Neurological complications of acquired immune deficiency syndrome: analysis of 50 patients

Pediatric AIDS: comparative cranial MRI and CT scans

Fourteen consecutive children (age range: 4 months to 11 years; median: 4 years) with acquired immunodeficiency syndrome (AIDS) were studied prospectively with cranial magnetic resonance imaging (MRI) and unenhanced computed tomography (CT). In 4 children, human immunodeficiency virus infection was transfusion-related, while in 10, transplacental transmission occurred. Twelve children had abnormal neurologic examinations; of these, 10 had developmental delay and 2 were normal by developmental history and neurologic examination. Standardized neuropsychologic tests were given to all children; 5 were in the normal range and 9 demonstrated significant delays in verbal or motor/perceptual development. All children with abnormal neuropsychologic results were developmentally delayed; however, in 2 infants with normal neuropsychologic assessments, developmental delay and abnormal neurologic examinations were documented. Brain parenchymal volume loss (8 patients) and cervical lymphatic hypertrophy (4 patients) were demonstrated equally well by MRI and CT. CT alone demonstrated striatal-thalamic calcification (1 patient), whereas MRI alone demonstrated delayed myelination (1 patient). The extent of focal white matter lesions in 1 patient was demonstrated better by MRI than by CT. No intracranial mass lesions were demonstrated; however, significant correlations were found between peripheral volume loss imaged by either MRI or CT and both verbal and performance scores. In our small series, MRI offered no apparent advantage over CT in evaluating children with AIDS. We suggest that CT alone is sufficiently sensitive in evaluating pediatric AIDS-related brain abnormalities.

[Non tumor intracranial expansive processes: clinico-topographical correlation]

Presentation of clinical-tomographic correlation in 111 cases of non tumoral intracranial expansive processes seen between 1984-1988 in the Hospital Cayetano Heredia (Lima, Peru). Emphasis is given fundamentally to: (1) the importance of establishing the organicity of partial and late epilepsy; (2) the high incidence rate of inflammatory infectious processes with CNS compromise in underdeveloping countries; (3) the necessity of making public the importance of two parasitic diseases in the differential diagnosis of non tumoral intracranial expansive processes: free living amebiasis, and toxoplasmosis (especially in association with AIDS).

Autonomic neuropathy is common in human immunodeficiency virus infection

We prospectively evaluated autonomic nervous system function in 17 consecutive ambulant patients with HIV infection [mean age (S.D.) 34.5 (5.5) years] and 17 controls matched for sex and age [31.2 (7.4) years]. A questionnaire was administered, and neurological examination and standard bedside autonomic function tests were performed. Eleven of 17 HIV-infected individuals (64.7%) had symptoms suggestive of autonomic dysfunction, particularly urogenital problems. Thirteen of 17 (76.5%) had autonomic neuropathy (one or more abnormal tests), including nine of 11 symptomatic individuals. Only two controls had any autonomic symptoms, and all had normal tests. Autonomic dysfunction is common in those with HIV infection and AIDS.

Prominent cortical atrophy with neuronal loss as correlate of human immunodeficiency virus encephalopathy

A 25-year-old homosexual AIDS patient presented with progressive cognitive, motor and behavioral disturbances consistent with HIV encephalopathy. CT scans demonstrated progressive diffuse brain atrophy. Neuropathology showed predominant cortical changes including severe neuronal loss corroborated by morphometry. Only minimal changes were found in the white matter and basal ganglia. Immunocytochemistry for HIV stained occasional microglial cells more markedly in the cerebral cortex. This suggests that HIV infection of the brain may cause predominant cortical nerve cell loss, and that HIV encephalopathy is not necessarily due to white matter lesions.

Inhibition of entry of HIV-1 in neural cell lines by antibodies against galactosyl ceramide

Although the CD4 molecule is the principal cellular receptor for the human immunodeficiency virus (HIV), several CD4-negative cell lines are susceptible to infection with one or more HIV strains. These findings indicate that there are alternate modes of viral entry, perhaps involving one or more receptor molecules. Antibodies against galactosyl ceramide (galactocerebroside, or GalC) inhibited viral internalization and infection in two CD4-negative cell lines derived from the nervous system: U373-MG and SK-N-MC. Furthermore, recombinant HIV surface glycoprotein gp120 bound to GalC but not to other glycolipids. These results suggest a role for GalC or a highly related molecule in HIV entry into neural cells.

