Isolation of HTLV-III from cerebrospinal fluid and neural tissues of patients with neurologic syndromes related to the acquired immunodeficiency syndrome

Otoneurological abnormalities in asymptomatic HIV-seropositive patients

Twenty-four male patients, all homosexual except one, with asymptomatic HIV-infection were studied. The patients had no signs of opportunistic CNS-infections but 6 had been treated for syphilis. The patients were tested with auditory brainstem response (ABR) audiometry and with oculomotor tests (saccades and smooth pursuit eye movements). The ABR-recordings were pathological in 38% of the cases and the oculomotor tests in 50% of the cases. Abnormality of either one or of both methods were seen in 67% of the patients tested. The duration of the HIV-infection had no influence on the test results. The abnormal otoneurological tests indicate that occult CNS-dysfunction is a frequent finding in asymptomatic HIV-positive patients.

CSF and serum beta-2-microglobulin in HIV infection related to neurological dysfunction

Elevated (greater than 2.2 mg/l) CSF beta-2-microglobulin (beta 2m) level was found in 9 of 16 neurologically symptomatic patients but in only 4 of 21 who were neurologically symptom-free (P less than 0.01). Serum beta 2m concentration was elevated (greater than 2.5 mg/l) in 12 of 16 neurologically symptomatic patients but in only 8 of 21 symptom-free patients (P less than 0.01). When the CSF and serum beta 2m levels were related to various stages of HIV infection, the highest mean values for both CSF and serum were found in patients with acquired immunodeficiency syndrome (AIDS), followed by lower values in AIDS-related complex (ARC), lymphadenopathy syndrome (LAS), and asymptomatic seropositive individuals (ASX), in decreasing order of preference. Our results suggest that elevated beta 2m in CSF and serum is related to the stage of general HIV infection and that elevated CSF beta 2m in the presence of intact BBB may be useful in evaluating CNS involvement in HIV-infected patients.

Immunoglobulins and complement components in 37 patients infected by HIV-1 virus: comparison of general (systemic) and intrathecal immunity

Intrathecal (IT) immunity was assessed by simultaneous analysis of paired cerebrospinal fluid (CSF) and sera of 37 patients infected by human immunodeficiency virus-1 (HIV-1). Only 8 of these 37 patients had no neurological or neuropsychiatric symptoms. There were 3 prominent abnormalities observed: (1) IT IgA production occurred in 15 patients, IT IgM production in 14 patients, and IT IgG production in 34 patients. (2) IT Anti-HIV-1 antibody specific activity (ASA) was higher than in serum in 33 of the 37 patients indicating that IT synthesis of antibody specific for HIV-1 occurs even in asymptomatic patients; IT anti-HIV-1 antibody synthesis was not correlated with clinical severity or neurological involvement. IT anti-herpes simplex ASA was also higher than serum ASA in 6 patients indicating a possible associated herpes simplex virus infection. (3) IT production of the complement component C4 was found frequently and was highly correlated with increased serum C4. IT C3 levels were decreased in 21 of 37 patients indicating that complement activation is a frequent accompaniment of the IT immune response in HIV-1-positive patients. These results indicate a unique and localized IT immune response which is different from the pattern observed in the systemic immune compartment in HIV-1-seropositive individuals and from the pattern common to the other CNS infectious diseases.

Central nervous system AIDS

The retrovirus that causes the acquired immunodeficiency syndrome (AIDS) has two targets: the immune system and the nervous system. Central nervous system (CNS) manifestations of AIDS are protean. This review describes the opportunistic infections and malignancies that affect the nervous system in AIDS, and discusses the syndromes resulting from primary infection of the CNS by the AIDS virus. Possible mechanisms of CNS injury are cited as well as potential predictors of neurologic expression of AIDS.

