Humoral Immunity In Multiple Sclerosis

T-Cell-Mediated Immunity has dominated studies of Multiple Sclerosis (MS) pathogenesis, mainly due to detection of activated T-Cells in MS lesions, and analogies with the animal model Experimental Allergic Encephalomyelitis.

The prevailing Etiological hypothesis is that MS is a multifactorial disorder, affecting individuals predisposed by a combination of susceptibility Genes and environmental factors.

Plaque formation is attributed to Immune mechanisms, triggered by an AutoImmune attack directed against Antigens in the Myelin membrane.

This article reviews the roles of components of the Immune Response in MS including B-Cells, the Complement Cascade, AntiBodies and Genes.

Evidence suggests that B-Cell clonal expansion in CerebroSpinal Fluid and plaques of MS patients indicate an ongoing, Antigen-driven response in the Central Nervous System.

That MS is an AutoImmune Disease remains inconclusive, but the assumption is that Humoral Immunity plays a role in Lesion formation and perpetuation, or is involved in tissue-repair mechanisms.

The paradigm of MS as a T-Cell Disease must be revisited, as B-Cells are involved during the initial and later disease stages, and evidence is mounting for a 'degenerative process', in addition to (and possibly even preceding) Inflammation.

AntiBodies against Myelin Oligodendrocyte Glycoprotein (MOG) mediate DeMyelination in Experimental Autoimmune Encephalomyelitis (EAE) in different animal species and are implicated in the ImmunoPathogenesis of Multiple Sclerosis (MS).

In order to evaluate the AntiMOG response, we have analyzed the CerebroSpinal Fluids (CSFs) from 44 MS patients and 51 controls, 11 with Other Inflammatory Neurological Disorders (OIND) and 40 with Non-Inflammatory Neurological Disorders (NIND).

The frequency of Anti-MOG AntiBodies positive patients in the MS group (30%) was significantly higher compared to the NIND (8%, p=0.02), but not compared to the OIND group (55%, p=0.228).

Interestingly, all six patients with NeuroSarcoidosis had MOG-specific AntiBodies in their CSF. Frequency of Anti-MOG AntiBodies was similar in patients with clinically active and stable MS (32% and 26%, respectively; p=0.921).

However, in clinically active MS patients, AntiBody Titers were higher in comparison with patients with stable disease, although the difference did not reach the level of statistical significance (p=0.06).

These results further support the potential role of Anti-MOG AntiBodies in the ImmunoPathology of MS in the subset of patients with this disease.

Furthermore, our findings suggest for the first time that Anti-MOG AntiBodies could be an accessory diagnostic tool in NeuroSarcoidosis.

The development of somatically mutated Memory and Plasma B-Cells is a consequence of T-Cell-dependent Antigen-challenged Humoral Immunity.

To investigate the role of B-Cell-mediated Humoral Immunity in the initiation and evolution of Multiple Sclerosis (MS), we analyzed Ig variable heavy chain genes of Intrathecal B-Cells derived from patients with a first clinical manifestation suggestive of MS.

Sequences of Ig variable regions showed that B-Cells in the CerebroSpinal Fluid from most of these patients were clonally expanded and carried somatic hypermutated variable heavy chain genes.

The mutations showed a high replacement-to-silent ratio and were distributed in a way suggesting that these clonally expanded B-Cells had been positively selected through their Antigen Receptor.

In comparison, Intrathecal B-Cell clonal expansion often precedes both OligoClonal IgG Bands and multiple Magnetic Resonance Imaging lesions.

Clinical follow-up study showed that patients with clonally expanded Intrathecal B-Cells had a high rate of conversion to Clinically Definite MS.

The findings provide direct evidence of recruitment of germinal center differentiated B-Lymphocytes into the Central Nervous System during the initiation of MS.

These results indicate B-Cell-mediated Immune Response in the CerebroSpinal Fluid is an early event of inflammatory reaction in the Central Nervous System of MS.

This procedure also provides a more sensitive method to evaluate the association of Humoral Immunity in the evolution of MS.

Myelin Oligodendrocyte Glycoprotein (MOG) is found to induce both AutoReactive T-Cell and AntiBody responses associated with DeMyelinating pathology and is implicated in the pathogenesis of Multiple Sclerosis (MS).

In this study, we addressed the potential association of Anti-MOG Immune Responses with MS by examining, comparatively, both the T-Cell and AntiBody responses to recombinant MOG fragments in MS patients and healthy subjects.

T-Cells recognizing MOG were detected in MS patients as well as in healthy subjects, and their precursor frequency in the blood was not increased in patients with MS.

MOG-reactive T-Cells isolated from both MS patients and healthy subjects exhibited a similar Cytokine profile, producing InterLeukins (IL-4, IL-10) and Tumour Necrosis Factor (TNF), but not Interferon-gamma (IFN-γ).

And, recognized predominantly the ExtraCellular (residues 1-60) and the Transmembrane/Cytoplasmic (residues 154-218) domains of MOG.