Human immunodeficiency virus-1 infection of the nervous system: an autopsy study of 268 adult, pediatric, and fetal brains

The central nervous system (CNS) of 221 adults and 31 infants or children with the acquired immunodeficiency syndrome (AIDS) was examined with immunocytochemistry for infectious agents and for human immunodeficiency virus-1 (HIV-1) antigen (gp41). Since the major risk factor in this population was intravenous drug abuse, there were more female and pediatric patients than in other neuropathology autopsy series. Although children had a different spectrum of pathologic changes, including less frequent opportunistic infections, women did not differ from men in terms of types or incidence of opportunistic infections, vascular disease, neoplasia, and subacute AIDS encephalitis (SAE). Subacute AIDS encephalitis was detected in 26% of adult and 48% of pediatric brains. Immunocytochemical analysis of 100 adult and 20 pediatric brains revealed gp41 immunoreactivity in 78% and 40%, respectively. Virtually all adult brains with SAE had gp41 immunoreactivity in macrophages and microglia. Even brains with no significant pathology had frequent gp41 immunoreactivity, especially in the basal ganglia. In pediatric brains, including cases with SAE, gp41 immunoreactivity was less abundant, suggesting the possibility of latent infection or viral clearance. Spinal cords with vacuolar myelopathy or corticospinal tract degeneration had only rare gp41-positive cells. Brains from 16 aborted fetuses from HIV-1-seropositive women were all negative for gp41 immunoreactivity, but 12 brains were positive for HIV-1 by the polymerase chain reaction. These results may indicate that HIV-1 infection in fetal brains is below the limits of detection of immunocytochemistry. The differences noted between adults and children suggest that adults more often have productive CNS HIV-1 infection.

Trends and survival for AIDS patients presenting with indicative neurologic diseases

Nervous system involvement in patients with AIDS is frequent either due to direct infection by the HIV-1 or to opportunistic infections or neoplasms. In the present study we evaluate the epidemiologic characteristics of patients in whom the first AIDS manifestation was an indicative neurologic disease (IND) and the influence of such a presenting form in the patients' survival. Out of 1250 reported cases, 252 (20.2%) presented with one of the INDs, according with the CDC AIDS definition criteria. Neither sex nor age differences were found between patients presenting with and without an IND. IVDUs were more likely to present with an IND than homosexual/bisexual men (p = 0.024). Cerebral toxoplasmosis (CT) was the only IND with a significant proportional increase over time. Although some of the IND have a specific treatment, as a whole patients presenting with an IND lived shorter than those presenting with any of the other indicative disorders (p less than 0.0001). The incidence of IND is greater than elsewhere, mainly because of CT. The increment of CT may be in part due to the introduction of the new AIDS definition criteria.

Nutritional support of patients with AIDS

Investigators are now predicting that nearly 100% of the estimated 12 million HIV-positive persons in the world will develop AIDS. Most persons with AIDS will experience progressive weight loss and malnutrition prior to death. Because nutritional therapy clearly has a beneficial effect on the clinical course and immunologic status of the critically ill general population, one must not disregard its potential for benefits in the treatment of persons with AIDS. As a result of the escalating cost of medical therapy and the inevitable AIDS epidemic, the nutritional management of persons with AIDS must be simple to administer and cost effective. The author has developed nutritional screening criteria to identify those patients who would most benefit from nutritional therapy. Because these patients differ in their nutritional requirements, diet tolerance, and degree of gut dysfunction, there is no single nutritional therapy that can be used routinely to treat all malnourished persons with AIDS.

Cerebral lymphoma and HIV encephalitis in a case of paediatric AIDS, with pre-existing multicystic encephalomalacia

A case of intracerebral malignant B cell lymphoma associated with encephalitis typical of Human Immunodeficiency Virus (HIV) infection is described in a 4 year old child, with post-transfusion Acquired Immune Deficiency Syndrome (AIDS) and severe pre-existing cystic encephalomalacia. This report further documents B cell lymphoma as the commonest cause of an intracerebral mass, and an important cause of death in paediatric AIDS. That more than one pathological process may be responsible for neurological symptoms in paediatric AIDS is also emphasised.

