MRZH reaction increases sensitivity for intrathecal IgG synthesis in IgG Oligoclonal band negative Multiple Sclerosis patients

A review of laboratory practices for CSF oligoclonal banding and associated tests

Multiple sclerosis (MS) is a chronic autoimmune disorder affecting the central nervous system, often emerging in early adulthood and representing a leading cause of neurological disability in young adults. Diagnosing MS involves a combination of clinical assessment, imaging and laboratory tests, with cerebrospinal fluid (CSF)-specific immunoglobulin G (IgG) oligoclonal bands (OCB) being an important marker for fulfilling the dissemination in time criteria. A recent survey of Canadian clinical laboratories highlighted considerable variation in OCB reporting practices nationwide, spanning quality control (QC) practices, acceptable time limits between paired CSF and serum sample collections, protocols for reporting band counts, interpretation and reporting of mirrored patterns, testing panels, and interpretive thresholds. These inconsistencies impact patient care and the comparability of laboratory results across different laboratories. The Harmonized CSF Analysis for MS Investigation (hCAMI) subcommittee of the Canadian Society of Clinical Chemists Reference Interval Harmonization Working Group was established to generate recommendations for laboratory processes and reporting of CSF OCB and associated tests supporting MS diagnosis. This review serves as a foundation for these efforts, summarizing the available evidence in areas where practice variations have been noted. This review begins by examining current practices and guidelines for standardized quality assurance, including optimal QC materials, frequency, documentation, and participation in external quality assurance programs. The disparity between paired CSF and serum sample acceptability time limits was further examined by reviewing current practices and recommendations as well as compiling evidence on IgG synthesis, turnover rate, biological variation, and stability in CSF and serum samples. Additionally, this review addresses the lack of consensus on reporting the number of CSF-specific and CSF-serum matched bands, focusing on interpreter variability and clinical utility. Contributing factors and clinical implications of mirror patterns, including discussion on monoclonal gammopathies and cases of matched bands of differing staining intensity, is provided. Testing panel components including adjunctive CSF tests, such as the IgG index, to support MS investigations despite their absence from clinical guidelines is also discussed. This review also provides a comprehensive analysis of current practices, guidelines, and the evidence surrounding different cutoffs for IgG index and CSF-specific bands.

Finally, the review considers emerging biomarkers, such as the kappa free light chain index and serum neurofilament light chain, which show promise for MS diagnosis and management. This comprehensive review of current practices, guidelines, and evolving evidence will guide the hCAMI subcommittee's efforts to harmonize CSF OCB analysis and improve MS diagnosis.

Human endogenous retrovirus and multiple sclerosis: A review and transcriptome findings

Multiple Sclerosis is an autoimmune disease with an unknown etiology. Both genetic and environmental factors are believed to trigger MS autoimmunity. Among the environmental factors, infectious agents have been extensively investigated, and the Human Endogenous Retroviruses (HERVs), especially HERV-W, are believed to be associated with MS pathogenesis. HERVs are derived from ancestral infections and comprise around 8% of the human genome. Although most HERVs are silenced, retroviral genes may be expressed with virion formation. There is extensive evidence of the relationship between HERV-W and MS, including higher levels of HERV-W expression in MS patients, HERV-W protein detection in MS plaques, and the HERV-W env protein inducing an inflammatory response in in vitro and in vivo models. Here we discuss possible links of HERVs and the pathogenesis of MS and present new data regarding the diversity of HERVs expression in samples derived from MS patients.

Antibodies to Epstein-Barr virus and neurotropic viruses in multiple sclerosis and optic neuritis

Antibody indices to Measles, Mumps, Varicella Zoster (MRZ) are of diagnostic value in multiple sclerosis (MS). Here, we have investigated, if this panel could be extended to increase diagnostic value. Samples from relapsing-remitting (RR) MS and optic neuritis (ON) patients were tested for reactivity to antigens from Epstein-Barr, Varicella Zoster, Measles, Mumps and Rubella (EMMRZ) viruses. Increased IgG levels in serum and cerebrospinal fluid (CSF) were found in RRMS patients, along with a significant correlation between serum and CSF. The sensitivity of the EMMRZ panel was increased approximately 40% compared to the MRZ panel, suggesting that the EMMRZ panel may be useful in MS and ON diagnostics.

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

BACKGROUND

The presence of ≥3 oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) without corresponding bands in serum represents a definite pathological pattern, whereas the clinical significance of 1-2 CSF bands (borderline pattern) is poorly investigated.

METHODS

We screened 1986 consecutive CSF and serum samples which were collected over a four-year time period and had results of isoelectric focusing (IEF) available. Of patients with borderline OCB we reviewed individual medical charts for assessment of clinical diagnoses. Where feasible, IEF was replicated and results of follow-up samples were obtained. IEF was performed using polyacrylamide gel followed by immunoblotting and IgG-specific antibody staining. Additionally, we performed a systematic literature review of the diagnostic specificity of OCB using different cut-offs for CSF-restricted bands.

RESULTS

Out of 253 patients with borderline OCB, 21.7% had an inflammatory neurological disease (IND) of the central nervous system, comprising 4% multiple sclerosis patients, and 14.2% had a peripheral IND, whereas the remaining 64.1% of patients showed non-inflammatory diseases. Frequency of one or two CSF bands without corresponding serum bands did not differ between the disease groups. In a subgroup of 100 patients IEF was repeated. Of those, 73% were OCB negative, while no sample was positive. In 26 patients IEF results were available of a follow-up sample collected after a median of 27 months. Of those, 4 (15.4%) turned positive. Systematic literature review revealed a diagnostic specificity of OCB of 97% and 92% using a cut-off ≥3 and ≥2 CSF bands in patients with mainly non-inflammatory neurological diseases.

CONCLUSION

The clinical significance of one or two CSF-restricted bands is moderate and, hence, indicates a possible but not reliable proof of intrathecal B-cell activity. Sample re-testing, introduction of an additional diagnostic category, e.g. "possible intrathecal IgG synthesis", and follow-up lumbar puncture might be possible options to address this scenario.

The intrathecal polyspecific antiviral immune response (MRZ reaction): A potential cerebrospinal fluid marker for multiple sclerosis diagnosis

We tested the performance of MRZ-reaction, an intrathecal humoral immune response against-Measles (M), Rubella (R) and Varicella Zoster (Z) viruses, in multiple sclerosis (MS) diagnosis. The MRZ-reaction was significantly more positive in MS than in non-MS group with a specificity of 91.9%. In MS group, the RZ-profile was the most prevalent and the R-specific antibody-index was correlated to the number of oligoclonal bands (OCB) in CSF. Interestingly, the MRZ-reaction was detected in 53% of OCB-negative-MS patients. The MRZ-reaction seems to be a relevant CSF diagnostic marker of MS disease. The likely relation between its positivity and the vaccination status deserves to be investigated.