Monoclonal antibodies to streptococcal group A carbohydrate. II. The VK1GAC light chain is preferentially associated with serum IgG3

A kappa-light chain variable region (V kappa) dominantly employed in the serum antibody response of A/J mice to streptococcal group A carbohydrate (GAC) has been termed VK1GAC. Examination of in vitro recombinants between the isolated heavy and light chains of VK1GAC+ and VK1GAC-anti-GAC hybridomas and non-GAC-binding myeloma proteins indicated that two antisera (anti-Id5 and anti-Id20) recognized the VK1GAC light chain when it was free in solution or paired with several heterologous heavy chains. Screening of a panel of A/J anti-GAC monoclonal antibodies with these antisera showed almost complete concordance between Id5 and Id20 expression and the presence of VK1GAC light chain as detected by its unique isoelectric focusing spectrotype. These antisera were used to examine serum expression of the VK1GAC light chain in normal and hyperimmune serum of A/J mice. Normal A/J serum contained from 20 to 100 micrograms Id5/ml serum, whereas only 1 to 10 micrograms Id20/ml serum was detected. The levels of both VK1GAC idiotypes increased dramatically 10- to 20-fold after hyperimmunization of mice with group A vaccine. When serum IgG from normal and immune mice was fractionated into the IgG subclasses (IgG1, IgG2a, and IgG3), it was found that the VK1GAC light chain does not pair randomly with heavy chains of the IgG subclasses, but rather is associated preferentially with heavy chains of the IgG3 subclass whether or not it is associated with antibodies to GAC. These results suggest that the heavy chain pairing exhibited by this VK product may not be random.     

Th1/Th2 cytokine balance and nitric oxide in cerebrospinal fluid and serum from patients with multiple sclerosis

Tumor necrosis factor (TNF-alpha) and IL-10 are key regulators of the T helper (Th)1/Th2 balance, which is critically skewed in many pathological conditions including immune-mediated inflammatory diseases of central nervous system (CNS) such as multiple sclerosis (MS). Nitric oxide (NO) has been reported to have dual effects on CNS pathology, and to play an important role in MS. We performed a cross-sectional study in 17 randomly selected patients during MS flare-up, and compared levels of TNF-alpha, IL-10 and NO in serum and cerebrospinal fluid (CSF) with the serum values of these mediators in two different control groups, healthy subjects and HIV-infected untreated patients. Serum and CSF values of TNF-alpha, IL-10 and NO were higher in MS patients than in the serum of healthy controls. Two MS patients showed increased levels of NO in CSF, with inversion of the NO(SERUM)/NO(CSF) quotient, which is clearly indicative of an intrathecal production of NO. No correlation among the values of both cytokines and NO, and the laboratory parameters analysed in MS patients (IgG index, presence of IgG oligoclonal bands and albumin quotient) was found. The high levels of TNF-alpha and IL-10 (both in serum and CSF) accompanying an MS attack suggest a simultaneous expression of Th1 and Th2 cytokines as opposed to sequential expression of Th1 followed by Th2 as described in the models of experimental autoimmune encephalomyelitis (EAE). Globally, our results support the inherent heterogeneity of the disease.     

Immune Parameters That Distinguish Multiple Sclerosis Patients from Patients with Other Neurological Disorders at Presentation