Neuronal loss in the frontal cortex in HIV infection

In an attempt to elucidate the cause and mechanism of the dementia and other neurological disorders that can occur in HIV-1 infection, we have quantitatively assessed neuronal populations, by means of a stereological technique (the disector), in the frontal cortex of patients with HIV infection. Eleven of sixty-five brains in the Medical Research Council Central AIDS Brain Bank were selected for study. The selected patients died without opportunistic infection or neoplasm affecting the brain; they had HIV encephalitis or minimal changes. We compared their neuronal counts with those of eight control subjects (seven died of systemic illness, one of pontine haemorrhage which did not affect the cerebral hemispheres). The neuronal numerical density was significantly lower in the HIV group than in the control group (mean [SD] 307 [46] vs 499 [113] x 10(2) per mm3; p less than 0.001). This difference represents a loss of about 38%. There was no significant difference between the HIV subgroups, which suggests that neuronal loss occurs in cases of minor pathology as well as in HIV encephalitis. This finding contributes to the understanding of dementia in AIDS patients and has important implications for their future treatment.

Musculoskeletal Manifestations of Human Immunodeficiency Virus Infection

Human immunodeficiency virus (HIV) causes an infection characterized by a wide spectrum of clinical manifestations, including musculoskeletal conditions that have been recognized with increasing frequency in recent years. Arthralgia, usually of moderate intensity, intermittent, and oligoarticular, is the most frequent rheumatic manifestation of HIV; it occurs in approximately 35% of the cases. Knees, shoulders, and elbows are the most frequently involved joints. A “painful articular syndrome,” characterized by severe articular or bone pain of short duration and absence of inflammation, can be observed in up to 10% of cases. Reiter's syndrome was the first rheumatological disorder recognized in association with HIV infection. The reported frequency has ranged from 0.5 to 9-9%. Most of the patients with this syndrome develop the incomplete form, and they usually are positive for human lymphocyte antigen B27. HIV-associated arthropathy has been observed by several groups. It is characterized by absence of recognizable rheumatic disease or syndrome, an oligoarticular pattern, and a subacute course. Psoriasis and psoriatic arthritis may flare up or develop in the course of an HIV infection and have been reported with increased prevalence in HIV patients. Psoriatic arthritis usually has a polyarticular and asymmetrical pattern. Several forms of myopathy have also been reported. Myalgia and a myopathy similar to polymyositis are the most frequent patterns observed. Two forms of the latter have been recognized, one attributed to HIV infection itself and the other to the use of zidovudine. Septic conditions in joint, bursa, bone, and muscle have rarely been described despite the immunodeficiency state. A Sjogren's syndrome-like disorder, termed “diffuse infiltrative lymphocyte syndrome,” may be seen in HIV patients, and it has many features that distinguish it from primary Sjögren's syndrome. Several types of vasculitis have been described; the necrotizing type is the most frequent type found. Fibromyalgia, hypertrophie osteo-arthropathy, and soft-tissue lesions have also been described. The pathogenetic mechanisms underlying the rheumatic manifestations of HIV infection are not well known. Their treatment is not well defined, but includes conventional antirheumatic therapy. Methotrexate and other immunosuppressive drugs should be used cautiously because they can precipitate the acquired immunodeficiency syndrome in an HIV-positive patient.

Acute hemiplegia associated with HIV infection

An acute hemiplegia secondary to a large cerebral infarct is described in a 16-month-old infant with congenitally-acquired human immunodeficiency virus infection. Serial imaging studies during the next year documented improvement in his hemiplegia and a static underlying human immunodeficiency virus encephalopathy. Acquired immunodeficiency syndrome should be included in the differential diagnosis of children with acute hemiplegia.