Estimation of the lipophilicity of anti-HIV nucleoside analogues by determination of the partition coefficient and retention time on a Lichrospher 60 RP-8 HPLC column

There is a close linear correlation between the log partition coefficient (Pa) of a series of 2'-deoxyriboside (dR), 2',3'-didehydro-3'-dideoxyriboside (ddeR), 2',3'-dideoxyriboside (ddR), 3'-fluoro-2',3'-dideoxyriboside (FddR) and 3'-azido-2',3'-dideoxyriboside (AzddR) derivatives of uracil, cytosine, thymine, guanine, adenine and 2,6-diaminopurine and their retention times (Rt) on a Lichrospher 60 RP-8 HPLC column (correlation coefficient r greater than 0.970). Within each class of compounds the following order of increasing lipophilicity was noted: dR less than ddeR less than ddR less than FddR less than AzddR. A straight-forward structure-lipophilicity relationship for both base and sugar modified purine and pyrimidine 2',3'-dideoxynucleosides could be delineated.

Biological and molecular characterization of human immunodeficiency virus (HIV-1BR) from the brain of a patient with progressive dementia

HIV-1BR was isolated from the autopsied brain tissue of a 57-year-old man who died of progressive dementing illness. This virus was shown to be HIV-1 by hybridization to HIV-specific DNA probes. The expression of viral proteins as tested by radioimmunoprecipitation assay revealed the presence of HIV-1-specific proteins. HIV-1BR replicated in cultures of CD4+ T-lymphoid cells and induced cytopathic effects in these cells. HIV-1BR also replicated in monocytoid cell lines. The genetic nature of this isolate was determined by molecular cloning and sequencing of the 3'-half of the genome. DNA sequence information established that HIV-1BR is a unique HIV-1 isolate. A stretch of approximately 30 bases in the nef gene of HIV-1BR was found duplicated when compared with the other sequenced HIV-1 genomes. The functional significance of this duplication remains to be determined.

Neuropathology of the acquired immune deficiency syndrome (AIDS): a report of 135 consecutive autopsy cases from Switzerland

Neuropathological changes were studied in a consecutive autopsy series of 135 cases, comprising 73% of all patients who died of AIDS in Switzerland between April 1981 and December 1987. Central nervous system involvement was found in 119 patients (88%), 19 of which had multiple concomitant intracerebral lesions. Among the non-viral opportunistic infections, encephalitis due to Toxoplasma gondii was most frequent and occurred in 35 patients (26%), followed by central nervous system infection with Cryptococcus neoformans, which was found in five patients (4%). Cytomegalovirus (CMV) encephalitis was present in 14 patients (10%). Disseminated microglial nodules without morphological or immunocytochemical evidence of CMV was encountered in 18 patients (13%). However, in all but two of these patients there was evidence of extracerebral CMV infection, suggesting that CMV was responsible for these nodular encephalitides. Nine patients (7%) had progressive multifocal leukoencephalopathy (PML); in five of these, demyelination was associated with extensive tissue destruction and cyst formation. HIV-associated encephalopathy was observed in 21 patients (16%) and showed two characteristic morphological patterns: progressive diffuse leukoencephalopathy (PDL) and multifocal giant cell encephalitis (MGCE). PDL was observed in 13 cases and characterized by diffuse pallor and gliosis of the cerebral and cerebellar white matter with scattered multinucleated giant cells, but without significant inflammatory response. MGCE was found in eight patients and characterized by clusters of numerous multinucleated giant cells, rod cells, macrophages, lymphocytic infiltrates and occasional necroses. In our view, PDL and MGCE represent the two opposite variants of HIV-induced encephalopathies, with overlapping intermediate manifestations.

Human immunodeficiency virus (HIV)-induced disease of the central nervous system: pathology and implications for pathogenesis

