Evaluation of immunoglobulin M (IgM) and IgG enzyme immunoassays in serologic diagnosis of West Nile Virus infection

A unique urban encephalitis epidemic in Romania signaled the emergence of neurological infection due to West Nile (WN) virus as a novel public health threat in Eastern Europe and provided an opportunity to evaluate patterns of immunoglobulin G (IgG) and IgM reactivity in IgM capture and IgG enzyme-linked immunosorbent assays (ELISAs). WN virus infection was diagnosed serologically in 236 of 290 patients from whom acute serum or cerebrospinal fluid (CSF) samples were available. In 37% of serum samples and in 25% of CSF samples collected in the first week of illness, anti-WN virus IgM antibody was detected in the absence of virus-specific IgG. The switch to an IgG antibody response occurred after 4 to 5 days of illness and earlier in CSF than in serum. A specific humoral immune response was detected in the CSF before the serum in some patients for whom paired CSF and serum samples from the same day were available. IgM antibody in convalescent serum samples persisted beyond 2 months after the onset of illness in more than 50% of patients. ELISA optical density values and antibody concentrations were well correlated for both IgM and IgG immunoassays. Anti-WN virus IgM antibody in acute-phase samples did not cross-react significantly with flaviviruses in other antigenic groups.

Clinical observations on eosinophilic meningitis and meningoencephalitis caused by Angiostrongylus cantonensis on Taiwan

One hundred and twenty-five patients with eosinophilic meningitis or meningoencephalitis were studied in southern Taiwan in 1968 and 1969. The majority of patients had mild to moderate disease, but several had severe manifestations. Four patients died and three others had severe permanent sequelae such as blindness. Young adult Angiostrongylus cantonensis were recovered from nine patients, at autopsy in one, and from the cerebrospinal fluid of eight who survived. The clinical manifestations of cases of proven etiology were similar to those of cases from which parasites were not recovered and it is believed that the latter also were the result of infection with A. cantonensis.

Oligoclonal T lymphocytes in the cerebrospinal fluid of patients with multiple sclerosis

We have investigated the T cell populations in the cerebrospinal fluid (CSF) of chronic progressive multiple sclerosis (MS) patients. Individual T cells from the CSF and blood were cloned before expansion and their clonotypes were defined by analysis of rearranged T cell receptor beta chain and gamma chain genes. 87 T cell clones from blood and CSF of two patients with chronic progressive MS were examined for common TCR gene rearrangement patterns. In one patient, 18 of 28 CSF-derived T cell clones demonstrated common TCR gene rearrangements indicating oligoclonal T cell populations; in the blood, two patterns were found twice among 26 T cell clones. In another patient, 5 of 27 CSF-derived clones had common TCR gene rearrangement patterns. In contrast, no common beta chain rearrangement pattern was found among 67 T cell clones derived from the blood or CSF of a patient with subacute sclerosing panencephalitis, among 20 clones from the CSF of a patient with herpes zoster meningoencephalitis, or among 66 clones from a normal subject. A subject with atypical, fatal MS of 8-mo duration was also studied and did not have oligoclonal T cells in the CSF or blood. These results demonstrate that distinct oligoclonal T cell populations can be found in the CSF immune compartment of subjects with nonmalignant inflammatory disease and they can create a new avenue for the investigation of the specificity of the T cell response within the central nervous system.

Neuron-specific enolase and S-100 protein levels in cerebrospinal fluid of patients with various neurological diseases

Neuron-specific enolase (NSE) and S-100 protein (S-100) levels in cerebrospinal fluid (CSF) were determined in 129 patients with various neurological diseases. The chronological changes of these nervous system-specific proteins in CSF were also examined in 3 patients with acute disorders. NSE and S-100 levels were elevated in many cases with acute conditions. These specific proteins did not increase simultaneously but independently. These results suggested that NSE and S-100 in CSF would be useful markers for damage of the nervous system and that measurement of both NSE and S-100 might positively indicate whether the damage was neuronal, glial or mixed in origin. Moreover, from the serial determination of these substances, they would be better markers than cell counts and total protein in CSF for the active injury for the nervous tissues.

