Intrathecal Immunoglobulin Production Research Articles

B lineage cells in the inflammatory central nervous system environment: Migration, maintenance, local antibody production, and therapeutic modulation

B cells have long played an enigmatic role in the scenario of multiple sclerosis pathogenesis. This review summarizes recent progress in our understanding of B-cell trafficking, survival, and differentiation in the central nervous system (CNS). We propose four possible routes of intrathecal immunoglobulin-producing cells. The inflammatory CNS provides a unique, B-cell-friendly environment, in which B lineage cells, notably long-lived plasma cells, can survive for many years, perhaps even for a lifetime. These new findings offer a plausible explanation for the notorious persistence and stability of cerebrospinal fluid oligoclonal bands. Furthermore, we highlight similarities and differences of intrathecal immunoglobulin production in multiple sclerosis patients and patients with other CNS inflammatory conditions. Finally, we outline the possibly double-edged effects of B cells and immunoglobulin in the CNS and discuss various therapeutic strategies for targeting the B-cell response.

Chemokines in multiple sclerosis: CXCL12 and CXCL13 up-regulation is differentially linked to CNS immune cell recruitment

Understanding the mechanisms of immune cell migration to multiple sclerosis lesions offers significant therapeutic potential. This study focused on the chemokines CXCL12 (SDF-1) and CXCL13 (BCA-1), both of which regulate B cell migration in lymphoid tissues. We report that immunohistologically CXCL12 was constitutively expressed in CNS parenchyma on blood vessel walls. In both active and chronic inactive multiple sclerosis lesions CXCL12 protein was elevated and detected on astrocytes and blood vessels. Quantitative PCR demonstrated that CXCL13 was produced in actively demyelinating multiple sclerosis lesions, but not in chronic inactive lesions or in the CNS of subjects who had no neurological disease. CXCL13 protein was localized in perivascular infiltrates and scattered infiltrating cells in lesion parenchyma. In the CSF of relapsing-remitting multiple sclerosis patients, both CXCL12 and CXCL13 were elevated. CXCL13, but not CXCL12, levels correlated strongly with intrathecal immunoglobulin production as well as the presence of B cells, plasma blasts and T cells. About 20% of CSF CD4+ cells and almost all B cells expressed the CXCL13 receptor CXCR5. In vitro, CXCL13 was produced by monocytes and at much higher levels by macrophages. CXCL13 mRNA and protein expression was induced by TNFalpha and IL-1beta but inhibited by IL-4 and IFNgamma. Together, CXCL12 and CXCL13 are elevated in active multiple sclerosis lesions and CXCL12 also in inactive lesions. The consequences of CXCL12 up-regulation could be manifold. CXCL12 localization on blood vessels indicates a possible role in leucocyte extravasation, and CXCL12 may contribute to plasma cell persistence since its receptor CXCR4 is retained during plasma cell differentiation. CXCL12 may contribute to axonal damage as it can become a neurotoxic mediator of cleavage by metalloproteases, which are present in multiple sclerosis lesions. The strong linkage of CXCL13 to immune cells and immunoglobulin levels in CSF suggests that this is one of the factors that attract and maintain B and T cells in inflamed CNS lesions. Therefore, both CXCL13 and CXCR5 may be promising therapeutic targets in multiple sclerosis.

Effects of antiretroviral treatment on blood–brain barrier integrity and intrathecal immunoglobulin production in neuroasymptomatic HIV‐1‐infected patients

To study the effect of antiretroviral combination therapy on blood-brain barrier (BBB) integrity and intrathecal immunoglobulin G (IgG) production. Lumbar punctures were performed on 38 neurologically asymptomatic, treatment-naive HIV-1-infected patients prior to and during treatment at intervals of approximately 4 months, 1 year and 2 years. Albumin ratio and IgG index were analysed as markers of BBB integrity and intrathecal IgG synthesis. HIV-1 RNA decreased to < 50 HIV-1 RNA copies/mL in the cerebrospinal fluid (CSF) of all patients and in the plasma of all but one patient. Only 5% of patients had elevated albumin ratio values at baseline, while 56% had an elevated IgG index. There was no significant reduction of the albumin ratio or the IgG index. After 2 years of treatment all patients had normal albumin ratio values, while 41% still had increased IgG index levels. Up to 2 years after the initiation of treatment, the favourable impact of antiretroviral combination treatment on CSF viral load was not accompanied by a similar reduction of intrathecal IgG production. BBB function, measured as the albumin ratio, was not significantly changed in this cohort of neurologically asymptomatic HIV-1-infected patients.