Significant contributions from many different groups during the last 2 or 3 years have characterized relatively uniform neuropathological changes of the CNS in AIDS patients. They feature human immunodeficiency virus (HIV)-induced multinucleated giant cells as a histopathological hallmark and HIV demonstrable by electron microscopy, immunocytochemistry, and in situ hybridization. Unfortunately, a varying and confusing terminology is used to designate these changes which have been reported in surprisingly different incidences. Focal lesions have a microgranulomatous appearance and were designated as multifocal giant cell encephalitis or subacute encephalitis, which may be confused with the nodular encephalitis caused by cytomegalovirus. For some authors, the latter designation also covers characteristic diffuse white matter changes which have been termed progressive diffuse leukoencephalopathy by others, and which may overlap with focal lesions. Pathological features of these HIV-induced syndromes and other data do not support a major cytopathic effect of HIV on neural cells; rather, they suggest secondary pathogenetic events involving the predominant cell type in the lesion, the monocyte/macrophage/microglia. However, low-level, latent, and persisting HIV infections of neural cells cannot be excluded at present; the CNS may then serve as an early infected virus reservoir. A detailed correlation of clinical symptoms and stage of the infection to neuropathological changes is currently lacking but urgently needed. The presence of the HIV-receptor (CD4) molecule on brain cells is controversial; similarly, a putative cross-reaction of HIV proteins with trophic substances and transmitters needs to be substantiated.

AIDS in Africa: emerging trends

This paper reviews the literature on AIDS in Africa. By 29 February, 1988, 9760 cases of AIDS had been reported in Africa. This review addresses the currently accepted belief in the African origin of AIDS, the distribution (cluster) of AIDS in Africa, identified modes of transmission, and changing sexual and drug use behaviors in Africa. There is no conclusive evidence to show that the AIDS virus originated in Africa. Even if the progenitor virus had a habitat in central Africa, certain high-risk sexual behaviors which were introduced in the 60s and 70s may have initiated the infectious process. The distribution pattern does not suggest a transcontinental spread; rather, it suggests a contigual and transatlantic spread. The primary mode of transmission is heterosexual activity. This paper raises a number of questions relating to heterosexual behaviors. Other issues addressed include drug use behavior, homosexuality, and high-risk sexual activities of Africans and foreigners in Africa. Other modes of transmission are transfusion of contaminated blood and blood products, use of nonsterile needles, and perinatal transmission. It is not likely that traditional (folk) medicine will contribute to the spread of AIDS. Traditional doctors use fresh razor blades for cuts and not hollow instruments such as needles. The impact of the political and socioeconomic climate in most of Africa during the 60s and early 70s is evaluated. Finally, we make suggestions for future direction, which include confirmatory testing of HIV Positive samples, conducting clinical epidemiology and social science-based research, and developing innovative education programs that are culturally relevant.

Neurodevelopmental delay and focal seizures as presenting symptoms of human immunodeficiency virus I infection

Three children presenting with neurological symptoms were subsequently diagnosed as being infected with the human immunodeficiency virus I (HIV). All children showed normal development for about 12-18 months of age but later developed psychomotor and developmental regression. One child presented with generalised hypotonia, another with focal seizures, and the third with spastic quadriplegia. Two of the children showed areas of abnormal brain density on computed tomography and in one case there was calcification of the basal ganglia. In two of the children cerebrospinal fluid contained reduced amounts of total folate and elevated concentrations of neopterin. The possibility of a link between the deranged folate metabolism and the neurological symptoms in HIV infection is discussed.

Vacuolar myelopathy with multinucleated giant cells in the acquired immune deficiency syndrome (AIDS). Light and electron microscopic distribution of human immunodeficiency virus (HIV) antigens

Vacuolar myelopathy (VM) is a frequent neurological complication of the acquired immune deficiency syndrome (AIDS). A suspected connection between VM and human immunodeficiency virus (HIV) has been based only on HIV isolation from affected spinal cord tissue. We report here an AIDS patient dying after 14 months of progressive dementia, including 3 months of spinal signs and symptoms. At autopsy, the brain revealed moderate diffuse damage of the white matter compatible with HIV-induced progressive diffuse leukoencephalopathy. The spinal cord showed VM mainly in the lateral and the posterior columns. Mono- and multinucleated macrophages were localized within intramyelinic and periaxonal vacuoles. Light and electron microscopic immunocytochemistry revealed the presence of HIV antigens restricted to mono- and multinucleated macrophages within the spongy lesions. Productive HIV infection is documented for the first time within VM lesions of this case. Therefore, VM should be included among HIV-induced lesions of the central nervous system. The intimate relation of infected macrophages to vacuolar myelinopathy could suggest secretion of a myelinotoxic factor by macrophages productively infected by HIV. Immune electron microscopy appears as promising tool to detect HIV in tissue even when the density of virus may be low.