Background/AimMultiple sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system. Effector T helper cells, mainly Th1 and Th17, cytotoxic T-cells, B-cells, macrophages, microglia, and the cytokines they secrete, are implicated in the initiation and maintenance of a deregulated immune response to myelin antigens and the ensuing immune-mediated demyelination. In this study, we investigated whether signature cytokines exist in MS patients at presentation to gain an insight into the underlying immunopathogenic processes at the early stage of the disease.MethodsWe collected serum and cerebrospinal fluid (CSF) samples from 123 patients at presentation, eventually diagnosed with MS or non-inflammatory (NIND) or inflammatory neurological diseases (IND) or symptomatic controls (SC). The levels of cytokines IFN-γ, TNF-α, TGF-β1, IL-2, IL-4, IL-6, IL-10 and IL-17 were measured, and cytokine ratios, such as Th1/Th2, Th1/Th17, and Type-1/Type-2, were calculated. All parameters were tested for their correlations with the intrathecal IgG synthesis.ResultsCytokine levels in CSF were lower than in serum in all the patients, with the exception of IL-6. Serum or CSF cytokine levels of MS patients did not differ significantly from NIND or SC, with the exception of serum IFN-γ and TNF-α that were significantly higher in NIND. IND patients presented with the highest levels of all cytokines in serum and CSF, with the exception of serum IL-10 and CSF IL-17. MS patients had a significantly lower serum Th1/Th2 ratio compared to the NIND and IND groups, and significantly lower serum Type-1/Type-2, IFN-γ/IL-10 and CSF Th1/Th17 ratios compared to IND patients. MS patients had a significantly higher CSF IL-17/IL-10 ratio compared to IND patients. The IgG index was higher in MS patients compared to the control groups; the differences reached statistical significance between the MS and the NIND and SC groups. Reiber-Felgenhauer analysis of the QIgG and QAlb indices revealed higher intrathecal IgG synthesis in MS patients, and higher blood-CSF barrier dysfunction in IND patients. The IgG index correlated with CSF IL-4 in MS patients only.ConclusionsWe found no signature cytokines or profiles thereof in MS patients at presentation. Only IND patients presented with a clear Th1 cytokine polarization in serum and CSF. The parameters that distinguished MS patients from patients with other neurological disorders were IgG intrathecal synthesis, the IgG index and its correlation with CSF IL-4 levels.     

Characterization of the antibody response against NeuGcGM3 ganglioside elicited in non-small cell lung cancer patients immunized with an anti-idiotype antibody

1E10 mAb is an anti-Id murine mAb (Ab2 mAb) specific for an Ab1 mAb that reacts with NeuGc-containing gangliosides, sulfatides, and Ags expressed in some human tumors. In preclinical studies, this Ab2 Ab was able to mimic NeuGc-containing gangliosides only in animals lacking expression of these Ags in normal tissues. In this study, we report on the immune responses elicited in 20 non-small cell lung cancer patients treated with 1 mg of aluminum hydroxide-precipitated 1E10 mAb. In the hyperimmune sera from 16 of 20 patients, a strong specific Ab response of both IgM and IgG isotypes against NeuGcGM3 ganglioside was observed. Patient immune sera were able to induce complement-independent cell death of NeuGcGM3-expressing X63 murine myeloma target cells. Significant immunoreactivity to NeuGcGM3 was still detected after the complete abrogation of the reactivity against 1E10 mAb by the adsorption of patient sera with this Ab. We hypothesize that Id(-)Ag(+) Abs could reflect the activation of an autologous idiotypic cascade into the patients. Both Id(+)Ag(+) and Id(-)Ag(+) fractions were separated by affinity chromatography and characterized. Although IgG isotype Abs were found in both fractions, IgM isotype Abs were found only in the Id(-)Ag(+) fraction. Both Id(+)Ag(+) and Id(-)Ag(+) Abs were able to specifically recognize and induce cell death in NeuGcGM3-expressing X63 myeloma target cells. Patients that developed IgG and/or IgM Abs against NeuGcGM3 showed longer median survival times.     

Measles-virus-specific IgG in optic neuritis and in multiple sclerosis after optic neuritis.

Measles-virus-specific IgG was measured in the serum of 100 patients who had presented with optic neuritis (ON) during 1960-74. When reviewed 41 of them were found to have developed definite symptoms and signs of multiple sclerosis (MS), their serum containing significantly higher titres of the antibody than sera from either the rest of the patients or a group of normal healthy controls. In a few patients from whom cerebrospinal fluid (CSF) was obtained in the acute phase of ON, titres of measles IgG in the serum was higher in those in whom the antibody was detected in the CSF than the serum of patients without CSF antibody.     

Increased intrathecal high-avidity anti-tau antibodies in patients with multiple sclerosis

Background

Antibodies against tau protein indicate an interaction between the immune system and the neurocytoskeleton and therefore may reflect axonal injury in multiple sclerosis (MS).

