Cryptococcus neoformans-specific oligoclonal immunoglobulins in cerebrospinal fluid in cryptococcal meningitis

Coronaviruses and their relationship with multiple sclerosis: is the prevalence of multiple sclerosis going to increase after the Covid-19 pandemia?

The purpose of this review is to examine whether there is a possible (etiological/triggering) relationship between infection with various Coronaviruses, including Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), the virus responsible for the Coronavirus disease-19 (Covid-19) pandemia, and Multiple Sclerosis (MS), and whether an increase of the prevalence of MS after the current Covid-19 pandemia should be expected, examining new and preexisting data. Although the exact pathogenesis of MS remains unknown, environmental agents seem to greatly influence the onset of the disease, with viruses being the most popular candidate. Existing data support this possible etiological relationship between viruses and MS, and experimental studies show that Coronaviruses can actually induce an MS-like demyelinating disease in animal models. Findings in MS patients could also be compatible with this coronaviral MS hypothesis. More importantly, current data from the Covid-19 pandemia show that SARS-CoV-2 can trigger autoimmunity and possibly induce autoimmune diseases, in the Central Nervous System as well, strengthening the viral hypothesis of MS. If we accept that Coronaviruses can induce MS, it is reasonable to expect an increase in the prevalence of MS after the Covid-19 pandemia. This knowledge is of great importance in order to protect the aging groups that are more vulnerable against autoimmune diseases and MS specifically, and to establish proper vaccination and health policies.

Hypothesis: Multiple sclerosis is caused by three-hits, strictly in order, in genetically susceptible persons

Multiple Sclerosis is a chronic, progressive and debilitating neurological disease which, despite extensive study for over 100 years, remains of enigmatic aetiology. Drawn from the epidemiological evidence, there exists a consensus that there are environmental (possibly infectious) factors that contribute to disease pathogenesis that have not yet been fully elucidated. Here we propose a three-tiered hypothesis: 1) a clinic-epidemiological model of multiple sclerosis as a rare late complication of two sequential infections (with the temporal sequence of infections being important); 2) a proposal that the first event is helminthic infection with Enterobius Vermicularis, and the second is Epstein Barr Virus infection; and 3) a proposal for a testable biological mechanism, involving T-Cell exhaustion for Epstein-Barr Virus protein LMP2A. We believe that this model satisfies some of the as-yet unexplained features of multiple sclerosis epidemiology, is consistent with the clinical and neuropathological features of the disease and is potentially testable by experiment. This model may be generalizable to other autoimmune diseases.

A Neuroprimer: Principles of Central Nervous System Immunity

Despite longstanding perceptions, robust innate and adaptive immune responses occur within the central nervous system (CNS) in response to infection and tissue damage. Although necessary to control infection, immune responses can lead to severe CNS pathology in the context of both viral infection and autoimmunity. Research into how the central nervous and immune systems communicate has accelerated over the past 20 years leading to a better understanding of pathways controlling immune activation and neuroinflammation that have guided the approval of new disease-modifying therapies to treat CNS immunopathology, particularly the inflammatory demyelinating disease multiple sclerosis. This article provides an introduction into the basic principles underlying immune responses within the CNS that developed from experimental animal models of both neurotropic virus infection and autoimmune T cell-mediated CNS demyelination.

Cerebrospinal Fluid in a Small Cohort of Patients with Multiple Sclerosis Was Generally Free of Microbial DNA

Multiple sclerosis (MS) is a common cause of non-traumatic neurologic disability with high incidence in many developed countries. Although the etiology of the disease remains elusive, it is thought to entail genetic and environmental causes, and microbial pathogens have also been envisioned as contributors to the phenotype. We conducted a metagenomic survey in cerebrospinal fluid (CSF) from 28 MS patients and 15 patients suffering other type of neurological conditions. We detected bacterial reads in eight out of the 15 non-MS patients and in a single MS patient, at an abundance >1% of total classified reads. Two patients were of special interest: one non-MS patient harbored ~73% bacterial reads, while an MS patient had ~83% bacterial reads. In the former case, Veillonella parvula, a bacterium occasionally found associated with meningitis was the predominant species, whilst Kocuria flava, apparently an environmental bacterium, predominated in the latter case. Thirty-four out of 43 samples contained <1% bacterial reads, which we regard as cross- or environmental contamination. A few viral reads corresponding to Epstein-Barr virus, cytomegalovirus, and parvovirus were also identified. Our results suggest that CSF of MS patients is often (but not always) free of microbial DNA.