Cell association of HIV in AIDS-related encephalopathy and dementia

The presence of HIV gag and env proteins (HIV Ag) and virus replicating cells was studied by immunohistochemistry and in situ hybridization, respectively, in brain specimens from five HIV infected patients. HIV antigens were detected in 3 of 5 brains in micronodular areas characterized by increased cellularity and the presence of multinuclear giant cells. By double immunostaining, HIV Ag positive cells were shown to express markers common to macrophages and microglia i.e. Leu M5+, My4+, HLA-Dr+, RCA-1+, and to a lesser extent CD4+ (Leu3+). Another macrophage specific marker, KiM6, was found only on HIV+ cells in HIV infected specimens and not in uninfected, control brains. Medium-sized, virus replicating cells were found exclusively in micronodular areas, but in much smaller quantities than HIV Ag+ cells. Our observations provide further evidence to support the hypothesis that macrophages play an important role in CNS infection by HIV and additionally support the concept that reactive microglial originate from activated macrophages infiltrating the brain. Both direct effects of viral components and cell mediated reactions can be implicated from our findings as mechanisms involved in the pathogenesis of the CNS lesions.

EEG discharges in WR 1-5 HIV-seropositive hemophiliacs

Human immunodeficiency virus (HIV)-seropositive patients show involvement of the central and/or peripheral nervous system. We present here the results of electroencephalographic (EEG) findings in stage WR 1-5 HIV-seropositive hemophiliacs from a total of 184 who attended our clinic prior to October 1987.

Immunity assessment in the early stages of amyotrophic lateral sclerosis: a study of virus antibodies and lymphocyte subsets

Serum and CSF from 32 patients with idiopathic ALS, 30 age-matched controls and 30 MS patients were investigated regarding immunoglobulin concentration and virus-specific antibodies, the lymphocytes in the peripheral blood and lymphocyte subsets were also investigated. ALS patients' results were compared with findings in MS and controls. The ALS patients had significantly higher IgG concentration in serum than the controls, marked lymphopenia, reduction of CD2, CD8 and Leu 7 positive cells and increase of the CD4/CD8 ratio and of SIg-positive lymphocytes. Compared with the MS patients, the ALS patients showed similarity in T-subset distribution with a lower standard deviation. No HTLV-I and HIV antibodies were found in any group and no significant differences in antibody distribution to Toxoplasma G, herpes simplex, cytomegalovirus, measles and mumps viruses were evident. All ALS patients were investigated at an early disease stage, therefore, our findings seem to support the conclusion that the immune alterations are related to the mechanisms of the disease and not to complications of its evolution.

Bone marrow derived cells express human T-cell lymphotropic virus type I (HTLV-I)-related antigens in patients with multiple sclerosis

Mononuclear cells in peripheral blood (PB) and cerebrospinal fluid (CSF) of seven patients and lymph nodes of three patients with clinically definite multiple sclerosis (MS) expressed antigens that reacted with monoclonal antibodies (MoAb) specific for HTLV-I p19 and p24 gag proteins. The labelled cells were visualized with immunoperoxidase staining and indirect immunofluorescence and identified at the ultrastructural level with immunogold technique. The frequency of these cells was low, ranging from 0.1% to less than 0.01% in blood. In CSF it was approximately 10 times lower. Cells reacting with anti-p19 Ab were found in all MS samples, whereas cells reacting with anti-p24 Ab were found in 3 out of 6 blood samples and in 3 out of 7 CSF samples. All lymph nodes (3/3) obtained from MS patients contained cells that reacted with anti-HTLV-I. p19 and p24 Ab. Cells reacting with the same AB were detected in blood of one out of 12 healthy controls. Stained cells were irregular, distinctly larger than lymphocytes, and had abundant cytoplasm, suggesting that they may be monocytes/macrophages. Immunogold particles were located in vacuole-like structures in the cytoplasm. The presence in MS patients of cells that react with HTLV-I Ab indicates that a human retroviral genome is being expressed, and suggests that a virus may be present. Our data support a role for a human retrovirus in multiple sclerosis.