Intrathecal antibody (IgG) production against human herpesvirus type 6 occurs in about 20% of multiple sclerosis patients and might be linked to a polyspecific B–cell response

Human herpesvirus 6 (HHV-6) is one of many infectious agents that have been implicated in the pathogenesis of multiple sclerosis (MS). Intrathecal immunoglobulin (Ig) production with oligoclonal CSF bands are hallmarks of both MS and infections of the CNS. In neuroinfections the intrathecal Ig production is directed largely against the respective agent, while MS patients mount an intrathecal Ig production against different pathogens. In this study a total of 77 serum/CSF pairs were first analyzed for an intrathecal immune response against HHV-6. We found that 21% of the MS patients, but none of the control donors showed an intrathecal immunoglobulin (Ig) response against HHV-6 (p = 0.017). Patients with such an intrathecal Ig production had a significantly higher total amount of Ig (p = 0.007) and a higher cell number in the CSF (p = 0.03). In a second step, four of the MS-patients who showed a strong intrathecal Ig production against HHV-6 were examined for immune reactivity against other viruses (human herpesvirus type 1, measles virus, human cytomegalovirus, rubella virus, varicella zoster virus). All of these patients had an intrathecal Ig production against at least one other, unrelated virus. Together, our findings strongly argue that in the majority of MS patients without an intrathecal Ig response to HHV-6 (about 80 % in our study), this virus is not involved in the pathogenesis. In the other 20% the intrathecal Ig production to HHV-6 might reflect reactivation of HHV-6 or could be part of a polyspecific B cell activation.

The diagnosis of primary progressive multiple sclerosis

Primary progressive multiple sclerosis (PPMS) is a rather unique form of the more common relapsing inflammatory demyelinative disease. The absence of attacks that typify relapsing forms of MS imposes special challenges for diagnosis, but also provides an opportunity to study the pathogenesis of the more progressive aspects of the disease process in isolation of confounding transient clinical events. In this review, recent advances in diagnostic approaches are considered in relationship to baseline data from a large multinational study designed to better characterize and treat this clinical phenotype. PPMS subjects with cerebral spinal fluid (CSF) findings consistent with intrathecal immunoglobulin production may have a more tissue destructive disease process than those whose CSF lacks evidence of a B-cell immunopathogenic disease component.

Multiple sclerosis. Chlamydia hypothesis in debate

Recently, an association between multiple sclerosis and Chlamydia pneumoniae infection has been suggested. Because standardized PCR protocols are lacking, a series of studies could not clarify whether C. pneumoniae is present in brain tissue and CSF of MS patients. Therefore, other studies focused on the humoral immune response against C. pneumoniae: 24% of MS patients, but only 5% of the control patients showed intrathecally produced antibodies against C. pneumoniae. If an infection with C. pneumoniae was involved in the pathogenesis of MS, one would expect that, in analogy to other infections of the CNS, the oligoclonal bands in the CSF of MS patients would recognize the responsible agent. However, the results we obtained by affinity-mediated immunoblots showed that the oligoclonal bands in the CSF of MS patients are not directed against Chlamydia antigen. In contrast to this, we found that the immunoglobulins in the CSF of neuroborreliosis patients reacted strongly against Borrelia antigen in the affinity-mediated immunoblots. In light of these results we assume that the intrathecal immunoglobulin production against C. pneumoniae is part of a polyspecific immune response. Thus, it is not likely that C. pneumoniae is causally linked to the pathogenesis of multiple sclerosis.