Viruses and multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disorder of unknown etiology, possibly caused by a virus or virus-triggered immunopathology. The virus might reactivate after years of latency and lyse oligodendrocytes, as in progressive multifocal leukoencephalopathy, or initiate immunopathological demyelination, as in animals infected with Theiler's murine encephalomyelitis virus or coronaviruses. The argument for a viral cause of MS is supported by epidemiological analyses and studies of MS in identical twins, indicating that disease is acquired. However, the most important evidence is the presence of bands of oligoclonal IgG (OCBs) in MS brain and CSF that persist throughout the lifetime of the patient. OCBs are found almost exclusively in infectious CNS disorders, and antigenic targets of OCBs represent the agent that causes disease. Here, the authors review past attempts to identify an infectious agent in MS brain cells and discuss the promise of using recombinant antibodies generated from clonally expanded plasma cells in brain and CSF to identify disease-relevant antigens. They show how this strategy has been used successfully to analyze antigen specificity in subacute sclerosing panencephalitis, a chronic encephalitis caused by measles virus, and in neuromyelitis optica, a chronic autoimmune demyelinating disease produced by antibodies directed against the aquaporin-4 water channel.

A mechanism of virus-induced demyelination

Myelin forms an insulating sheath surrounding axons in the central and peripheral nervous systems and is essential for rapid propagation of neuronal action potentials. Demyelination is an acquired disorder in which normally formed myelin degenerates, exposing axons to the extracellular environment. The result is dysfunction of normal neuron-to-neuron communication and in many cases, varying degrees of axonal degeneration. Numerous central nervous system demyelinating disorders exist, including multiple sclerosis. Although demyelination is the major manifestation of most of the demyelinating diseases, recent studies have clearly documented concomitant axonal loss to varying degrees resulting in long-term disability. Axonal injury may occur secondary to myelin damage (outside-in model) or myelin damage may occur secondary to axonal injury (inside-out model). Viral induced demyelination models, has provided unique imminent into the cellular mechanisms of myelin destruction. They illustrate mechanisms of viral persistence, including latent infections, virus reactivation and viral-induced tissue damage. These studies have also provided excellent paradigms to study the interactions between the immune system and the central nervous system (CNS). In this review we will discuss potential cellular and molecular mechanism of central nervous system axonal loss and demyelination in a viral induced mouse model of multiple sclerosis.

Recombinant antibodies generated from both clonal and less abundant plasma cell immunoglobulin G sequences in subacute sclerosing panencephalitis brain are directed against measles virus

Increased immunoglobulin G (IgG) and intrathecally produced oligoclonal bands (OGBs) are characteristic of a limited number of inflammatory central nervous system (CNS) diseases and are often directed against the cause of disease. In subacute sclerosing panencephalitis (SSPE), the cause of disease and the target of the oligoclonal response is measles virus (MV). The authors previously showed that clonally expanded populations of CD38+ plasma cells in SSPE brain, the likely source of OGBs, are directed against MV. In characterizing the breadth of the plasma cell reactivities, the authors found that a large proportion of the less abundant plasma cells are also directed against MV. The intrathecal response may be useful in determining the causes of other inflammatory CNS diseases, such as multiple sclerosis, Behcet's disease, and neurosarcoidosis.