In contrast, Anti-MOG AntiBodies derived from MS patients displayed a skewed reactivity pattern, even though the occurrence and Titers of Serum Anti-MOG AntiBodies were only slightly elevated in MS patients.

MS-derived AutoAntiBodies were predominantly directed at the 1-60 region of MOG, while naturally occurring AntiMOG AntiBodies derived from healthy individuals reacted selectively to the 154-218 domain.

These differences were statistically significant.

The findings of this study are consistent with the presence of Anti-MOG AntiBodies within DeMyelinating Lesions of MS and their role in the induction of DeMyelinating pathology in animal models.

The study has important implications in the understanding of the AutoImmune processes in MS.

The pathogenetic role of AutoAntiBodies in Multiple Sclerosis (MS) is uncertain. CD5⁺ B-Cells commonly produce AutoAntiBodies, but CD5 expression has also been implicated in B-Cell Tolerance.

We studied B-Cell subsets, AntiMyelin protein AntiBody-secreting cells in CerebroSpinal Fluid (CSF) and a panel of serum AutoAntiBodies in patients with Clinically Isolated Syndromes (CIS), suggestive of MS and patients with Clinically Definite MS (CDMS).

Patients with CDMS had a higher percentage of CD5- B-Cells in CSF than did control subjects (P = 0.02).

CIS patients with ImmunoGlobulin G (IgG) OligoClonal Bands in CSF or multiple lesions on Magnetic Resonance Imaging (MRI) had a higher percentage of CD5- B-Cells in CSF than did the remaining CIS patients (P = 0.03).

The percentage of CD5- and CD80⁺ B-Cells correlated positively and the percentage of CD5⁺ B-Cells correlated negatively with the number of CSF cells secreting AntiMyelin Basic Protein (Anti-MBP) AntiBodies.

The prevalence of Serum autoAntiBodies was comparable in the three patient groups.

We conclude that Intrathecal expansion of CD5- B-Cells appears to be more characteristic in MS patients, and CD5⁺ B-Cells may be associated with a lower prevalence of AntiMyelin AntiBody production.

Multiple Sclerosis (MS) is an Inflammatory Disease of the Central Nervous System with multifocal areas of DeMyelination.

Although its Etiology and Pathogenesis remain controversial, several lines of evidence indicate that MS is mediated by a misdirected Immune Response against one or several Myelin proteins.

The involvement of diverse Leukocyte subsets and their products in MS is still the subject of considerable debate.

The emphasis on T-Cells has derived mainly from the detection of activated T-Cells in MS Plaques and analogies with animal models of MS. Because of these observations Cell-Mediated Immunity has dominated the research field of MS to this day.

However, in recent years the role of B-Cells, Plasma Cells and ImmunoGlobulins in MS have been re-examined, and current findings indicate that Humoral Immunity also plays a major role in disease pathogenesis.

B-Cells and their products could exert several potential effects during the course of MS.

Firstly, AutoAntiBodies against specific Myelin Antigens could mediate damage to Myelin membranes.

Secondly, some studies suggest that natural AutoAntiBodies could enhance ReMyelination.

Thirdly, AntiBodies directed against Myelin components can participate in AntiIdiotypic Networks, which may regulate the course of MS.

Increased Intrathecal ImmunoGlobulin synthesis reflected by raised IgG indices and an OligoClonal pattern is the most common abnormality detected in MS patients.

The introduction of more sensitive procedures for protein detection has allowed demonstrating OligoClonal Bands (OCBs) in up to 95 % of patients with Clinically Definite MS.

Although the presence of OCBs in CSF of MS patients is now well established as a sensitive laboratory test to support the clinical diagnosis, OCBs may be present in other disorders, including those not directly related to infection or abnormal Immune Response.

Nevertheless, the pathogenesis of OCBs in MS is still obscure, and despite extensive research their Antigenic target(s) have yet to be established.

Therefore, a critical task is to identify the specificity of such target(s), thus providing significant clues about MS Etiology.

For this purpose, novel Molecular Immunologic Strategies have been recently developed to offer alternative approaches to identify putative Antigens recognized by AntiBodies present in MS patients.

The elucidation of the mechanisms and target(s) responsible for the onset of MS has obvious implications for the further development of specific therapies.

Identification of the causative agent of Multiple Sclerosis (MS) has long eluded investigators and has become the "Holy Grail" of researchers in the field.

The Immune Response in CerebroSpinal Fluid of patients with MS, indicated by an increased IgG level and the presence of specific OligoClonal Bands after ElectroPhoresis, strongly parallels that found in various infectious diseases of the Central Nervous System.

To understand the nature of B-Lymphocyte activation in MS, 4 laboratories studied the Antigen-Binding regions of AntiBodies found in MS Brain DeMyelinative plaques and CerebroSpinal Fluid.

Each analysis revealed:
1. Limited germline expression
   • Results not expected for a random Bystander Response
2. Features consistent with a specific Antigen-targeted process
3. The clonal expansion of populations of B-Lymphocytes in MS

The screening of libraries expressing protein products derived from chronic MS Plaque messenger RNA with AntiBodies purified from plaques, CerebroSpinal Fluid, or Serum of patients with MS has thus far not revealed the antigenic target(s) of the MS AntiBody Response.