Intrathecal antibody production against Chlamydia pneumoniae in multiple sclerosis is part of a polyspecific immune response.

Chronic intrathecal immunoglobulin (Ig) production is a hallmark of multiple sclerosis characterized by the presence of oligoclonal IgGs and, in addition, polyspecific recognition of different pathogens such as measles, rubella and herpes zoster virus. While the antigen specificity of the oligoclonal IgGs in multiple sclerosis is largely unknown, the oligoclonal IgGs arising during CNS infectious diseases are reactive against the specific pathogen. Recently, a link between Chlamydia pneumoniae and multiple sclerosis has been claimed. To test the possible role of C. pneumoniae in multiple sclerosis, we analysed (i) whether there is intrathecal IgG production against C. pneumoniae in multiple sclerosis and (ii) if the oligoclonal IgGs in the CSF of multiple sclerosis patients recognize C. pneumoniae. By studying paired serum-CSF samples from 120 subjects (definite multiple sclerosis, 46; probable multiple sclerosis, 12; other inflammatory neurological diseases, 35; other neurological diseases, 27) by enzyme-linked immunosorbent assay, we found that 24% of all patients with definite multiple sclerosis, but only 5% of patients with other inflammatory or non-inflammatory diseases, produced IgGs specific for C. pneumoniae intrathecally (definite multiple sclerosis versus other inflammatory neurological diseases: P = 0.027). The presence of intrathecal IgGs to C. pneumoniae was independent of the duration of disease and relatively stable over time. The major CSF oligoclonal IgG bands from multiple sclerosis patients with an intrathecal Ig production to C. pneumoniae did not react towards purified elementary bodies and reticulate bodies of C. pneumoniae on affinity-mediated immunoblot following isoelectric focusing (IEF-western blots). In contrast, the IgGs in the CSF of control patients with neuroborreliosis strongly reacted with their specific pathogen, Borrelia burgdorferi, by IEF-western blot analysis. Concomitant analysis of the CSF of 23 patients with a nested polymerase chain reaction for C. pneumoniae was negative in all cases. Together, our findings strongly suggest that the immune response to C. pneumoniae is part of a polyspecific intrathecal Ig production, as is commonly observed with other pathogens. This argues against a specific role for C. pneumoniae in multiple sclerosis.

Significant correlation between IL-10 levels and IgG indices in the cerebrospinal fluid of patients with multiple sclerosis

We measured the interleukin (IL)-6 and IL-10 levels in the plasma and the cerebrospinal fluid (CSF) of a total of 23 relapsing multiple sclerosis (MS) patients [18 with conventional form of MS (C-MS) and 5 with optic-spinal form of MS (OS-MS)] using ELISA and correlated them with the IgG indices and oligoclonal IgG bands (OB) to determine whether these cytokines play a role in the intrathecal immunoglobulin production. IL-10 values in the CSF significantly correlated with the IgG indices and tended to be higher in OB-positive patients. In contrast, IL-10 values in the plasma and IL-6 values in the CSF and the plasma did not correlate with the IgG indices or OB. The CSF-IL-10 value in OS-MS were much lower than those of C-MS, but those of CSF IL-6 did not differ between C-MS and OS-MS. The results remained unchanged even when OS-MS patients were excluded. Our results may suggest a role of IL-10 in upregulating the intrathecal IgG synthesis in relapsing MS.

Elevated Cerebrospinal Fluid Sulfatide Concentrations as a Sign of Increased Metabolic Turnover of Myelin in HIV Type I Infection