The B cell response in multiple sclerosis

Multiple sclerosis (MS) plaques and CSF contain increased amounts of intrathecally synthesized IgG, manifest as oligoclonal bands (OCBs) after protein electrophoresis. OCBs are not unique to MS and are also produced in infectious diseases of the CNS, in which the oligoclonal IgG has been shown to be antibody directed against the disease-causing agent. Thus, analysis of antibody specificity may identify the causative agent/antigen in MS. This review discusses recent studies that have analyzed the phenotypes of B cells in MS which infiltrate the CNS and the molecular features of their antigen-binding regions. Together with histologic studies showing the presence of ectopic lymphoid follicles in the meninges of some MS patients, this data supports the notion of a targeted and compartmentalized humoral response in MS.

A possible link between multiple sclerosis and Creutzfeldt-Jakob disease based on clinical, genetic, pathological and immunological evidence involving Acinetobacter bacteria

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the nervous system. There is an increasingly likelihood that MS could be triggered/perpetuated by environmental (microbial) agents. Sporadic Creutzfeldt-Jakob disease (sCJD) is a relatively rare but fatal disease, which shows various clinical, genetic, pathological and immunological features through which it resembles a severe form of MS. The disease in some patients with MS may show a rapidly downhill course with death occurring within one to two years and a similar situation occurs in sCJD. The occurrence of these comparative similarities between MS and sCJD could be explained on the basis that both of these conditions might be sharing a common aetiopathogenic factor such as infection by Acinetobacter microbes and this possibility could be investigated further by carrying out immunological studies on a relatively large numbers of patients with MS and CJD.

Laser-capture microdissection of plasma cells from subacute sclerosing panencephalitis brain reveals intrathecal disease-relevant antibodies

Increased IgG and oligoclonal bands are found in cerebrospinal fluid of humans with chronic infectious CNS disease. Studies have shown that these oligoclonal bands are antibodies directed against the agent that causes disease. Laser-capture microdissection was used to isolate individual CD38+ plasma cells from the brain of a patient with subacute sclerosing panencephalitis, and single-cell RT-PCR was used to analyze individual IgG heavy and light chains expressed by each cell. Based on overrepresented IgG sequences, we constructed functional recombinant antibodies (recombinant IgGs) and determined their specificities. Five of eight recombinant IgGs recognized measles virus, the cause of subacute sclerosing panencephalitis. These results demonstrate that overrepresented IgG sequences in postmortem brains can be used to produce functional recombinant antibodies that recognize their target antigens. This strategy can be used to identify disease-relevant antigens in CNS inflammatory diseases of unknown etiology.

Infectious causes of multiple sclerosis

Multiple sclerosis (MS) is a serious chronic neurological disorder in which demyelination and inflammation occur in the white matter of the CNS. The findings of many epidemiological studies and a discordance of MS in monozygotic twins suggest that the disorder is acquired. The most likely cause is a virus because more than 90% of patients with MS have high concentrations of IgG, manifest as oligoclonal bands, in the brain and CSF. Most chronic inflammatory CNS disorders are infectious. More indirect evidence that MS is caused by a virus is the association of several viruses with demyelinating encephalomyelitis in human beings, and the induction of demyelination in animals infected with viruses in research. Nevertheless, no virus has been isolated from the brains of patients who had MS. Molecular analysis of IgG gene specificity in the brain and CSF of those with MS has shown features of an antigen-driven response: clonal amplification and extensive somatic mutations. A viral antigen against which the IgG in MS brain and CSF is directed might be identified.

B cells in multiple sclerosis

The most common laboratory abnormality in multiple sclerosis (MS) is an increased amount of cerebrospinal fluid IgG and the presence of oligoclonal bands. Despite studies of the humoral response that suggest the involvement of an infectious agent or autoantigen in disease, the major targets of the oligoclonal response are still unknown. Identification of these targets will reveal valuable insights into the cause and pathogenesis of MS and is likely to lead to effective treatment.

Oligoclonal immunoglobulins in cerebrospinal fluid during varicella zoster virus (VZV) vasculopathy are directed against VZV

Limited analyses of cerebrospinal fluid from patients with central nervous system infections have shown that the oligoclonal IgG is antibody directed against the agent that causes disease. Using a new method involving binding of IgG to beads coated with lysates prepared from candidate infectious antigens, we showed that the oligoclonal IgG in cerebrospinal fluid of a patient with chronic varicella zoster virus vasculopathy is directed against the causative virus. This approach holds promise in identifying and purifying the relevant oligoclonal IgGs in inflammatory central nervous system diseases of unknown cause.

