Neurological complications of herpes simplex virus type 2 infection

Herpes simplex virus type 2 (HSV-2) infection is responsible for significant neurological morbidity, perhaps more than any other virus. Seroprevalence studies suggest that as many as 45 million people in the United States have been infected with HSV-2, and the estimated incidence of new infection is 1 million annually. Substantial numbers of these persons will manifest neurological symptoms that are generally, although not always, mild and self-limited. Despite a 50% genetic homology between HSV-1 and HSV-2, there are significant differences in the clinical manifestations of these 2 viruses. We herein review the neurological complications of HSV-2 infection.

Multiple sclerosis in twins

We studied 30 sets of twins in whom one or both was suspected of having multiple sclerosis (MS). In 24 pairs, a firm clinical diagnosis was made on each twin. Among these 24 pairs, 6 of 12 monozygotic twins were concordant for clinical MS, compared with 2 of 12 dizygotic twins. Of those over the age of 50, two of three monozygotic pairs were concordant, but neither of the two dizygotic twin pairs were concordant. Because ascertainment was primarily through public announcement, this series may be biased in favor of twins concordant for MS. The individuals within monozygotic concordant twin pairs exhibited wide differences in severity and age at onset of disease; the more recently affected twin tended to have a lower cerebrospinal fluid (CSF) IgG and a higher IgM level. Although the frequency of HLA-B7 and Dw2 in this twin population was high, the HLA makeup did not differ appreciably between concordant and discordant MS twins. Furthermore, the two DZ-concordant twins were HLA-nonidentical. Unexplained neurologic signs were found in three asymptomatic twins, and a high proportion of clinically normal twins had abnormalities of CSF immunoglobulins. These latter findings suggest a high incidence of subclinical MS in this population.

Zoster myelitis: improvement with antiviral therapy in two cases

This report describes two patients with acquired immunodeficiency syndrome (AIDS) and herpes zoster myelopathy. Patient one had a T-8 myelitis that preceded the onset of T-8-distribution zoster and was followed by cervical myelopathy. Antibody to varicella zoster virus (VZV) was present in the CSF. He never received steroids or other immunosuppressive drugs, and his condition improved dramatically after treatment with intravenous acyclovir. The second patient had a rapidly progressive myelitis with paralysis of both legs. Detection of VZV DNA and antibody to VZV in his CSF led to successful treatment with famciclovir despite discontinuation of dexamethasone and earlier treatment failure with acyclovir. These cases support the idea that VZV myelopathy in the immunosuppressed host is caused by virus invasion. CSF analysis for antiviral antibody and for VZV DNA by polymerase chain reaction are helpful in establishing the diagnosis. Aggressive antiviral therapy is advised.

Oligoclonal IgG bands in cerebrospinal fluid in various neurological diseases

We studied the frequency of oligoclonal immunoglobulin G bands in the cerebrospinal fluid (CSF) of patients with various neurological diseases. We used a micromethod employing sodium dodecyl sulfate polyacrylamide gel electrophoresis that required only 50 microliters of unconcentrated CSF. Oligoclonal bands were detected in the CSF of 95% of the patients with multiple sclerosis, 90% with subacute sclerosing panencephalitis, and 100% with herpes simplex encephalitis, but less frequently in other central nervous system infections. No oligoclonal bands were detected in the CSF of patients with Parkinson, Huntington, Creutzfeldt-Jakob, or herniated disc diseases. Bands were detected in some patients with Alzheimer disease, cerebrovascular accident, idiopathic vertigo, idiopathic seizures, amyotrophic lateral sclerosis, polyneuropathy, and central nervous system glioma. Patients with other conditions infrequently had positive bands. The determination of oligoclonal bands is a useful aid in the diagnosis of multiple sclerosis, subacute sclerosing panencephalitis, and herpes simplex encephalitis. The presence of oligoclonal bands indicates an immunological response but is not diagnostic for a particular condition.