Methodology/Principal Findings

The levels and avidities of anti-tau IgG antibodies were measured using ELISA in paired cerebrospinal fluid (CSF) and serum samples obtained from 49 MS patients and 47 controls. Anti-tau antibodies were significantly elevated intrathecally (p<0.0001) in the MS group. The CSF anti-tau antibody levels were lower in MS patients receiving therapy than those without treatment (p<0.05). The avidities of anti-tau antibodies were higher in the CSF than in the serum (MS group p<0.0001; controls p<0.005). Anti-tau avidities in the CSF were elevated in MS patients in comparison with controls (p<0.05), but not in serum.

Conclusions

MS patients have higher levels of intrathecal anti-tau antibodies. Anti-tau antibodies have different avidities in different compartments with the highest values in the CSF of MS patients.     

Single-cell repertoire analysis demonstrates that clonal expansion is a prominent feature of the B cell response in multiple sclerosis cerebrospinal fluid

Single-cell RT-PCR was used to sample CD19(+) B cell repertoires in cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) or viral meningitis. Analysis of amplified Ab H and L chain products served to identify the rearranged germline segment and J segment, and to determine the degree of homology for the H and L chain sequence of individual B cells. The B cell repertoire of viral meningitis CSF was predominantly polyclonal, whereas B cell clonal expansion was a prominent feature of the IgG repertoire in three of four MS patients. Two dominant clonal populations in one MS CSF accounted for approximately 70% of the IgG H chain V regions sequenced, while the corresponding IgM repertoires were more heterogeneous. One clonal B cell population revealed multiple L chain rearrangements, raising the possibility of a role for receptor editing in shaping the B cell response in some MS patients. The most immediate implications of identifying rearranged Ig sequences in MS B cells is the potential to accurately recreate recombinant Abs from these overrepresented H and L chains that can be used to discover the relevant Ag(s) in MS.     

Genetic and Infectious Profiles Influence Cerebrospinal Fluid IgG Abnormality in Japanese Multiple Sclerosis Patients

Background

Abnormal intrathecal synthesis of IgG, reflected by cerebrospinal fluid (CSF) oligoclonal IgG bands (OBs) and increased IgG index, is much less frequently observed in Japanese multiple sclerosis (MS) cohorts compared with Western cohorts. We aimed to clarify whether genetic and common infectious backgrounds influence CSF IgG abnormality in Japanese MS patients.

Methodology

We analyzed HLA-DRB1 alleles, and IgG antibodies against Chlamydia pneumoniae, Helicobacter pylori, Epstein-Barr virus nuclear antigen (EBNA), and varicella zoster virus (VZV) in 94 patients with MS and 367 unrelated healthy controls (HCs). We defined CSF IgG abnormality as the presence of CSF OBs and/or increased IgG index (>0.658).

Principal Findings

CSF IgG abnormality was found in 59 of 94 (62.8%) MS patients. CSF IgG abnormality-positive patients had a significantly higher frequency of brain MRI lesions meeting the Barkhof criteria compared with abnormality-negative patients. Compared with HCs, CSF IgG abnormality-positive MS patients showed a significantly higher frequency of DRB1*1501, whereas CSF IgG abnormality-negative patients had a significantly higher frequency of DRB1*0405. CSF IgG abnormality-positive MS patients had a significantly higher frequency of anti-C. pneumoniae IgG antibodies compared with CSF IgG abnormality-negative MS patients, although there was no difference in the frequency of anti-C. pneumoniae IgG antibodies between HCs and total MS patients. Compared with HCs, anti-H. pylori IgG antibodies were detected significantly less frequently in the total MS patients, especially in CSF IgG abnormality-negative MS patients. The frequencies of antibodies against EBNA and VZV did not differ significantly among the groups.

Conclusions

CSF IgG abnormality is associated with Western MS-like brain MRI features. DRB1*1501 and C. pneumoniae infection confer CSF IgG abnormality, while DRB1*0405 and H. pylori infection are positively and negatively associated with CSF IgG abnormality-negative MS, respectively, suggesting that genetic and environmental factors differentially contribute to MS susceptibility according to the CSF IgG abnormality status.     