Central nervous system myelin: structure, function, and pathology

Multiple sclerosis (MS) and a number of related distinctive diseases are characterized by the active degradation of central nervous system (CNS) myelin, an axonal sheath comprised essentially of proteins and lipids. These demyelinating diseases appear to arise from complex interactions of genetic, immunological, infective, and biochemical mechanisms. While circumstances of MS etiology remain hypothetical, one persistent theme involves recognition by the immune system of myelin-specific antigens derived from myelin basic protein (MBP), the most abundant extrinsic myelin membrane protein, and/or another equally susceptible myelin protein or lipid component. Knowledge of the biochemical and physical-chemical properties of myelin proteins and lipids, particularly their composition, organization, structure, and accessibility with respect to the compacted myelin multilayers, thus becomes central to the understanding of how and why these antigens become selected during the development of MS. This review focuses on current understanding of the molecular basis underlying demyelinating disease as it may relate to the impact of the various protein and lipid components on myelin morphology; the precise molecular architecture of this membrane as dictated by protein-lipid and lipid-lipid interactions; and the relationship, if any, between the protein/lipid components and the destruction of myelin in pathological situations.

Subclinical peripheral nerve involvement in AIDS: an electrophysiological and pathological study

Thirty patients with AIDS without symptoms or signs of peripheral neuropathy were compared electrophysiologically with 23 age and sex matched healthy controls. The patients had a mean reduction in the amplitude of common peroneal compound muscle action potentials of 37% (95% CI 11-70%) and of sural sensory action potentials of 34% (CI 18-49%). Mean conduction velocity of both motor and sensory nerves was reduced by between 1 and 7 m/s, with a prolongation of F waves corrected for height of 5% in the arms and 13% in the legs. The distal motor latencies were unchanged. These changes did not correlate with the duration of AIDS, degree of immunosuppression (CD4 count), Body Mass Index, albumin or vitamin B12 level. Four patients had subclinical mononeuropathies. Sural nerve taken at necropsy from five asymptomatic AIDS patients had evidence of axonal degeneration without inflammation or demyelination. There was a mean reduction in myelinated fibre density of 30.5% (CI 10-51%) compared with eight age matched sudden death controls (p = 0.01). This loss principally affected the larger fibres. The pathological and electrophysiological changes indicate axonal degeneration and are similar to those seen in other chronic disorders and in normal ageing. It is concluded that this axonal degeneration is not specific to HIV.

Dementia associated with human immunodeficiency virus: subcortical or cortical?

Two different types of dementia and corresponding neuropathological findings of patients with human immunodeficiency virus (HIV) infection are presented. In one case, "subcortical" dementia with slow movements and mental processes as well as problems in active recall but without focal defects corresponded to diffuse leukoencephalopathy. In another case, "cortical" dementia with impaired abstraction and memory as well as several focal defects corresponded to microglial nodules in cortical and in deep grey matter, with only a mild diffuse leukoencephalopathy. Thus, in contrast to earlier interpretations, subcortical dementia does not appear to be the only form of dementia in HIV-infected patients, and cortical dysfunction may also occur.

Macrophage- and astrocyte-derived transforming growth factor beta as a mediator of central nervous system dysfunction in acquired immune deficiency syndrome

The multifunctional cytokine, transforming growth factor beta (TGF-beta), was identified by immunocytochemistry in the brain tissues of four patients with acquired immune deficiency syndrome (AIDS), but not in control brain tissue. The TGF-beta staining was localized to cells of monocytic lineage as well as astrocytes, especially in areas of brain pathology. In addition, the brain tissues from the AIDS patients contained transcripts for human immunodeficiency virus 1 (HIV-1) by in situ hybridization, suggesting a correlation between the presence of HIV-1 in the brain and the expression of TGF-beta. However, the expression of TGF-beta was not limited to HIV-1-positive cells, raising the possibility of alternative mechanisms for the induction of TGF-beta in these AIDS patients' brains. To investigate these mechanisms, purified human monocytes were infected in vitro with HIV-1 and were shown to secrete increased levels of TGF-beta. In addition, HIV-1-infected monocytes released a factor(s) capable of triggering cultured astrocytes that are not infected with HIV-1 to secrete TGF-beta. The release of TGF-beta, which is an extremely potent chemotactic factor, may contribute to the recruitment of HIV-1-infected monocytic cells, enabling viral spread to and within the central nervous system (CNS). Moreover, TGF-beta augments cytokine production, including cytokines known to be neurotoxic. The identification of TGF-beta within the CNS implicates this cytokine in the immunopathologic processes responsible for AIDS-related CNS dysfunction.