Matrix metalloproteinase-9 is elevated in serum of patients with amyotrophic lateral sclerosis

Matrix metalloproteinase-9 (MMP-9) and its specific inhibitor, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), were analysed by enzyme-linked immunosorbent assay (ELISA) and by zymography in serum and cerebrospinal fluid (CSF) of patients with amyotrophic lateral sclerosis (ALS). In contrast to patients with inflammatory diseases, MMP-9 levels were not elevated in CSF of ALS patients. In serum, however, compared to healthy donors, MMP-9 was significantly (p = 0.0003) increased up to levels as high as those of viral meningoencephalitis (VM) or bacterial meningitis (BM) patients. MMP-9 levels remained elevated during long-term observation of ALS patients. In the absence of an inflammatory response, the results indicate that the increase of MMP-9 in serum of ALS patients might be caused by upregulation of MMP-9 in denervated muscles or in degenerating peripheral nerves following motor neurone loss.

Clinical findings of West Nile virus infection in hospitalized patients, New York and New Jersey, 2000

Outbreaks of West Nile (WN) virus occurred in the New York metropolitan area in 1999 and 2000. Nineteen patients diagnosed with WN infection were hospitalized in New York and New Jersey in 2000 and were included in this review. Eleven patients had encephalitis or meningoencephalitis, and eight had meningitis alone. Ages of patients ranged from 36 to 87 years (median 63 years). Fever and neurologic and gastrointestinal symptoms predominated. Severe muscle weakness on neurologic examination was found in three patients. Age was associated with disease severity. Hospitalized cases and deaths were lower in 2000 than in 1999, although the case-fatality rate was unchanged. Clinicians in the Northeast should maintain a high level of suspicion during the summer when evaluating older patients with febrile illnesses and neurologic symptoms, especially if associated with gastrointestinal complaints or muscle weakness.

Isolation and characterization of two parasitic protozoa from a Pacific harbor seal (Phoca vitulina richardsi) with meningoencephalomyelitis

Two species of protozoans were isolated from a harbor seal with fatal meninogoencephalitis. Serologic reactivity was detected to both Sarcocystis neurona and Toxoplasma gondii. Parasites associated with brain inflammation and necrosis reacted only with immunohistochemical stains utilizing polyclonal antisera raised against Sarcocystis neurona. However, 2 distinct parasites were observed in cell cultures derived from the seal's brain tissue. These parasites were separated by mouse passage and limiting dilution. Purified zoites from 1 isolate (HS1) reacted strongly with polyclonal antiserum to S. neurona and with the harbor seal's own serum (1:2,560 for each) on indirect immunofluorescent antibody tests (IFAT), but weakly to antisera to T. gondii and Neospora caninum (1:40). Zoites from the second isolate (HS2) reacted positively with T. gondii polyclonal antiserum (1:81,920) and with the harbor seal's own serum (1:640), but weakly to S. neurona and N. caninum antisera (1:80 or less). Amplification and sequence analysis of protozoal DNA encoding portions of the 18s ribosomal RNA (18s rDNA) and the adjacent first internal transcribed spacer (ITSI) were performed for both isolates, and resulting sequences were compared to those from similar protozoans. Based on molecular characterization, parasite morphology, serologic reactivity, histology, and immunohistochemistry, HS1 was indistinguishable from S. neurona, and HS2 was indistinguishable from T. gondii.

A necrotizing meningoencephalitis of pug dogs

Clinical and pathologic features of a sporadic, necrotizing meningoencephalitis affecting adolescent and mature pug dogs are described. Many of the affected animals were closely related. Acute and chronic forms occur, with clinical signs reflecting the pathologic affinity of the disease for the cerebral hemispheres. No etiologic agent has been identified. The extensive necrosis and affinity for the cerebral hemispheres are similar to alphatype herpesvirus encephalitides of other species.