Identification of a unique idiotype in cerebrospinal fluid and serum of a patient with multiple sclerosis

Anti-idiotypic antibodies were prepared in mouse ascites fluid against the CSF-IgG of a patient with multiple sclerosis. After adsorption with pooled human IgG, the ascites fluid antibodies precipitated 20% of labeled autologous CSF IgG. By using a competitive radioimmunoassay, less than one microgram of unlabeled CSF IgG produced 50% inhibition of binding autologous 125I-labeled CSF IgG, whereas 50 micrograms of normal HIgG was not inhibitory. The idiotype could be found in both serum and CSF IgG and persisted over a 5-year period. The absolute concentration of idiotype in the CSF varied somewhat but remained from 4 to 10 times greater than that of the serum. One of 14 heterologous MS CSF was found to contain small amounts of inhibitory protein; eight CSF from patients with other neurologic diseases did not contain the idiotype.     

Comparison of Antibodies Hydrolyzing Myelin Basic Protein from the Cerebrospinal Fluid and Serum of Patients with Multiple Sclerosis

It was found that antibodies (Abs) against myelin basic protein (MBP) are the major components of the antibody response in multiple sclerosis (MS) patients. We have recently shown that IgGs from sera of MS patients are active in the hydrolysis of MBP. However, in literature there are no available data concerning possible MBP-hydrolyzing Abs in cerebrospinal fluid (CSF) of MS patients. We have shown that the average content of IgGs in their sera is about 195-fold higher than that in their CSF. Here we have compared, for the first time, the average content of lambda- and kappa-IgGs as well as IgGs of four different subclasses (IgG1-IgG4) in CSF and sera of MS patients. The average relative content of lambda-IgGs and kappa –IgGs in the case of CSFs (8.0 and 92.0%) and sera (12.3 and 87.7%) are comparable, while IgG1, IgG2, IgG3, and IgG4: CSF - 40.4, 49.0, 8.2, and 2.5% of total IgGs, respectively and the sera - 53.6, 36.0, 5.6, and 4.8%, decreased in different order. Electrophoretically and immunologically homogeneous IgGs were obtained by sequential affinity chromatography of the CSF proteins on protein G-Sepharose and FPLC gel filtration. We present first evidence showing that IgGs from CSF efficiently hydrolyze MBP and that their average specific catalytic activity is unpredictably ∼54-fold higher than that of Abs from sera of the same MS patients. Some possible reasons of these findings are discussed. We suggest that anti-MBP abzymes of CSF may promote important neuropathologic mechanisms in this chronic inflammatory disorder and in MS pathogenesis development.     

Biomarkers of Inflammation and Axonal Degeneration/Damage in Patients with Newly Diagnosed Multiple Sclerosis: Contributions of the Soluble CD163 CSF/Serum Ratio to a Biomarker Panel

Background

Expression of soluble CD163 (sCD163), a macrophage/microglia biomarker, is increased in inflammatory conditions, and sCD163 levels in the cerebrospinal fluid (CSF) have recently been shown to be elevated in patients with multiple sclerosis (MS): the sCD163 CSF/serum ratio was elevated in patients with relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and clinically isolated syndrome (CIS) compared with symptomatic controls.

Objective

To investigate the contributions of the sCD163 CSF/serum ratio to a biomarker panel focusing on inflammation and axonal degeneration in newly diagnosed MS; thus optimising a diagnostic biomarker panel for MS.

Methods

After a full MS diagnostic work-up, including collection of paired samples of CSF and serum, 125 patients were included in this study. Patients were divided into groups based on their diagnosis, and patients with normal clinical and paraclinical findings were defined as symptomatic controls. Serum and CSF levels, ratios, and indices of sCD163, CXCL13, osteopontin, neopterin, and CSF levels of neurofilament light polypeptide were determined by enzyme-linked immunosorbent assays (ELISAs). For sCD163 the results constitute a post-hoc analysis of already published data.

