patients with stable clinically isolated syndrome 7/41 (17%) displayed an elevated kappa free light chain index against 11/41 (27%) oligoclonal band positive patients. Only two patients with stable clinically isolated syndrome showed an elevated kappa free light chain index but were oligoclonal bands negative. In conclusion, determination of the kappa free light chain index is a promising diagnostic approach to assess intrathecal immunoglobulin synthesis in multiple sclerosis. Nevertheless, oligoclonal bands are highly prevalent in multiple sclerosis and can detect an intrathecal synthesis of IgG even when the kappa free light chain index is below the threshold. We consider sequential use of both methods as reasonable.