Detection of virus in CSF from the cases with meningoencephalitis by next-generation sequencing

We screened for viral DNA in cerebrospinal fluid samples using next-generation sequencing (NGS) technology to diagnose CNS viral infections. We collected CSF samples from four cases with clinically suspected viral meningoencephalitis. DNA extracted from the samples was analyzed with NGS, and the results were further validated using PCR. Herpes simplex virus 1 (HSV-1) was detected in the CSF of two patients, HSV-2 and human herpes virus type 3 (HHV-3, VZV) in the CSF of two other patients separately. The number of unique reads of the identified viral genes ranged from 144 to 44205 (93.51 to 99.57%). The coverage of identified viral genes ranged from 12 to 98% with a depth value of 1.1 to 35, respectively. The results were further confirmed using PCR in three cases. The clinical presentation and outcomes of these four cases were consistent with the diagnostic results of NGS. NGS of CSF samples can be used as a diagnostic assay for CNS viral infection. Its further application for "pan-viral" or even "pan-microbial" screening of CSF might influence the diagnosis of CNS infectious diseases.

Measurement of prostaglandin F2alpha levels in human cerebrospinal fluid in normal and pathological conditions

Prostaglandin F2alpha concentrations were measured in human cerebrospinal fluid by the gas-chromatography-mass spectrometric technique using 2-H4-PGF2 alpha as internal standard and carrier. Normal levels of 71.6 plus or minus 34.7 pg/ml were found. Considerable increases in PGF2 alpha concentrations were found in patients with epilepsy, meningtitis or following cerebrovascular accidents or neurosurgical removals of brain tissue. The results agree in general with recent measurements using radioimmunoassay.

Aseptic meningoencephalitis in primary Sjögren's syndrome

The clinical features and CSF characteristics of five patients with primary Sjögren's syndrome (SS) and associated aseptic meningoencephalitis (AME) are described. Episodes of AME were recurrent in four patients. Viral, fungal, and bacterial cultures were uniformly negative. Plasma cells were observed in the CSF but not in the blood of three patients. The CSF IgG:albumin index was elevated, suggesting intrathecal synthesis of IgG in each of the four patients tested; each patient had either one or two broad bands with the mobility of IgG on CSF agarose electrophoresis. These observations are consistent with current understanding of SS as a polyclonal gammopathy associated with the multifocal proliferation of B lymphocytes and plasma cells.

Primary infection, latency, and reactivation of bovine herpesvirus type 5 in the bovine nervous system

Bovine herpesvirus type 5 (BHV-5) infection in calves causes meningoencephalitis, a fatal disease highly prevalent in South America. To study the pathogenesis of BHV-5 infection in cattle, 12 calves (group 1: acute infection) and 11 calves (group 2: latent infection) were intranasally inoculated with an Argentinean BHV-5 isolate at 10(8) and 10(4.7) tissue culture infective doses, respectively; six calves (control group) were mock infected. At 3 months postinoculation, all of the calves in group 2 and three calves in group 3 were given dexamethasone to reactivate the virus. The animals were euthanatized between days 6 and 17 postinoculation (group 1) and between days 6 and 16 postreactivation (group 2). Seventy-five percent and 91% of animals in groups 1 and 2, respectively, excreted BHV-5 in nasal and ocular discharges. Following dexamethasone administration, 45% of calves shed virus in both types of secretions. Spontaneous virus reactivation and shedding was observed in one calf. Neurologic signs consisting of circling, teeth grinding, ptyalism, jaw chomping, tongue protrusion, and apathy were observed in two animals in group 1 and, during the reactivation period, in four animals in group 2. Macroscopic findings consisted of softening of the cerebral tissue, meningeal hemorrhages and swelling, and edema and hemorrhages of prescapular, retropharyngeal and submandibular lymph nodes. Histologic lesions consisted of meningitis, mononuclear perivascular cuffing, neuronophagia, satellitosis, gliosis, hemorrhage, and necrosis and edema. Lesions in anterior cerebral cortex, medulla, and pons were consistently seen in all the animals of group 1. In the acutely infected animals, lesions in the diencephalon appeared at day 10 postinoculation, whereas in the latently infected calves these lesions were observed as early as at day 6 postreactivation. Latently infected animals developed lesions simultaneously in anterior cortex, medulla, pons, and diencephalon, showing a remarkable difference from the acutely infected group. Trigeminal ganglionitis appeared relatively early in animals of both groups (day 7 postinoculation in group 1 and day 8 postreactivation in group 2).