Neurological features in AIDS patients: studies on cerebrospinal fluid

The relationship between cerebrospinal fluid (CSF) markers of HIV infection and the spectrum of neurological manifestations were studied in 15 AIDS patients (13 with and 2 without confirmed neurological disorders). We demonstrated the presence of intrathecally synthesized anti-HIV antibodies. Antibodies to HIV envelope proteins were present in all patients but those to HIV core proteins in 9/13 cases only. HIV antigen and HIV p24 antigen were present in 6/14 and 4/12 cases respectively. HIV was not isolated from 6 samples of CSF. We have demonstrated that CSF markers of HIV infection were present in all AIDS patients, with or without neurological manifestations. Moreover HIV p24 antigen seems to be a very reliable marker of HIV infection.

Flow cytometric quantitation of T cell phenotypes in cerebrospinal fluid and peripheral blood of homosexual men with and without antibodies to human immunodeficiency virus, type I

Two-color flow cytometry was used to analyze T cell subsets (total (CD3), helper-inducer (CD4), and suppressor-cytotoxic (CD8] in paired specimens of cerebrospinal fluid (CSF) and peripheral blood of 66 homosexual men, including 62 with antibodies to human immunodeficiency virus, type 1 (HIV-1). With the exception of one traumatic specimen, all of the CSF specimens, 52 of which had less than or equal to 5 lymphocytes/mm3, were evaluated fully, with the number of lymphocytes counted for each antibody ranging from 200 to 2933 (mean = 1129). Proportions of CD3, CD4, and CD8 lymphocytes in CSF were very highly correlated with the proportions of these cells in the peripheral blood (r = 0.87, 0.96, and 0.94, respectively), as was the CD4/CD8 ratio (r = 0.98). These strong correlations were present in each of seven subgroups of study subjects defined on the basis of detailed neurologic examination, neuropsychological testing, and the presence or absence of antibodies to HIV-1. In the population studied, T cell phenotypes in CSF as analyzed by two-color flow cytometry were largely determined by the corresponding proportions in the peripheral blood.

Detection of human immunodeficiency virus antigen in vitreous humor

The vitreous humor from 11 patients with acquired immunodeficiency syndrome was obtained at postmortem examination and tested for human immunodeficiency virus antigen and antibody by using the Abbott enzyme-linked immunosorbent assay procedures. Five patients had detectable antigen, supporting the recent observation that the virus may directly infect the retina.

Otologic disease in patients with acquired immunodeficiency syndrome

A 5-year retrospective study evaluating otologic disease in patients with acquired immunodeficiency syndrome (AIDS) was conducted at the New York University Medical Center-Bellevue Hospital Center. Twenty-six patients with documented otologic disease who met the Centers for Disease Control criteria for AIDS were identified and their charts were analyzed according to presenting complaints, physical examination, diagnostic modalities, pathologic condition, management, and outcome. A marked diversity of otologic diseases of varying severity was noted. The majority of patients complained of hearing loss and otalgia during their hospitalization for treatment of AIDS-related opportunistic infections. The most frequent diagnoses were otitis externa, acute otitis media, and otitis media with effusion. Sensorineural hearing loss frequently appeared to be related to ototoxic medications and neurologic infections.

Psychosis associated with HIV infection

Five cases of psychiatric illness, presenting as functional psychosis, occurring in male homosexuals with human immunodeficiency virus (HIV) infection are described and compared with similar cases in the literature. The association between psychosis and infection with HIV is discussed with particular emphasis on the significance of functional versus organic presentation.

Brainstem ocular motility defects and AIDS

Ocular motility manifestations of focal brainstem dysfunction were the initial clinical features in three patients with human immunodeficiency virus (HIV) infection. These included conjugate gaze palsy with ipsilateral facial paresis, bilateral abducens palsy and a gaze paresis, and homolateral internuclear ophthalmoplegia and abducens nerve paresis. Two patients had focal brainstem lesions as evidenced on neuroimaging. The third showed concurrent infection with Treponema pallidum.