Results

All tested biomarkers, notably the sCD163 ratio, the CXCL13 ratio, the NEO ratio, the CSF level of NfL, the IgG index, and the serum level of OPN, were significantly correlated to RRMS, PPMS, and/or CIS. The individual biomarkers in single tests had a lower performance than the IgG index, however, their combined receiver operating characteristic (ROC) curve demonstrated excellent diagnostic discriminatory power.

Conclusion

The biomarker panel showed distinct profiles for each patient group and could be a valuable tool for clinical differentiation of MS subgroups. The combined ROC analysis showed that sCD163 contributes positively as a diagnostic marker to a panel of established MS biomarkers. Patients with PPMS were demonstrated to have significantly elevated levels of both inflammatory and degenerative markers.     

Soluble interleukin-2 receptor and soluble CD8 molecules in cerebrospinal fluid and serum of patients with multiple sclerosis.

The purpose of this study was to analyse soluble interleukin-2 receptor (sIL-2R) and soluble CD8 (sCD8) molecules in the cerebrospinal fluid (CSF) and serum of 18 patients with definite multiple sclerosis (MS) and of 16 with noninflammatory neurologic diseases (NIND). All MS patients suffered from an exacerbation of the relapsing-remitting form of the disease within one month before examination. The mean serum levels of sIL-2R and sCD8 in the MS patients were not significantly different from those of NIND patients. Only one patient with MS had detectable sIL-2R in the CSF. CSF sCD8 was detectable in 10 of 18 MS patients and in 1 of 16 NIND patients. Our data indicate that the CSF and serum sIL-2R concentrations do not correlate with the disease activity. Conversely, increased levels of sCD8 only in the CSF of MS patients support the hypothesis of an intrathecal activation of CD8+ cells in MS. We think that CSF sCD8 can be a useful marker for the presence of activated T cells in the central nervous system.     

Comparison of DNA-Hydrolyzing Antibodies from the Cerebrospinal Fluid and Serum of Patients with Multiple Sclerosis

It was found that high-affinity anti-DNA antibodies were one of the major components of the intrathecal IgG response in multiple sclerosis (MS) patients [Williamson et al., PNAS, 2001]. Recently we have shown that IgGs from the sera of MS patients are active in the hydrolysis of DNA. Here we have shown, for the first time, that average concentration of total proteins (132-fold), total IgGs (194-fold) and anti-DNA antibodies (200-fold) in the sera is significantly higher than that in the cerebrospinal fluid (CSF) of fifteen MS patients. The relative activities of total protein from sera and CSFs varied remarkably from patient to patient. It was surprising that the specific DNase activity of the total protein of CSF reparations were 198-fold higher than the serum ones. Electrophoretically and immunologically homogeneous IgGs were obtained by sequential affinity chromatography of the CSF proteins on protein G-Sepharose and FPLC gel filtration. We present first evidence showing that IgGs from CSF not only bind but efficiently hydrolyze DNA and that average specific DNase activity of homogeneous antibodies from CSF is unpredictably ∼49-fold higher than that from the sera of the same MS patients. Some possible reasons of these findings are discussed. We suggest that DNase IgGs of CSF may promote important neuropathologic mechanisms in this chronic inflammatory disorder and MS pathogenesis development.     

Idiotype restriction in murine lupus; high frequency of three public idiotypes on serum IgG in nephritic NZB/NZW F1 mice