Relapsing and remitting human immunodeficiency virus-associated leukoencephalomyelopathy

We describe a 33-year-old homosexual man with a steroid-responsive, remitting and relapsing leukoencephalopathy associated with recent human immunodeficiency virus type 1 (HIV-1) seroconversion. Biopsy of a parieto-occipital lesion revealed demyelination and astrogliosis with focal necrosis. Detailed investigations demonstrated no pathogens in the brain other than HIV-1. This patient illustrates that a neurological disorder clinically indistinguishable from multiple sclerosis may be the presenting manifestation of HIV-1 infection and may occur in the absence of clinically significant immunosuppression.

Progressive multifocal leukoencephalopathy: lessons from AIDS and natalizumab

The dramatic increase in the incidence of progressive multifocal leukoencephalopathy (PML) that occurred as a consequence of the AIDS pandemic and the recent association of PML with the administration of natalizumab, a monoclonal antibody to alpha4 integrin that blocks inflammatory cell entry into the brain, has stimulated a great deal of interest in this previously obscure viral demyelinating disease. The etiology of this disorder is JC virus (JCV), a polyoma virus, observed in 80% of the population worldwide. Seroepidemiological studies indicate that infection with this virus typically occurs before the age of 20 years. No primary illness owing to JCV infection has been recognized and the means of spread from person to person remains obscure. Following infection, the virus becomes latent in bone marrow, spleen, tonsils and other tissues. Periodically the virus reactivates during which time it can be demonstrated in circulating peripheral lymphocytes. The latter is significantly more commonly observed in immunosuppressed populations than that in normal subjects. Despite the large pool of people infected with JCV, PML remains a relatively rare disease. It is seldom observed in the absence of an underlying predisposing illness, typically one that results in impaired cellular immunity. A variety of factors are likely responsible for the unique increase in frequency of PML in HIV infection relative to other underling immunosuppressive disorders. Preliminary data suggests that natalizumab appears to distinctively predispose recipients to PML relative to other infectious complications. Studies in these populations will be invaluable in understanding the mechanisms of disease pathogenesis.

Retrovirus-like particles in salivary glands, prostate and testes of AIDS patients

AIDS associated retrovirus-like particles were identified in the salivary gland, prostate and/or testicle of two AIDS patients. These findings further suggest that saliva and semen may transmit the infection to susceptible individuals.

Human T-cell lymphotropic virus type II-associated myelopathy: clinical and immunologic profiles

Human T-cell lymphotropic virus type II (HTLV-II) is endemic in several ethnic tribes and among intravenous drug users in metropolitan areas. Despite the presence of HTLV-II in these various populations, the association of HTLV-II with disease is sparse and mainly limited to isolated case reports. This study is an extension of an earlier description of an HTLV-II-infected patient with neurologic disease and presents the clinical and immunologic findings of 4 patients with HTLV-II seropositivity and spastic paraparesis. The patients are of African-American origin with 3 of the patients being of Amerindian descent. All of the patients are seronegative for the human immunodeficiency virus (HIV). The patients progressed to a nonambulatory state in less than 5 years. Magnetic resonance imaging studies obtained from 3 of the patients demonstrated white matter disease in the cerebrum and spinal cord. The cerebrospinal fluid and serum contained antibodies to HTLV-II. The presence of proviral HTLV-II was confirmed by polymerase chain reaction analysis of peripheral blood lymphocytes (PBLs). A spinal cord biopsy from 1 patient demonstrated HTLV RNA within a lesion. Immunologic studies on 2 patients demonstrated that spontaneous lymphoproliferation of PBLs was present but decreased relative to HTLV-I-infected patients. The clinical and immunologic findings from these HTLV-II-infected patient resemble those found in HTLV-I-associated myelopathy/tropical spastic paraparesis.

Oligoclonal banding in the cerebrospinal fluid of patients with postencephalitic Parkinsonism

Two recent sporadic cases of progressive Parkinsonism after encephalitis are described. Both patients had two oligoclonal protein bands in their CSF. These bands were not present in patients with idiopathic Parkinson's disease and might, therefore, be useful for diagnostic purposes, particularly when the history of encephalitis is uncertain.