Because putative MS Antigens could be in low abundance, the screening of large libraries of random Peptides expressed on phage surfaces might offer an alternative approach to identify Peptide sequences recognized by MS AntiBodies.

New sophisticated molecular Immunologic techniques described herein should enhance our ability to identify putative Antigen(s) targets in MS.

Although the presence of OligoClonal IgG with abnormal kappa/lambda light-chain ratio in Multiple Sclerosis (MS) has been known for many years, this finding has not been put to diagnostic use in most routine clinical laboratories.

In a retrospective study we report differences in the OligoClonal Banding patterns between Multiple Sclerosis and non-MS patients.

We had sufficient CerebroSpinal Fluid (CSF) on 36 from 71 patients with OligoClonal Bands for ImmunoFixation for kappa and lambda light chains, and for free kappa and free lambda.

Thirteen out of 14 patients with clinically confirmed MS had predominantly IgG (kappa) banding. In contrast, in seven out of eight patients with diagnoses other than MS the IgG was linked to both kappa and lambda light chains in approximately equal proportions.

Nine out of 14 patients with Probable/Possible/Suspected MS showed predominantly IgG (kappa) banding; five others in this group had both IgG (kappa) and IgG (lambda) and free lambda light chains.

The finding of IgG (kappa) Bands in CSF samples with OligoClonal Bands supports a diagnosis of MS.

Introduction
The Intrathecal response of IgG, is the most frequent NeuroPathological Sign in Multiple Sclerosis (MS) patients beside the detection of OligoClonal IgG Bands in CerebroSpinal Fluid (CSF).

At the same time the observation of an Intrathecal AntiBody synthesis (AntiBody Index) 1.4) against NeuroTropic Viruses like Measles, Rubella, Varicella Zoster or Herpes Simplex shows a higher frequency in MS than any other chronic disease (MRZH reaction).

We report the Intrathecal, polyspecific and OligoClonal Immune Response in patients with definitive MS.

Patients And Methods
CSF and Serum were tested for Albumin, IgG, IgM and IgA by standard ImmunoChemical Nephelometry assay while Virus specific AntiBodies in CSF and Serum samples were evaluated by ELISA and calculated as AntiBody index.

Results
OligoClonal IgG by, isoelectric focusing was detectable in all patients. A differential pattern of combined AntiBody index against NeuroTropic Virus was observed.

The largest frequency of a single species in the OligoClonal Immune Response was for Measles AntiBodies, while the AntiBody response was found as a combination with increased Rubella AntiBody index and VZ AntiBody index, respectively.

Conclusion
Our results although preliminary for our country, enrich the criteria about that MRZH reaction provide a major NeuroImmunological support to MS diagnosis.

We studied Intrathecal IgG synthesis and AutoAntiBody-secreting cells in 148 patients with Possible Onset Symptoms of MS (POSMS) or Clinically Definite MS (CDMS).

In POSMS Intrathecal synthesis of IgG OligoClonal Bands and abnormalities on T₂-weighted Magnetic Resonance Imaging were associated but the former were more prevalent.

The CerebroSpinal Fluid (CSF) Leukocyte count and the number of AntiProteoLipid Protein AntiBody-secreting cells in CerebroSpinal Fluid (CSF) correlated with disease activity in POSMS.

Intrathecal IgG synthesis levels and the number of Anti-Myelin Basic Protein AntiBody-secreting cells in CSF correlated with disease activity in CDMS.

Our results support recent reports of pathogenetic heterogeneity and a pathogenetic role of the AntiBody response in MS.

The presence of OligoClonal Bands in CerebroSpinal Fluid (CSF) in Multiple Sclerosis (MS) indicates a restricted heterogeneity of ImmunoGlobulin (Ig).

The portion of Myelin Basic Protein encompassing residues 80-96 contains Epitopes frequently recognized by T and B-Cells of MS patients.

To define further this restricted heterogeneity and to direct further efforts to identify an antigenic target of CSF OligoClonal Bands.

The presence of Idiotope (Id)-bearing AntiBodies sharing an Id with a murine MonoClonal AntiBody to Myelin Basic Protein Peptide 80-89 was examined in the CSF of MS patients.

CSF samples from 57 patients with Clinically Definite MS and 45 patients with Other Neurological Diseases were standardized for amount of IgG and analyzed by ImmunoBlotting for detection of Id-bearing AntiBodies.

Id-bearing Ig was detected in the CSF of 79% of MS patients and 16% of Other Neurological Disease patients. Further statistical analysis revealed:
1. 84% Specificity
2. 86% Positive predictive value
3. 76% Negative predictive value of the test
4. The probability a positive screening result indicated MS was 81%

Thus, AntiBodies containing a cross-reactive Id are present preferentially in the CSF of patients with MS compared with those with Other Neurological Diseases.

An Immune Network that has limited V region gene usage likely exists in the CSF and Central Nervous System of patients with MS and may provide evidence about Antigens relevant to the pathogenesis of MS.