Antibodies to self-antigens are characteristic of several human and murine autoimmune diseases. Subsets of those autoantibodies cause organ damage in some instances, such as IgG antibodies to DNA in human and murine systemic lupus erythematosus (SLE). Our experiments in the NZB/NZW F1 (BW) female mouse model of SLE were designed to define idiotypic (Id) structures on antibodies to DNA in attempts to distinguish pathogens from nonpathogens within the anti-DNA population. Two important findings emerged. First, the number of public Id expressed became relatively restricted as the mice aged, with three such Id (IdX, IdGN1 and IdGN2) dominating and accounting for 30 to 95% of the total serum IgG in all individual nephritic mice studied, and 81 to 86% of the total IgG in serum pools from 30-wk-old nephritic mice. Second, IdGN1 and IdGN2 constituted approximately 50% of the IgG deposited in glomeruli of nephritic mice; IdX was present in negligible quantities in glomeruli, whereas it was usually the most frequent Id in BW serum. These latter findings suggested that pathogens and nonpathogens can be distinguished by their idiotypy in this animal model. The finding of relative Id restriction suggests the occurrence of an idiotypic "spreading" phenomenon, in which a regulatory process appears as BW mice age that results in repeated selection and expansion of this small number of Id, one group of which, the IdGN, is pathogenic. This process was further suggested in experiments in which IdX was suppressed by administration of anti-IdX; the "escape" antibodies to DNA appearing after suppression of IdX were composed largely of IdGN1 and IdGN2, without a major contribution from Id-negative mutants. Defining the basis of this Id spreading or restriction phenomenon may provide important information regarding the pathogenesis of this autoimmune disease.     

Estimation of levels of IgG to multiple sclerosis specific brain antigens in the cerebrospinal fluid of MS patients

The binding of partially purified multiple sclerosis (MS) specific brain antigens (MSG2) and of the corresponding antigens of non-MS brains (KG2) to cerebrospinal fluid IgG of patients with MS and other neurological diseases was assayed employing sandwich enzyme linked immunosorbent assay (ELISA). Assay of the antigen-antibody binding revealed that the concentration of MSG2 required for the optimum binding to IgG in the undiluted MS CSFs was lower than that of KG2 in all cases. The index for IgG binding capacity of an antigen (IgBC) was expressed as a ratio of the optical density of the enzymic products in ELISA at the optimal antigen-antibody binding to the lowest concentration of the antigen required for the optimal binding. The IgBC of MSG2 was found to be linearly correlated with the IgG concentration in the CSF of MS patients. These results indicate that IgG with specificity to MSG2 may be present in the CSF of MS patients.     

Comparative analysis of the CD19+ and CD138+ cell antibody repertoires in the cerebrospinal fluid of patients with multiple sclerosis

Increased amounts of intrathecally synthesized IgG and oligoclonal bands have long been recognized as a hallmark of multiple sclerosis (MS). B cells and plasma cells are components of the inflammatory infiltrates in both active and chronic MS lesions, and increased numbers of these cells are present in MS cerebrospinal fluid (CSF). Single-cell RT-PCR was used to analyze both the CD19+ B cell and CD138+ plasma cell populations in CSF of two patients with clinically definite MS and of one MS patient whose CSF was obtained after a clinically isolated syndrome, but before the second episode. Sequence analysis of amplified IgG V region sequences identified the rearranged germline segments, extent of somatic mutation, and clonal relationships within and between the two cell populations in the three MS patients. Expanded B cell and plasma cell clones were detected in each MS CSF and in all three patients the CD138+ IgG repertoire was more restricted. However, little if any significant sequence overlap was observed between the CD19+ and CD138+ repertoires of each donor. Detection of plasma cell clones by single-cell PCR will facilitate the in vitro production of recombinant Abs useful in identifying disease-relevant Ags.     

Antibody‐based profiling of cerebrospinal fluid within multiple sclerosis

Antibody suspension bead arrays have proven to enable multiplexed and high‐throughput protein profiling in unfractionated plasma and serum samples through a direct labeling approach. We here describe the development and application of an assay for protein profiling of cerebrospinal fluid (CSF). While setting up the assay, systematic intensity differences between sample groups were observed that reflected inherent sample specific total protein amounts. Supplementing the labeling reaction with BSA and IgG diminished these differences without impairing the apparent sensitivity of the assay. We also assessed the effects of heat treatment on the analysis of CSF proteins and applied the assay to profile 43 selected proteins by 101 antibodies in 339 CSF samples from a multiple sclerosis (MS) cohort. Two proteins, GAP43 and SERPINA3 were found to have a discriminating potential with altered intensity levels between sample groups. GAP43 was detected at significantly lower levels in secondary progressive MS compared to early stages of MS and the control group of other neurological diseases. SERPINA3 instead was detected at higher levels in all MS patients compared to controls. The developed assay procedure now offers new possibilities for broad‐scale protein profiling of CSF within neurological disorders.     