The concentration of IgM in the cerebrospinal fluid of neurological patients

The level of IgM was determined by Particle Counting Immunoassay in the cerebrospinal fluid. In non-neurological patients (N = 20) the mean was 97.5 micrograms/l with the upper reference limit at 380 micrograms/l. The mean IgM index was 0.021 with the upper reference limit at 0.071. Of 21 patients with stroke, 5 had an IgM index exceeding the reference limit. High levels and indices of IgM were observed in most patients (N = 27) with infectious meningo-encephalitis. In this group, the IgM index was abnormal in about 30% of cases with a normal total protein content, and was more often increased than the IgG index. In multiple sclerosis patients (N = 80), the IgM index was increased in 32%. In this disease very high values of IgM index (greater than 0.13) were never associated with very high values of IgG index (greater than 1.8). A significantly higher proportion of males was found in the group of patients with very high values of IgM index (N = 11). No significant influence of the age of onset, the interval between onset and sampling and clinical state was observed. However, of 10 patients with a multiple sclerosis history exceeding 15 years none had an IgM index exceeding the upper reference limit. Four patients with multiple sclerosis had a high IgM index without either an increase of the IgG index or the presence of oligoclonal bands.

Cerebrospinal fluid concentrations of interleukin-1 beta, tumour necrosis factor-alpha, and interferon gamma in bacterial meningitis

To investigate the role of the inflammatory cytokines, the cerebrospinal fluid concentrations of interleukin (IL)-1 beta, tumour necrosis factor-alpha (TNF-alpha), and interferon gamma (IFN-gamma) were measured in 11 children with bacterial meningitis and two with mycoplasmic meningoencephalitis and compared with those in 50 children with aseptic meningitis and 15 with non-pleocytotic cerebrospinal fluid. Concentrations of IL-1 beta and TNF-alpha were each significantly higher in the cerebrospinal fluid of patients with bacterial meningitis than in those with aseptic meningitis or those with non-pleocytotic cerebrospinal fluid. IFN-gamma was detected at low concentrations in the cerebrospinal fluid of only 2/11 of those with bacterial meningitis. On the other hand, the IFN-gamma concentration was the highest in the cerebrospinal fluid of patients with aseptic meningitis. These results suggest that the inflammatory cytokines are differently released in the intrathecal space infected with viruses or bacteria.

Value of cerebrospinal fluid analysis in the differential diagnosis of meningitis: a study in 710 patients with suspected central nervous system infection

A prospective study to determine the value of cerebrospinal fluid analysis in the differential diagnosis of meningitis was performed in 710 consecutively observed patients, both children and adults, who underwent lumbar puncture due to suspected central nervous system infection. Diagnoses included acute or presumed bacterial meningitis (n = 79), acute or presumed viral meningoencephalitis (n = 218), acute unclassified meningitis (n = 6), other infections of the central nervous system (n = 37), non-infectious neurological diseases (n = 76) and control patients (n = 294). The sensitivity, specificity and predictive values were determined for cerebrospinal fluid white blood cell count, total protein, lactate, glucose and C-reactive protein levels as well as the blood/cerebrospinal fluid glucose ratio. Determination of cerebrospinal fluid levels of lactate (greater than or equal to 3.5 mmol/l) was found to be superior to the other tests. The C-reactive protein level gave no additional diagnostic information when the lactate level was determined. The white blood cell count, and total protein and glucose levels were often unreliable tools for differential diagnosis, largely due to low sensitivity at realistic discriminatory limits. The study confirms that no cerebrospinal fluid test is fully reliable in distinguishing bacterial meningitis from other forms of meningitis.