Cerebrospinal fluid (CSF) sulfatide concentrations were analyzed in 18 patients with asymptomatic HIV-1 infection, in 16 patients with AIDS who were free from opportunistic infections in the central nervous system (CNS), in 12 HIV-1-infected patients with opportunistic CNS infections or lymphoma, and in 19 HIV-negative controls, by thin-layer chromatography overlay technique using an antisulfatide antibody to estimate the metabolic turnover of myelin. The majority of asymptomatic HIV-1-infected patients had normal CSF sulfatide concentrations, but the mean CSF sulfatide concentration was still elevated compared to that in HIV-negative controls (152 compared to 99 nmol/liter, p < 0.05). The CSF sulfatide concentrations in the AIDS group (mean 395 nmol/liter) were significantly increased compared to those in asymptomatic HIV-1-infected patients (p < 0.01) and in HIV-negative controls (p < 0.001), but did not differ significantly between patients with and without dementia. Increased CSF sulfatide concentrations were also found in patients with opportunistic infection or lymphoma in the CNS. In the entire study population, the sulfatide levels were associated with blood-brain barrier function, but not with intrathecal immunoglobulin production or with positive HIV isolations from CSF. Thus, signs of white matter changes, measured as increased CSF sulfatide concentrations, could be found in some asymptomatic HIV-1-infected patients, but the highest levels were seen in patients with AIDS.

Increased interleukin-6 mRNA expression in blood and cerebrospinal fluid mononuclear cells in multiple sclerosis

The increased intrathecal production of immunoglobulins within the cerebrospinal fluid (CSF) compartment commonly observed in multiple sclerosis (MS) implicates participation of B cell activating factors. One effect of the cytokine interleukin (IL) -6 is induction of immunoglobulin production by activated B cells. Employing in situ hybridization (ISH) with synthetic oligonucleotide probes, we measured numbers of IL-6 mRNA-expressing mononuclear cells (MNC) in blood and CSF from patients with MS, aseptic meningo-encephalitis (AM), and in blood from patients with other neurological diseases (OND) and healthy subjects. Numbers of IL-6 mRNA-expressing MNC were elevated in blood (mean frequency 1 per 33000 MNC) and even further enriched in the CSF (1 per 10000 MNC) of MS patients, and to a similar extent in AM patients' blood. Cultivation in the presence of myelin basic protein and proteolipid protein revealed strong augmentation of IL-6 mRNA-positive cells in MS but not in OND. The results suggest that IL-6 is one of several cytokines which are upregulated in MS, in particular locally in the CSF. A role of IL-6 in MS, whether disease-promoting or protective, remains unclear.

Fc Receptors for IgG on Cultured Human Microglia Mediate Cytotoxicity and Phagocytosis of Antibody-coated Targets

We have utilized surgically resected human central nervous system (CNS) tissue to determine the expression and functions of Fc receptors (Fc gamma R) on individual cell types found within the CNS. We observed all three classes of Fc gamma R on microglial cells in situ and in vitro, but not on astrocytes or oligodendrocytes. Incubation of cultured microglia with immune complexes (antibody-coated red blood cells) induced phagocytosis, antibody-dependent cell-mediated cytotoxicity (ADCC), and oxidative bursts. We also found that microglia have the capability to produce T cell stimulatory soluble mediators after Fc gamma R crosslinking. These functional responses were enhanced by pretreatment of the microglia with interferon-gamma (IFN-gamma). Our results implicate microglial effector responses triggered by interaction of Fc gamma R with opsonized antigens as potential mediators of tissue injury within the CNS. Such injury may be particularly applicable to multiple sclerosis, an inflammatory demyelinating disease characterized by intrathecal production of immunoglobulins and cytokines.

Astasia-abasia revealing a primary Sjögren's syndrome

A 63-year-old woman presented with mild arthralgias and inability to stand and walk without other significant neuropsychiatric abnormality. Neurological explorations showed intrathecal oligoclonal immunoglobulin production in CSF and numerous bright foci at brain MRI. A primary Sjögren's syndrome was concomitantly evidenced and was thought to be the cause of the astasia-abasia symptom by multiple brain involvement. Patient's condition gradually improved with hydroxychloroquine and corticosteroid therapy. Central nervous system involvement by primary Sjögren's syndrome is discussed.

Borrelia burgdorferi-specific intrathecal antibody production in neuroborreliosis: a follow-up study.