A search for virus in multiple sclerosis

It is the stepwise accumulation of scientific information that allows the rare breakthrough which forever changes our understanding of a disease process. This paper begins with a review of the history of great experiments initiated in the 1960s which showed that multiple chronic neurological diseases were transmissible and in some instances were caused by a virus. Such an historical perspective combined with the rationale for the viral etiology of MS described herein, led Dr. Hilary Koprowski to organize a team of clinicians, pathologists, cell biologists, virologists, and immunologists to obtain MS brain, propagate MS brain cells in tissue culture, and to analyze cells for productive or latent infection. No virus was found with the state-of-the-art techniques available in the 1970s. However, currently available molecular biologic strategies and techniques allow virus detection not possible 30 years ago. These studies could confirm Dr. Koprowski's prophetic vision and identify the virus that causes MS, including the mechanism by which demyelination is produced.

Cloning the Antibody Response in Humans with Inflammatory Central Nervous System Disease: Analysis of the Expressed IgG Repertoire in Subacute Sclerosing Panencephalitis Brain Reveals Disease-Relevant Antibodies That Recognize Specific Measles Virus Antigens

The presence of increased IgG in the brains of humans with infectious and inflammatory CNS diseases of unknown etiology such as multiple sclerosis may be a clue to the cause of disease. For example, the intrathecally synthesized oligoclonal bands (OGBs) in diseases such as subacute sclerosing panencephalitis (SSPE) or cryptococcal meningitis have been shown to represent Ab directed against the causative agents, measles virus (MV) or Cryptococcus neoformans, respectively. Using SSPE as a model system, we have developed a PCR-based strategy to analyze the repertoire of IgG V region sequences expressed in SSPE brain. We observed abnormal expression of germline V segments, overrepresentation of particular sequences that correspond to the oligoclonal bands, and substantial somatic mutation of most clones from the germline, which, taken together, constitute features of Ag-driven selection in the IgG response. Using the most abundant or most highly mutated γ H chain and κ or lambda L chain sequences in various combinations, we constructed functional Abs in IgG mammalian expression vectors. Three Abs specifically stained MV-infected cells. One Ab also stained cells transfected with the MV nucleoprotein, and a second Ab stained cells transfected with the MV-fusion protein. This technique demonstrates that functional Abs produced from putative disease-relevant IgG sequences can be used to recognize their corresponding Ags.

Cloning the antibody response in humans with inflammatory CNS disease: isolation of measles virus-specific antibodies from phage display libraries of a subacute sclerosing panencephalitis brain

We have developed a strategy to identify the disease-relevant antigens in a chronic inflammatory CNS disease exhibiting intrathecally expressed oligoclonal IgG. Using subacute sclerosing panencephalitis (SSPE), a chronic inflammatory measles virus infection of the brain as a model system, we constructed a phage display antibody Fab library from the amplified products of IgG expressed in the brain. Selection of the library against measles virus-infected cell lysates yielded four distinct Fabs which, by ELISA and by immunostaining, reacted specifically with measles virus-infected cells. Three Fabs immunoprecipitated a 72 kDa protein from infected cell cultures corresponding to the measles virus phosphoprotein. The fourth Fab immunoprecipitated and recognized by immunoblotting a 60 kDa protein corresponding to the measles virus nucleoprotein. The results demonstrate that functional antibodies from an inflammatory CNS disease can be expressed in bacteria and used to identify disease-relevant antigens. This approach could be applied to chronic inflammatory CNS diseases of unknown cause such as multiple sclerosis.