Analysis of paraprotein transport into the saliva by using anti-idiotype antibodies

To determine the extent of clonal involvement of the secretory immune system and the origin of salivary immunoglobulins (Ig) in monoclonal gammopathy patients, saliva and serum samples were collected from five affected individuals (two IgA myelomas, one IgG myeloma, one IgG benign monoclonal gammopathy, and one IgM lymphoma) and were assayed for the presence of monoclonal Ig. Purified polyclonal or monoclonal anti-idiotype (Id) antibodies were prepared against each of the isolated serum paraproteins. In all five individuals, the patient saliva samples inhibited the binding of 125I-labeled homologous Ig to the corresponding anti-Id antibodies, but normal saliva did not. The concentration of Id in patients' saliva varied from 1 to 400 micrograms/ml; i.e., 0.004 to 1.0% of the corresponding serum values. Saliva of a lymphoma patient whose IgM kappa protein exhibited rheumatoid factor (RF) activity also contained RF. The salivary Id-bearing molecules were found to have the same Ig isotype as the serum paraproteins. The myeloma IgA represented a minor component (0.4 and 3.9%) of the total salivary IgA. The salivary IgA myeloma proteins were associated at least in part with secretory component, but the salivary IgG paraproteins were not. In an IgA myeloma patient, a minority (17%) of the IgA+ plasma cells found in the lacrymal gland biopsy specimen were Id+, whereas the great majority (98%) of bone marrow IgA plasma cells were Id+. The results suggest active transport rather than passive transudation of myeloma IgA into the patients' saliva, and the integrity of the secretory immune system was not compromised by the neoplastic process.     

Reactivation of human herpesvirus-6 in natalizumab treated multiple sclerosis patients

The alpha(4) integrin antagonist natalizumab was shown to be effective in patients with immune-mediated disorders but was unexpectedly associated with JC polyomavirus associated progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) and one Crohn's disease patients. Impaired immune surveillance due to natalizumab treatment may have contributed to the JCV reactivation. As HHV-6 has been suggested to play a role in MS, we asked whether this virus could also have been reactivated during natalizumab therapy. Matched sera and CSF from a limited set of MS patients treated with and without natalizumab were examined for evidence of HHV-6. In addition, we also superinfected a persistent JC virus infected glial cell with HHV-6A to determine if JC virus can be increased. Elevated serum HHV6 IgG and HHV-6A DNA was detected in the CSF of a subset of patients but not controls. We confirmed that superinfection with HHV-6 of a JC virus infected glial cells increased expression of JCV. These results support the hypothesis that treatment with natalizumab may be associated with reduced immune surveillance resulting in reactivation of viruses associated with MS pathogenesis.     

VH4 gene segments dominate the intrathecal humoral immune response in multiple sclerosis

A characteristic feature of the CNS inflammatory response in multiple sclerosis (MS) is the intrathecal synthesis of IgG and the presence of oligoclonal bands. A strong correlation between CD138(+) plasma blast numbers in MS cerebrospinal fluid (CeSF) and intrathecal IgG synthesis suggests that these cells are the major Ab-secreting cell type in MS CeSF. Sequencing of V regions from CD138(+) cells in MS CeSF has revealed somatically mutated and expanded IgG clonotypes consistent with an Ag-targeted response. In the present study, single-cell RT-PCR analysis of CD138(+) cells from 11 MS patients representing differing clinical courses and stages of disease identified expansion of CD138(+) cells with functionally rearranged V(H)4 gene segments as an overriding feature of MS CeSF repertoires. V(H)4 dominance was attributed to the preferential selection of specific V(H)4 genes, particularly gene segment V(H)4-39, which displayed a significant enrichment in CeSF compared with MS peripheral blood B cells. A modest increase in V(H)4 prevalence among MS peripheral blood IgG memory cells was also noted, suggesting that factors shaping the CD138 repertoire in CeSF might also influence the peripheral IgG memory cell pool. These results indicate a highly restricted B cell response in MS. Identifying the targets of CeSF plasma cells may yield insights into disease pathogenesis.