We used a capture ELISA with biotinylated Borrelia burgdorferi flagella as antigen to analyze the kinetics of intrathecal antibody production against B burgdorferi in 27 patients with neuroborreliosis. All patients had lymphocytic pleocytosis, 13/27 had intrathecal specific IgM production, and 26/27 had intrathecal IgG synthesis against B burgdorferi before therapy. All patients improved after antibiotic treatment. At follow-up, 11 months to 8 years later (median, 1 1/2 years), 20 patients had had a complete clinical recovery, and seven suffered from sequelae. One patient without sequelae had persistent specific intrathecal IgM synthesis. Ten of 20 patients without sequelae and five of seven patients with sequelae had persistent intrathecal IgG production against B burgdorferi. None of the 16 patients with persistent specific intrathecal antibody synthesis had pleocytosis at follow-up. Therefore, intrathecal immunoglobulin production against B burgdorferi, especially IgG, may persist for years after treatment of neuroborreliosis without clinical signs of active disease.

Specific antigen binding by activated cerebrospinal fluid B lymphocytes in acute neuroborreliosis.

A recently developed immunocytochemical antigen-binding sandwich test for the identification of specific activated B lymphocytes was applied to cerebrospinal fluid cells and peripheral blood mononuclear cells in patients with acute neuroborreliosis. Discrimination of antigen-binding phagocytes was achieved by double staining with monoclonal antibodies. Specific activated B lymphocytes were much more numerous in cerebrospinal fluid than in blood, showing great interindividual differences. When intrathecal immunoglobulin production was present, the number of specific activated B lymphocytes was also high. The specificity of all activated B lymphocytes ranged from 10% to 60% and was higher in the acute stage than after treatment.

Significance of CSF immunoglobulins in monitoring neurologic disease activity in Behçet's disease

We examined the intrathecal production of immunoglobulins (Ig) G, A, and M in 16 patients with Behçet's disease, 13 of whom have CNS involvement, and in 40 neurologic controls. Oligoclonal IgA and IgM bands were mainly detected in CSF samples from patients with active neuro-Behçet's disease and were documented to disappear when neurologic manifestations remit. Oligoclonal IgG bands, however, were not related to disease activity and were also found in some neurologic controls. High immunoglobulin index values were detected in both active and quiescent diseases and were high in some patients with impaired blood-CSF barriers. The study presented here demonstrates that CSF oligoclonal IgA and IgM may be helpful in monitoring CNS disease activity in neuro-Behçet's and could be useful in understanding the pathogenesis of this disease.

Induction and regulation of interleukin-6 gene expression in rat astrocytes

Cells that produce interleukin-6 (IL-6) require the presence of signaling molecules since this cytokine is not normally constitutively expressed. It is now established that astrocytes produce IL-6; however, the precise inducing molecules and the kinetics of their action have not yet been clearly identified. In the current study, we show that either interleukin-1β (IL-1β) or tumor necrosis factor-α (TNF-α) exert a strong inducing signal for IL-6 in primary rat astrocytes. When the two cytokines are added together the response is synergistic, suggesting that each cytokine may induce IL-6 gene expression by different pathways. Interferon-γ (IFN-γ) does not affect IL-6 expression although if it is added in conjunction with IL-1β, an augmented induction of IL-6 occurs. In addition to the cytokines, bacterial lipopolysaccharide (LPS) and the calcium ionophore, A23187, induce IL-6 expression. IL-6 expression can be blocked by the glucocorticoid analogue, dexamethasone. IL-6 induction by LPS/Ca 2+ ionophore is more sensitive to the suppressive effects of dexamethasone than is IL-6 induction by TNF-α/IL-1β. Cycloheximide (CHX), an inhibitor of protein synthesis, markedly increased levels of IL-6 mRNA in both unstimulated and stimulated astrocytes, indicating that ongoing protein synthesis is not required for astrocyte IL-6 gene expression. We propose that astrocyte-produced IL-6 may have a role in augmenting intracerebral immune responses in neurological diseases such as multiple sclerosis (MS), AIDS dementia complex (ADC), and viral infections. These diseases are characterized by infiltration of lymphoid and mononuclear cells into the central nervous system (CNS), and intrathecal production of immunoglobulins. IL-6 may act to promote terminal differentiation of B cells in the CNS, leading to immunoglobulin synthesis.