Increasing intrathecal lymphocytosis and immunoglobulin G production in neurologically asymptomatic HIV-1 infection

Cerebrospinal fluid from 34 human immunodeficiency virus (HIV-1) seropositive patients, only four of whom had HIV-related neurological symptoms, was examined by cytology, protein quantification, isoelectric focusing and specific serological tests. CSF lymphocytosis and evidence of intrathecal IgG production, found in 21 and 20 respectively of the 34 patients, correlated significantly with the duration of the infection. Increasing IgG index was found in two patients with repeated CSF examinations during greater than 7 years. Intrathecal HIV antibodies were detected on Western blot in 32/34 patients. HIV antigen test positive in 5/34 sera was negative in all 34 CSF samples. Intrathecal B cell activation seems to increase during the early HIV infection.

Human immunodeficiency virus infection of the brain. II. Detection of intrathecally synthesized antibodies by enzyme linked immunosorbent assay and imprint immunofixation

Sera and CSF from 29 patients in early and late stages of HIV infection were analysed for intrathecal antibody production. Elevated CSF-IgG indices indicating intrathecal IgG synthesis were demonstrated in 9 patients while 4 of 18 patients tested had oligoclonal IgG bands in the CSF. Analysis of HIV-specific antibodies by enzyme-linked immunosorbent assay (whole antigen and site-directed ELISA) and calculation of "antibody indices" (CSF/serum antibody quotient divided by CSF/serum albumin quotient) indicated intrathecal HIV antibody synthesis in 19 patients. Analysis of serum and CSF antibodies by an imprint immunofixation (IIF) method showed intrathecal synthesis of predominantly polyclonal HIV-IgG antibodies in 11 of 13 patients examined. IIF analysis of antibodies to six other infectious agents showed no intrathecal antibody production except in one patient who had minor fractions of intrathecally synthesized IgG antibodies to varicella zoster virus. The present results demonstrate that an intrathecal HIV-specific antibody response may be present in both early and late stages of HIV infection, and indicates that HIV may reach the brain at an early stage of infection.

Isolation frequency of human immunodeficiency virus from cerebrospinal fluid and blood of patients with varying severity of HIV infection

Isolation of the human immunodeficiency virus (HIV) has been attempted from the cerebrospinal fluid (CSF) of 63 subjects at different stages of HIV infection, including asymptomatic carriers and patients with or without neurologic or psychiatric complications. In addition blood was collected from 40 of these subjects for virus isolation. HIV could be isolated from the CSF at all clinical stages with an overall frequency of 40%. In contrast, the frequency of HIV isolation from the blood was lower (32%) at the early stages of infection than in patients with severe disease (77%). HIV isolation from the CSF was more frequently positive in patients with neurologic or psychiatric complications than in patients showing no such disturbances (48 and 32%, respectively).

Recovery of human immunodeficiency virus from ocular tissues in patients with acquired immune deficiency syndrome

Human immunodeficiency virus (HIV) was recovered from multiple ocular tissues in three patients with acquired immune deficiency syndrome (AIDS). Consistently found in the retina, HIV was also detected in the conjunctiva, cornea, and iris. In two cases, HIV was detectable despite treatment with oral zidovudine. All three patients had bilateral cytomegalovirus (CMV) retinitis managed by intravitreal injection of ganciclovir. Culture of the retina for CMV was negative in all three cases. The finding of HIV in multiple ocular tissues is consistent with the neurotropic nature of the virus, and may explain some of the common ocular manifestations of AIDS such as AIDS retinopathy. Infection with HIV may predispose the retina to other opportunistic infections and may explain the high incidence of CMV retinitis in AIDS patients. This is the first report of HIV isolation from tissue within the eye.

Brain atrophy with intracranial calcification following congenital HIV infection

An 18-month-old girl with AIDS related complex following congenital HIV infection suffered since the first days of life from severe neurological disturbances. The extensive congenital brain atrophy and the diffuse intracranial calcification which were found were strongly reminiscent of intrauterine infection. Since the agents usually responsible for congenital infections were excluded an HIV embryopathy appears likely.