Marked increase of matrix metalloproteinase 9 in cerebrospinal fluid of patients with fungal or tuberculous meningoencephalitis

Matrix metalloproteinases (MMPs) are believed to play an essential role in the breakdown of the extracellular matrix macromolecules in the blood-cerebrospinal fluid barrier and blood-brain barrier (BBB). In this study, the levels of MMP-2 and MMP-9 and their common tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) were measured in the cerebrospinal fluid (CSF) from patients with various meningitides including aseptic, fungal and tuberculous ones. MMP-9 production level in CSF was more increased in subacute meningitis including fungal and tuberculous meningitis than in acute aseptic meningitis and non-inflammatory neurological diseases (NIDs). Enhanced production of MMP-9 was associated with high proteolytic activity detected by gelatin zymography. The MMP-2 and TIMP-1 levels in CSF of subacute meningitis were also higher than those of NIDs. In contrast, the TIMP-2 levels in CSF of either acute aseptic or subacute meningitis were not up-regulated compared with those of NIDs. The central nervous system (CNS) complications (i.e. disturbance of consciousness, psychiatric symptoms, urinary disturbance, etc.) during the course of meningitis showed good correlation with the enhanced production of MMP-9 in CSF. Immunohistochemical studies in tuberculous meningitis demonstrated that the infiltrating mononuclear cells in the meninges were immunoreactive for both MMP-2 and MMP-9. However, the infiltrating mononuclear cells into CNS parenchyma had immunoreactivity for MMP-9, but not for MMP-2. Taken together, those data suggest that MMP-9 in CSF may be a useful marker of encephalitogenecity during the course of subacute meningitis.

Nonvasculitic autoimmune inflammatory meningoencephalitis (NAIM): a reversible form of encephalopathy

Five patients, age 54 to 80 years, presented between 3 weeks and 18 months after symptomatic onset of progressive cognitive decline, psychosis, and unsteady gait that proved to be due to a steroid-responsive nonvasculitic autoimmune inflammatory meningoencephalitic syndrome. CSF examination showed elevated immunoglobulin (Ig)G index and IgG synthesis rate in all three patients in whom it was checked, and brain biopsy revealed perivascular lymphocytic infiltrates without vessel wall invasion.

Serum and CSF levels of soluble intercellular adhesion molecule-1 (ICAM-1) in inflammatory neurologic diseases

Intercellular adhesion molecule-1 (ICAM-1), a cell surface receptor important for cellular interactions in immune responses, especially leukocyte trafficking into inflamed tissue, is released in a soluble form (sICAM-1) into the extracellular space. In this study, we measured sICAM-1 in paired serum and CSF samples from patients with inflammatory diseases of the nervous system (IND) and calculated a sICAM-1 index as a measure of the intrathecal release of ICAM-1. In comparison with noninflammatory neurologic disease (NIND) controls, we found increased sICAM-1 index levels in viral meningoencephalitis, bacterial meningitis and, to a lesser degree, multiple sclerosis but not in Guillain-Barré syndrome. Serial examination of viral meningoencephalitis patients in most cases showed a decrease of sICAM-1 index in parallel with falling cell counts and clinical improvement. Except for those in bacterial meningitis, sICAM-1 serum levels of IND patients were not significantly different from those of NIND controls. The increased intrathecal release of sICAM-1 in viral meningoencephalitis and bacterial meningitis most likely reflects activation of macrophages and lymphocytes and provides evidence for a strong local immune response that itself, in addition to the infectious agent, may damage nervous tissue.