Unusual manifestations of Epstein-Barr Virus encephalomyelitis

A patient with atypical manifestations of Epstein-Barr Virus (EBV) encephalomyelitis is presented. The patient had unusual spinal fluid immunoglobulin abnormalities, the syndrome of inappropriate anti-diuretic hormone secretion, autonomic dysfunction and spinal arachnoiditis. The cisternal CSF, with a very high IgG level (34.3 mg/dl; normal less than 6.1) but a normal albumin content, displayed evidence of massive intrathecal immunoglobulin production. This was further confirmed by the presence of oligoclonal bands. These clinical manifestations have not previously been reported in encephalomyelitis associated with EBV infection.

Cerebrospinal fluid immunoglobulin abnormalities in neurosarcoidosis.

A retrospective chart review of neurosarcoidosis at the University of Texas Medical Branch (Galveston) between 1982 and 1987 revealed 99 patients with sarcoidosis. Six patients were diagnosed with neurosarcoidosis and had electrophoresis of serum and cerebrospinal fluid performed (one patient with a ventriculoperitoneal shunt was later excluded). Cerebrospinal fluid immunoglobulins and albumin levels were determined followed by calculation of an IgG index and synthesis rate for each patient. Four (80%) of five patients had elevated IgG indexes and synthesis rates indicative of intrathecal immunoglobulin production. No patient had immunoglobulin oligoclonal bands detected. To date, results of electrophoresis of cerebrospinal fluid in neurosarcoidosis have been reported in 37 patients among four series. Of these, only nine patients (24%) have had either an elevated IgG index or synthesis rate. Our series suggests that intrathecal immunoglobulin production in neurosarcoidosis occurs more frequently than previously described. Furthermore, the elevated indexes and synthesis rates without associated oligoclonal bands suggests a polyclonal immunoglobulin response.

Magnetic resonance imaging, evoked responses and cerebrospinal fluid findings in a follow-up study of children with optic neuritis.

Fourteen patients with previous optic neuritis (ON) in childhood were examined by magnetic resonance (MR) imaging from two months to 14 years after the onset of symptoms. Five patients had a single monosymptomatic course of ON but 7 developed multiple sclerosis (MS); 2 had another demyelinating disease. Eight patients had high signal intensity areas in the T2 weighted images compatible with MS plaques in MR scan; 2 with monosymptomatic ON, 5 with MS and one with another demyelinating disease. The plaques were periventricular or in the optic radiation. The plaques could already be seen during the first symptoms of ON. All 7 MS patients had abnormal visual evoked response, 3/4 abnormal somatosensory evoked response and 5/6 intrathecal immunoglobulin production, when examined at onset of optic neuritis or at follow-up. All patients except one, with lesions in MR, had either oligoclonal CSF antibodies or Dr2 HLA antigen. We suggest that MR is a very sensitive test showing MR abnormalities in children with ON. It is an important tool in the early assessment of MS.

Cytological and immunoglobulin findings in cerebrospinal fluid of symptomatic and asymptomatic human immunodeficiency virus (HIV) seropositive patients.

Immunostimulation in the central nervous system (CNS) measured as abnormal intrathecal immunoglobulin production or activated lymphocytes in the cerebrospinal fluid (CSF), was found in 22 of 25 HIV seropositive patients. All of 11 patients with symptomatic HIV infection and nine of 14 asymptomatic patients had an increased IgG index or a Tourtellotte's production number indicating CNS infection. The amount of intrathecal immunoglobulin was not correlated to the severity of disease since five of six AIDS patients had only slightly elevated values, while some patients without AIDS had a high intrathecal immunoglobulin production. Activated lymphocytes and plasma cells in CSF were frequently found in symptomatic HIV patients without AIDS as well as in asymptomatic HIV seropositive patients. Macrophages and activated monocytes were observed in CSF from AIDS patients. The results indicate that HIV has a high neurotropicity and is spread to CNS in all stages of the infection.