Efficient isolation of HIV from plasma during different stages of HIV infection

Attempts to isolate human immunodeficiency virus (HIV) from blood plasma using inoculation of pellets from ultracentrifuged samples into cultures of peripheral blood mononuclear cells (PBMC) resulted in a high overall recovery rate (75%) of the virus from 76 patients in various stages of HIV infection. The recovery rate was dependent on the stage of infection; in patients with acquired immunodeficiency syndrome (AIDS) it was 100%, in AIDS-related complex (ARC) 86%, in persistent generalized lymphadenopathy (PGL) 64%, and in asymptomatic patients 54%. The HIV isolation rates compared favorably with those obtained after cocultivation of patient and target PBMC (overall recovery rate 67%). HIV was isolated from plasma but not from PBMC in 8 cases, whereas the reverse was true in 3 of 71 simultaneously tested cases. Isolation from plasma was found to be superior to detection of serum p24 antigen for the demonstration of HIV (positivity rates 75% and 30%, respectively). The time to appearance of p24 antigen in cultures inoculated with HIV-containing plasma samples was inversely related to the presence of detectable p24 antigen in serum. There was a significantly shorter time to culture positivity of plasma samples from AIDS and ARC patients than from PGL and asymptomatic patients. These results suggested that there is a progressive increase in the concentrations of infectious HIV in plasma from the asymptomatic to the AIDS stage. HIV isolation from plasma samples is a reliable means of demonstrating HIV viremia and has obvious advantages over the more commonly used cocultivation procedures. The frequent occurrence of cell-free, infectious HIV in plasma suggests that the majority of HIV-infected patients have a relative lack of functional neutralizing antibodies against the virus, at least during the late stages of disease.

Neuropathology of acquired immunodeficiency syndrome

The nervous system is involved in the acquired immunodeficiency syndrome (AIDS) by infections and infestations, by neoplasms, and by several diseases of uncertain pathogenesis. The most common pathological abnormalities are the changes associated with the HIV agent itself, the 'HIV subacute encephalitis'; the most specific change is demyelination with multinucleate giant cells. Cytomegalovirus (CMV) is the most common secondary virus, but progressive multifocal leucoencephalopathy (PML) is more frequently seen at biopsy. Toxoplasmosis is the most common cause of abscess formation, but fungal infections, especially by cryptococcus, are more often the cause of meningitis. Mycobacterial infections and other opportunistic organisms are relatively rarely seen in the CNS. A vacuolar myelopathy of unknown pathogenesis is seen in AIDS; it involves the dorsal and lateral columns and the thoracic spinal cord most prominently. Endarteritis of unknown cause with resultant infarction is seen in children. Primary CNS lymphoma accounts for a major percentage of the lymphomas seen in AIDS; they are high grade tumours, are most often multiple, and are of B-cell origin. Metastatic Kaposi's sarcoma is very rare. Several peripheral neuropathies occur in AIDS, and recently a myopathy with small rod bodies has been reported.

Anti-HIV antibodies in the CSF of AIDS patients: a serological and immunoblotting study

CSF and serum samples from 16 AIDS patients were tested for the presence of anti-HIV antibodies either by classical serological methods or by an immunoblot technique based on agarose gel isoelectric focusing and transfer of the specific IgG antibodies onto HIV antigens-loaded nitrocellulose sheets. This method enabled the demonstration of an intrathecal synthesis of anti-HIV oligoclonal IgG antibodies, often superimposed on diffuse polyclonal production, in 14 patients. The two negative cases were devoid of neurological signs or symptoms. However, two patients classified in stage II of the disease (asymptomatic infection) displayed an intrathecal synthesis of anti-HIV antibodies.

Impairment of cranio-facial nerves due to AIDS. Report of 2 cases

2 cases of disorders of craniofacial nerves resulting from progressive multifocal leucoencephalopathy are described. Clinical symptoms occurred as facial paralysis, hypaesthesia, hemianopsia and deafness. In both patients, the impairment of the central nervous system (CNS) preceded indicative AIDS symptoms. Both patients died about 3 months after the first CNS symptoms had been diagnosed. Clinical and neurohistopathological findings as well as differential diagnoses are discussed.