The absence of JC virus antigens in Indian children with medulloblastomas.

BACKGROUND: The human polyoma virus, also known as the JC virus (JCV), replicates predominantly in the oligodendrocytes, the myelin producing cells in the central nervous system and results in the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML) especially in immunosuppressed patients with AIDS. Several investigators have also documented the presence of the viral genome and early and late antigens in a variety of brain tumors particularly in medulloblastomas, gliomas and ependymomas. Reports also indicate the presence of JCV in patients with colon cancer. The T antigen of JCV has been postulated to have oncogenic potential as substantiated by animal experiments. Although JCV infects 80% of the population, there are scant epidemiological studies regarding JCV from India. There are also reports of the low prevalence of PML in patients with AIDS from India and Africa. AIM: This study was undertaken to investigate if Indian children with medulloblastomas also show evidence of JCV. METHODS: Twenty-two consecutive cases of medulloblastomas were investigated for the presence of T antigen and agnoprotein of JCV in biopsy specimens by immunohistochemistry. Antibodies to the agnoprotein antigen raised in rabbits and a monoclonal antibody against SV40 T antigen raised in mice that cross-reacts with JCV T antigen were used. RESULTS: Out of 22 patients, 4 had desmoplastic tumors while the rest had classical tumors. All children were below the age of 10. Results indicate that while PML tissues showed consistent immunostaining both with antibody to T antigen and agnoprotein antibody, none of the tumors showed any positive staining for JC viral antigens. CONCLUSION: JCV antigens could not be detected by immunohistochemistry in the tumor tissues of Indian children with medulloblastomas.

HIV3B AND HIV Ada-M CAN INFECT CULTURED HUMAN DORSAL ROOT GANGLION NEURONS / 神经解剖学杂志

To investigate whether HIV3B and HIV Ada-M can infect cultured human dorsal root ganglion (DRG) neurons, organotypic and dissociated human fetal DRG cell culture models were established. On the 14th day, organotypic cultured DRG explants were exposed to HIV3B or HIV Ada-M for another 14 days. Outgrowth and morphology of neurites were observed with phase contrast microscope at different time of cultured age. On the 3rd day, dissociated cultured DRG cells were exposed to HIV3B or HIV Ada-M for another 3 days. After that, dissociated DRG cells were processed for microtubule-associated protein 2 (MAP2) labeling and observed with fluorescent microscopy. DRG explants on the 28th day and dissociated DRG cells on the 6th day, the samples were processed for electronic microscopic observation. Both organotypic and dissociated DRG cultures were cultured continuously in culture media as controls. Immature HIV-like particles were found in organotypic cultured DRG neurons. Many HIV-like particles were found in dissociated cultured DRG neurons. HIV infection could not cause morphological and ultrastruc( )l alterations on both organotypic and dissociated cultured DRG neurons. These discoveries will be valuable for studies on pathogenic (mee)hanisms of HIV infection and/or HIV associated peripheral neuropathies.

Neuropathology of HIV/AIDS with an overview of the Indian scene.

Neurological manifestations of HIV infection and AIDS are being recognized with a frequency that parallels the increasing number of AIDS cases. Next to sub-Saharan Africa, India has the second largest burden of HIV related pathology, essentially caused by HIV-1 clade C in both the geographic locales, in contrast to USA and Europe. But the true prevalence of HIV related neuroinfections and pathology is not available due to inadequate medical facilities, social stigma and ignorance that lead to underdiagnosis. Neurotuberculosis, followed by cryptococcosis and toxoplasmosis in various combinations are the major neuropathologies reflecting the endemicity and manifesting clinically by reactivation of latent infection. Discordance in the clinical prevalence of various infections, when compared to pathological studies highlight similarities in clinical, radiological modalities of diagnosis and inherent problems in establishing definitive diagnosis. Viral infections appear to be relatively rare. Inspite of heavy burden of HIV/AIDS, HIV associated neoplasia is infrequent, including primary CNS lymphomas. HIV encephalitis and HIV associated dementia are considered infrequent, though systematic studies have just been initiated in various centres. Peripheral neuropathy characteristically manifests with vasculitic neuropathy while diffuse infiltrative lymphocytosis syndrome (DILS) involving nerves has not been reported from India. Spinal cord pathology including vacuolar myelopathy is rare, even in asymptomatic cases. Till now the AIDS cases in India were drug naive but a new cohort of cases following initiation of HAART therapy as a national policy is soon emerging, altering the biology and evolution of HIV/AIDS in India. Lacunae in the epidemiology, diagnosis and study of biology of HIV/AIDS are outlined for future research.