AIDS dementia complex and HIV-1 infection: a view from the clinic

The AIDS dementia complex (ADC) is a clinical syndrome which characteristically presents as a "subcortical dementia" with cognitive, motor and behavioral changes. While the pathogenesis remains puzzling in a number of critical aspects, ADC likely relates in a fundamental way to HIV-1, itself, rather than to a secondary, opportunistic condition. This review focuses on some of the clinical information which bears on the pathogenesis of this syndrome and its relation to HIV-1 infection. This information derives from studies of the clinical character of ADC, its epidemiology and natural history, cerebrospinal fluid analysis, neuroimaging results, clinical correlates of pathological findings and its response to antiviral therapy.

Skeletal muscle involvement in human immunodeficiency virus infection

In addition to muscle changes due to peripheral nervous system involvement, primary myopathic changes associated with the human immunodeficiency virus (HIV) have also been described. We studied seven cases: two had developed an acquired immunodeficiency syndrome (AIDS), four had seroconverted to HIV but were otherwise asymptomatic, one was HIV seronegative when the biopsy was performed and one was biopsied twice. Besides the HIV no other infectious agent was detected. Muscle biopsies showed: (a) muscle fiber necrosis and regeneration; (b) inflammatory changes with moderate perivascular infiltration; and (c) unusual myofibrillary disorganization. Immunocytochemical techniques using anti-HIV monoclonal antibodies showed the presence of the virus in one biopsy. HIV-RNA was detected by in situ hybridization in the same biopsy. With both techniques the HIV was detected in isolated mononuclear cells in the muscle endomysium and not within the muscle fibers. Muscle involvement associated with HIV infection may be related, at least in some cases, to the presence of the virus in interstitial cells.

Treatment of acute toxoplasmosis with oral clindamycin

The combination of pyrimethamine and clindamycin, both administered orally, was evaluated for initial and maintenance therapy of toxoplasmosis in eight AIDS patients who were either allergic to sulfonamides or unresponsive to standard therapy. Symptomatic and neuroradiographic improvement occurred in the majority of patients. The regimen was well tolerated and associated with minimal toxicity, and appeared to be an effective alternative to standard therapy.

HIV encephalopathy: incidence, definition and pathogenesis. Results of a Swiss collaborative study

The incidence of HIV encephalopathies was determined in an ongoing consecutive autopsy study. Among 345 patients who died from AIDS in Switzerland during 1981-1990, 68 (19%) showed morphological evidence of HIV encephalopathy. Two major histopathological manifestations were observed. Progressive diffuse leukoencephalopathy (PDL) was present in 33 cases and is characterized by a diffuse loss of myelin staining in the deep white matter of the cerebral and cerebellar hemispheres, with scattered multinucleated giant cells but little or no inflammatory reaction. Multinucleated giant cell encephalitis (MGCE) was diagnosed in 32 cases; it's hallmarks are accumulations of multinucleated giant cells with prominent inflammatory reaction and focal necroses. In 3 patients both types of lesions overlapped. Brain tissue from 27 patients was analyzed for the presence of HIV gag sequences using the polymerase chain reaction (PCR) with primers encoding a 109 base pair segment of the viral gene. Amplification succeeded in all patients with clinical and histopathological evidence for HIV encephalopathy but was absent in AIDS patients with opportunistic bacterial, parasitic and/or viral infections. Potential mechanisms by which HIV exerts it's adverse effects on the human CNS are discussed.