Extraction and purification of active IgG from SSPE and MS brain

Immunoglobulin (Ig) G was purified from soluble and membrane fractions of postmortem subacute sclerosing panencephalitis (SSPE) brain, multiple sclerosis (MS) brain plaque-periplaque white matter, and normal human brain (NHB) white matter. After homogenization in 0.32 M sucrose and removal of cell debris and nuclei by low-speed centrifugation, soluble and crude membrane fractions were separated by ultracentrifugation. After removal of sucrose by dialysis, IgG was isolated from the soluble fraction by protein A affinity chromatography. IgG was obtained from the membrane fraction by elution at low pH and purification from the eluate by protein A chromatography. Whereas very little IgG was in NHB white matter, significant levels of IgG were recovered from both SSPE and MS brain. Both immunocytochemical staining of measles virus-infected cells in tissue culture and protein immunoblotting of virus-infected cell lysates showed that the IgG from SSPE brain contained activity specific for measles virus protein. The abundance, purity and functional activity of IgG extracted from SSPE and MS brain indicate that IgG extracted from the brain of humans with an inflammatory disease of unknown etiology can be used to identify its corresponding antigen.

Cerebrospinal fluid analysis in clinical diagnosis

Images

The search for virus in multiple sclerosis brain

Plaque-periplaque areas from MS brain tissue were explanted and propagated in tissue culture. The same in vitro techniques that successfully rescued measles virus from SSPE brain, papovavirus from PML brain, and HSV from normal human trigeminal ganglia, were applied. MS brain cells were also inoculated into chimpanzees, multiple rodent species, and embryonated hens eggs. No neurologic disease developed in experimentally infected animals, and no cytopathic effect was observed in explanted cells, or after cocultivation or fusion of MS brain cells with indicator cells. Further analysis of explanted and cocultivated cells by indirect immunofluorescence with various antiviral antisera prepared against viruses associated with post-infectious encephalomyelitis, as well as antisera to other ubiquitous viruses, failed to detect viral antigen. Finally, attempts to detect a latent enveloped virus in MS brain cells by 'superinfecting' MS brain cells in culture with vesicular stomatitis virus (VSV) did not reveal a VSV non-neutralizable fraction. Nevertheless, since oligoclonal bands (OGBs) in the CSF of patients with chronic infectious diseases of the CNS are directed against the causative agent, it is likely that OGBs in MS CSF are antibody directed against the agent or antigen that triggered disease. Although the relevant antibody may be scarce relative to irrelevant antibody in MS CSF, and only small amounts of an MS-specific antigen may be present in brain, this report provides a rationale for strategies proposed in our companion report by Owens et al which will allow detection of an MS-specific antigen or its cognate RNA in brain.

Evidence for locally synthesized and clonally restricted immunoglobulin in the synovial fluid from rheumatoid arthritis patients

In this study, we examined the immunoglobulin (Ig) present in synovial fluid (SF) from patients with rheumatoid arthritis (RA) to determine if it was locally produced and to assess the presence of clonally restricted (oligoclonal) immunoglobulin. We studied SF/serum pairs from 55 RA patients and 23 patients with degenerative joint disease (DJD). We found increases in total protein, IgG, IgA, and IgM in RA vs DJD SF (P less than 0.01). The immunoglobulin present in RA appeared to be locally produced as evidenced by significant increases (P less than 0.01) in the immunoglobulin indices. Regression analysis among the levels of IgG, IgA, and IgM RF and the Ig indices suggested that only a minority of the locally synthesized Ig present was specific for RF. To provide evidence of clonal restriction, we further analyzed the SF specimens by isoelectric focusing and assessed the presence of oligoclonal bands present only in RA SF. In 7/55 RA specimens (13%) we found unique SF IgG bands. All bands were of similar isoelectric point (pI), being quite cathodic with pI greater than 7.5. Our evidence supports synthesis of Ig within RA synovium, with a minority of patients showing prominent and unique SF Ig bands. This suggests an oligoclonal response in SF of some patients, but polyclonal Ig synthesis in most.