Fatal fulminant pan-meningo-polioencephalitis due to West Nile virus

We report a case of fatal fulminant West Nile virus (WNV) meningoencephalitis in an 87-year-old white male gardener. The Pennsylvania patient presented with a 3-day history of flu-like symptoms. His hospital course was gravely precipitous with onset of coma, ventilator dependence, loss of cortical and brainstem functions within ten days of admission. Acute serum and cerebrospinal fluid samples revealed elevated levels of WNV IgM antibodies by ELISA as well as elevated CSF white blood cells, protein and glucose. A complete autopsy revealed a multifocal lymphocytic myocarditis and severe chronic tubulointerstitial nephritis. Viral culture and PCR analysis of post-mortem samples of the spleen, kidney and brain were positive for WNV. Histological sections from all regions of the brain and spinal cord demonstrated a severe, non-necrotizing, subacute, polio-meningoencephalitis. While both gray and white matter were inflamed, gray matter was much more severely involved. Many gray matter nuclei showed severe neuronal loss with residual dying neurons surrounded by activated microglia. Immunohistochemical stains revealed profuse infiltration of the meninges and cerebral parenchyma by CD8 T-lymphocytes and perivascular B-lymphocytes. Electron micrographs revealed diffuse intracellular and extracellular edema but no viral particles were identified. Immunohistochemical and immunofluorescent staining for WNV filled the cytoplasm of residual neurons. West Nile virus mediates a predominantly polioencephalitis secondary to direct infection of neurons.

Persistent enterovirus infection in culture-negative meningoencephalitis: demonstration by enzymatic RNA amplification

Chronic meningoencephalitis due to enterovirus infection can occur in patients with antibody deficiencies. A modified polymerase chain reaction technique demonstrated persistent echovirus 11 infection in such a patient, despite negative routine viral cultures and negative routine nucleic acid hybridization. Although the sequence of echovirus 11 has not yet been determined, genomic conservation among the enteroviruses is significant, permitting detection of echovirus 11 with a primer pair and probe derived from enterovirus serotypes that have been fully sequenced. This study provides the first definitive evidence for the persistence of enterovirus infection with negative viral cultures.

Acute CNS infection by Trypanosoma cruzi (Chagas' disease) in immunosuppressed patients

Acute CNS involvement by Trypanosoma cruzi is uncommon. We report 2 immunosuppressed patients, 1 adult who developed an acute meningoencephalitis, and 1 child who presented with the tumor-like form of the disease. Both patients acquired the disease through blood transfusion. Blood donors migrating from endemic areas can transmit the disease in nonendemic countries if they are not routinely screened for antibodies to T cruzi.

Diagnosis and management of Baylisascaris procyonis infection in an infant with nonfatal meningoencephalitis

Baylisacaris procyonis, the common raccoon ascarid, is known to cause life-threatening visceral, neural, and ocular larva migrans in mammals and birds. Two human fatalities have been previously described; however, little is known about the spectrum of human disease caused by B. procyonis. In this report, the case of a 13-month-old child who had nonfatal meningoencephalitis secondary to B. procyonis infection is presented. The suspected diagnosis was confirmed with use of newly developed enzyme immunoassay and immunoblot techniques. The diagnosis, management, and prevention of B. procyonis infection in humans is discussed. Clinical, serological, and epidemiological evaluations established B. procyonis as the etiologic agent. The child survived his infection but continued to have severe neurological sequelae. The potential for human contact and infection with B. procyonis is great. There is no effective therapy; therefore, prevention is paramount.

Interferon-gamma-inducing factor (IL-18) and interferon-gamma in inflammatory CNS diseases

OBJECTIVE

To examine the intrathecal production of a newly identified cytokine, interferon-gamma-inducing factor (IL-18), together with interferon-gamma itself, in inflammatory diseases of the CNS (i.e., bacterial meningitis, viral meningoencephalitis, and MS).

RESULTS

IL-18 concentrations in CSF were significantly increased in bacterial meningitis and tended toward increased levels in viral meningoencephalitis. In contrast, IL-18 was detectable only in a few patients with MS and healthy controls. Interestingly, interferon-gamma was significantly increased selectively in CSF of patients with viral meningoencephalitis.

CONCLUSION

The observation of an intrathecal release of IL-18 in patients with meningitis argues for a pathophysiologic role of this novel cytokine in immunity against invading microorganisms the CNS.