The definition of HIV-specific neuropathology

Evaluation of a neuropathological series of 160 HIV-infected patients, almost all in the terminal AIDS stage of the infection, allowed recognition of novel syndromes which can be regarded as HIV-specific neuropathology because: 1) they are not observed in non-HIV tissues; 2) HIV is, in our hands consistently by immunocytochemistry, demonstrable in large amounts within these lesions; 3) other pathogens are not detectable within these lesions; and 4) these lesions may occur in isolated fashion within CNS tissues (40% of HIV-specific neuropathology in this series), without any other CNS pathology. HIV-specific neuropathology was found in 34% in this series and comprised two prototypes within a spectrum of frequently overlapping changes: multifocal microgranulomatous lesions of HIV encephalitis, and diffuse white matter damage of HIV leukoencephalopathy. In almost all cases, multinucleated giant cells signal the local presence of HIV in routine stains. In contrast to HIV-specific neuropathology, various unspecific nervous tissue syndromes do not consistently exhibit the local presence of HIV and thus are designated HIV-associated or possibly HIV-induced lesions: lymphocytic meningitis, vacuolar myelopathy, multifocal vacuolar leukoencephalopathy, and diffuse poliodystrophy. Although these unspecific syndromes may also contribute to clinical manifestations, their pathogenetic relation with HIV remains to be established.

Studies of the susceptibility of Pneumocystis carinii to clindamycin/primaquine in rats

Studies in rat models showed that the combination of primaquine plus clindamycin was effective in the therapy and prophylaxis of Pneumocystis carinii pneumonia and that the combination was more effective than either drug alone. These studies formed the basis of ongoing clinical therapy studies and provide a basis for clinical studies of prophylactic efficacy.

Evidence for neurotoxic activity of tat from human immunodeficiency virus type 1

The human immunodeficiency virus (HIV) genome codes for a trans-activating regulatory protein, tat. Using chemically synthesized tat, it was found that 125I-tat and 125I-tat38-86 specifically bound to rat brain synaptosomal membranes with moderate affinity (K0.5 = 3 microM). Interaction of tat with nerve cells was also revealed by flow cytometry, which showed its binding to rat glioma and murine neuroblastoma cells, using both direct fluorescence with fluorescein isothiocyanate-labeled tat and indirect immunofluorescence assays. This interaction was investigated with electrophysiology using isolated excitable frog muscle fibers and cockroach giant interneuron synapses. tat acted on the cell membrane and induced a large depolarization, accompanied by a decrease in membrane resistance, thereby modifying cell permeability. The neurotoxicity of tat was further demonstrated in vitro, on glioma and neuroblastoma cell growth, as well as by a 51Cr release assay in both tumor cell lines. Interestingly, no hemolytic activity of tat for human erythrocytes was found even when tat was tested at its highly neurotoxic concentration. Experiments in vivo showed that synthetic tat is a potent and lethal neurotoxic agent in mice. The use of tat peptide derivatives showed that basic region from 49 to 57 is necessary and sufficient for binding to cell membranes and toxicity.

Cytomegalovirus neuropathy in acquired immunodeficiency syndrome: a clinical and pathological study

We have observed typical cytomegalovirus cytopathology associated with multifocal inflammatory and necrotic lesions of peripheral nerve in biopsy specimens from 4 patients who developed a rapidly progressive, multifocal neuropathy late in the course of human immunodeficiency virus infection. The inflammatory infiltrates, which contained numerous polymorphonuclear cells, were associated with mixed, axonal, and demyelinative lesions of nerve fibers. One of these patients improved on treatment with DHPG (9-[2-hydroxy-l(hydroxymethyl) ethoxymethyl] guanine) and remains stable after 18 months. The other 3 died soon after the onset of the neuropathy. In another patient with acquired immunodeficiency syndrome, who developed a severe, predominantly motor neuropathy of the lower limbs, the nerve biopsy did not reveal cytomegalovirus inclusions, but the neurological deficit improved on treatment with DHPG. The patient died from cachexia 2 months later; numerous cytomegalovirus lesions were found in the spinal cord at the time of postmortem examination. The multifocal necrotic endoneurial nerve lesions with polymorphonuclear cell infiltration we describe may help identify cytomegalovirus neuropathy when characteristic inclusions are not present in the biopsy specimen.