Serologic studies in the diagnosis and management of meningitis due to Sporothrix schenckii

Eight patients have previously been reported to have central nervous system infections caused by Sporothrix schenckii. In those patients the fungus proved quite difficult to culture, delaying correct diagnosis and treatment. We describe seven additional patients with sporotrichosis meningitis, all of whom had antibody to this fungus in cerebrospinal fluid and serum. The antibody in the cerebrospinal fluid was most likely produced locally, as evidenced by its oligoclonality and the relatively high ratio of immunoglobulin to albumin in the cerebrospinal fluid as compared with the serum. Only one of these seven patients, who had active sporotrichosis of the knee joint, had obvious extrameningeal infection. None of 130 patients with meningitis known to be caused by other agents and none of 170 patients with other neurologic disorders had antibody to S. schenckii in their cerebrospinal fluid. We suggest that cerebrospinal fluid should be tested for S. schenckii antibody (in addition to other fungal agents) in any patient with chronic meningitis for which no cause is discovered by the usual diagnostic tests.

Cryptococcal meningoencephalitis: intrathecal immunological response

The intrathecal immune response is reported in a patient with cryptococcal meningoencephalitis. CSF IgM and IgG levels were significantly related to the favourable clinical evolution. IgM response was specifically directed against the pathological agent, while IgG were mostly non-specific. The data are discussed and compared with the other chronic infections of the central nervous system.

Oligoclonal immunoglobulin bands in cerebrospinal fluid of a patient with lymphocytic choriomeningitis

We describe a patient with meningitis caused by lymphocytic choriomeningitis virus. Oligoclonal IgG bands were found in the patient's cerebrospinal fluid during acute and convalescent stages of the illness, and results of liver function tests were abnormal. Acute attacks of lymphocytic choriomeningitis virus infection in humans can be added to the list of diseases associated with cerebrospinal fluid oligoclonal IgG.

Synthesis of electrophoretically restricted IgG by cultured rheumatoid synovium

IgG synthesized by excised rheumatoid (RA) synovia was separated according to isoelectric point using chromatofocusing and isoelectric focusing. Over 30% of the IgG synthesized by 9 of 11 synovia had an isoelectric point greater than 8 (cathodal shift), while 55% of the synovia secreted IgG showing oligoclonal banding by isoelectric focusing. Oligoclonal serum IgG was seen in 17% of RA patients and in only 3% of hospitalized patients without RA. These results emphasize the selective character of the antigenic stimulus of the RA synovial lymphoid infiltrate.

Occurrence of oligoclonal bands in multiple sclerosis and other CNS diseases

The results of cerebrospinal fluid agarose gel electrophoresis in 300 consecutive patients were correlated with neurological examinations and diagnoses, other cerebrospinal fluid studies, and the results of evoked potential examinations. The presence of oligoclonal bands was the most sensitive test for multiple sclerosis (MS); bands were present in from 100% (11/11) of patients with definite MS to 82% (27/33) of those with possible MS (classified by McAlpine criteria). The visual evoked response was the next most sensitive study. Thirty-eight patients without MS or related disorders had bands in the IgG region. Three patients had plasma cell dyscrasias. Seven patients had thick single bands. Single bands did not correlate with chronic polyneuropathy but appeared to be an artifact of storage. Twenty-eight patients had active neurological disease, including cerebral infarction (in 5), viral infection (in 4), remote effect of carcinoma (in 4), and acute and chronic polyneuropathies (in 6). In acute illnesses (i.e., vascular insults), repeat electrophoresis showed disappearance of bands. In continually active disease, bands persisted. These results indicate that the presence of oligoclonal bands provides sensitive supporting evidence for the diagnosis of MS but that bands may be present in other disorders, including those not directly related to infection or abnormal immune response. The data suggest that oligoclonal bands may represent an immune response to neurological injury that is prominent in disorders with a particularly intense or continuous antigenic stimulus.

Intrathecal synthesis of virus-specific oligoclonal IgG, IgA and IgM antibodies in a case of varicella-zoster meningoencephalitis

Varicella-zoster (VZ) virus meningoencephalitis was diagnosed in a 72-year-old man without other clinical signs of VZ infection, on the basis of intrathecal virus-specific IgG, IgA and IgM antibody responses demonstrated by imprint immunofixation (IIF) and by serological analyses of serum and CSF. The intrathecally produced antibodies displayed oligoclonal characteristics. The intrathecal production of VZ-IgG and -IgA antibodies persisted throughout the observation period of 20 months, while that of VZ-IgM antibodies was not detectable later than 3 months after onset. Part of the intrathecally produced VZ-IgG and -IgA antibody populations, but no IgM antibodies, were shown to cross-react with herpes simplex virus. Oligoclonal IgG bands were demonstrated in the CSF throughout the observation period. The bulk of the IgG bands was shown to represent VZ-specific antibodies.

Herpes simplex virus encephalitis: intrathecal synthesis of oligoclonal virus-specific IgG, IgA and IgM antibodies

Paired specimens of serum and CSF from seven patients with acute herpes simplex virus encephalitis were examined during the acute illness or the convalescent stage or during both stages. Imprint immunofixation analyses of viral antibodies separated by agarose electrophoresis and by electrofocusing disclosed intrathecal production of herpes simplex virus IgG antibodies in all seven patients, and of IgA and IgM antibodies in six and three of six patients, respectively. Intrathecal production of herpes simplex virus-specific IgG and IgA was observed in two patients from whom samples were collected after 1 year, while intrathecal production of virus-specific IgM was not demonstrated later than 5 weeks after onset. The intrathecally synthesized IgG and IgM, and to a lesser extent IgA antibodies displayed oligoclonal characteristics. Oligoclonal bands of IgG were observed in the CSF of all patients. Evidence is presented to show that the bulk of the oligoclonal CSF IgG represents herpes simplex virus-specific antibodies. Intrathecally synthesized populations of herpes simplex virus antibodies cross-reacting with varicella-zoster virus were identified in three of the patients.

Multiple sclerosis. Electrofocused "bands" of oligoclonal CSF IgG do not carry antibody activity against measles, varicella-zoster or rotaviruses

Electrofocused serum and cerebrospinal fluid (CSF) specimens from patients with multiple sclerosis (MS) were analysed for immunoglobulins (Ig) and for antibodies to measles, varicella-zoster and rotaviruses by an imprint immunofixation method. Patterns of intrathecally synthesized antibodies to the 3 viruses differed from patterns of oligoclonal IgG in the CSF. A variable proportion of virus antibody bands (average 19% for measles antibodies, 8% for varicella-zoster antibodies, 31% for rotavirus antibodies) displayed isoelectric points identical to bands of IgG, but absorption with measles, varicella-zoster and rotavirus antigens produced no change in the bands of IgG and no quantifiable decrease of the CSF IgG. The results confirm previous evidence that the intrathecally synthesized viral antibodies so far demonstrated in MS are not carried by the oligoclonal bands of CSF IgG and account for only a minor fraction of the CSF IgG.

The use and abuse of the cerebrospinal fluid IgG profile in the adult: a practical evaluation

Cerebrospinal fluid (CSF) samples from 150 patients with multiple sclerosis (MS) and 190 patients with other neurological disorders were examined with a battery of tests (the IgG profile) to detect quantitative and qualitative abnormalities in CSF IgG. The CSF IgG profile consisted of an IgG/albumin (IgG/alb) ratio, an IgG index, and examination by agarose gel electrophoresis (AGE) and isoelectric focusing (IF) to detect oligoclonal bands. The tests were compared for diagnostic accuracy, including false-positive results. The IgG/alb ratio was less reliable in confirming the diagnosis of MS, but no significant difference in accuracy was found among the other three methods. IF tended to identify more possible and probable MS cases than did AGE but gave a higher rate of false-positives. The IgG index and IgG synthesis rates showed no significant difference in their ability to identify MS patients. Steroid administration decreased the incidence of abnormal IgG/alb ratios and IgG indices, but not abnormal oligoclonal bands. Central nervous system (CNS) infections or immunological diseases involving the CNS produced a 28 to 40% incidence of abnormalities in the CSF. Neither the patient's age, sex, duration of illness, activity of disease, nor longitudinal course correlated with the CSF findings. A few (1%) control neurological patients had all components in the CSF IgG profile abnormal. For most routine clinical purposes the IgG index and AGE are sufficient for confirmation of diagnosis, and the IgG index was the best single test in our series.