Ischaemic myelopathy secondary to disseminated intravascular coagulation in AIDS

A 39-year-old patient with AIDS presented with a rapidly progressive myelopathy with a partial Brown-Séquard syndrome. He died, 9 weeks after onset of the first neurological signs, from diffuse encephalopathy. Neuropathological examination revealed multiple, usually small, frequently haemorrhagic, infarcts or various ages and numerous fibrin thrombi in medium and small penetrating vessels and capillaries of the brain and spinal cord, characteristic of disseminated intravascular coagulation. There were no inflammatory changes. Immunohistochemical studies for human immunodeficiency virus, cytomegalovirus, varicella zoster virus, herpes simplex virus type 1 and type 2 were negative. Ischaemic spinal cord lesions due to disseminated intravascular coagulation may represent an unusual cause of focal, non-inflammatory, non-tumoral, myelopathic syndrome in AIDS.

AIDS virus infection and autoimmunity: a perspective of the clinical, immunological, and molecular origins of the autoallergic pathologies associated with HIV disease

The acquired immune deficiency syndrome (AIDS) is a viral-induced disorder of humans that is reaching pandemic proportions. The etiologic agent responsible for AIDS is recognized as a retrovirus termed the human immunodeficiency virus (HIV). This virus is both cytotropic and cytopathic for T lymphocytes in vitro, and patients with AIDS and HIV-related conditions invariably have serious T cell abnormalities, notably a reduced number of the helper/inducer (CD4+) subpopulation. There is now a substantial body of evidence to suggest that the AIDS virus triggers a diverse range of autoimmune phenomena. The purpose of this article is to summarize the clinical and immunopathological manifestations of autoimmunity in HIV infection and to provide a perspective of the possible origins and roles autoimmune reactions play in HIV disease progression.

Intrathecal IgG synthesis and specificity of oligoclonal IgG in patients infected with HIV-1 do not correlate with CNS disease

The CSF/serum immune response to HIV 1 was studied in 24 patients admitted for investigation. The level of antibody to HIV-1 and specificity of oligoclonal IgG were determined in blood and cerebrospinal fluid (CSF). The majority of patients demonstrated elevated levels of intrathecal IgG synthesis, with levels of HIV-1-specific antibody frequently being significantly higher in CSF than in serum. In 16 of 21 patients the CSF/serum antibody ratio indicated active intrathecal synthesis. Oligoclonal banding was present in CSF from all 24 patients. Immunoprinting of serum and CSF demonstrated antigenic specificity (p24, gp 160, RT) of the clonal antibodies in all of 12 patients though the patterns of reactivity in CSF did not necessarily correspond with that of serum. Although a specific association of particular patterns with HIV CNS disease was not found we feel that these markers should be included in longitudinal studies of HIV-related diseases of the CNS. The specificity of oligoclonal antibodies, both in CSF and in serum was demonstrated, and this specificity may be a useful marker for longitudinal studies in HIV-1 antibody-positive asymptomatic patients.

Infection as a risk factor for infarction and atherosclerosis

A growing amount of clinical and experimental evidence suggests a link between infection and atherosclerotic diseases including both myocardial and cerebral infarction. A prime example is a greatly increased risk of stroke in septicaemic patients with and without endocarditis. Controlled clinical studies have recently shown, however, that certain other milder bacterial infections are also a risk factor for infarction. A preceding febrile respiratory infection was a major risk factor for stroke in young and middle aged patients. In patients with acute myocardial infarction Chlamydia pneumoniae and dental infections seem to be risk factors according to one controlled clinical study. Several possible mechanisms could explain the observed association of infection and infarction. For instance, infection causes a hypercoagulable state which increases the risk of thrombosis. In addition, infection has profound and harmful effects on prostaglandin and lipid metabolism. Infection may also have some role in the atherosclerotic process itself by inducing damage and inflammation in vascular endothelium in the presence of hypercholesterolemia. So far, however, little clinical evidence is available to suggest that by controlling infection the risk of infarction or development of atherosclerotic lesions might be reduced except in patients with endocarditis, where the risk of thromboembolic complications rapidly diminished when the infection is controlled with antimicrobial therapy.

Neurologic and psychiatric manifestations of HIV disease

Neuropsychiatric problems have assumed an increasingly prominent role in HIV-infected individuals. Disease occurs at all levels of the central and peripheral nervous systems by a variety of mechanisms. The AIDS dementia complex is the prototypical example of "direct" effects of HIV on the neuraxis, while infections such as toxoplasmosis and cryptococcal meningitis are complications of HIV-induced immunosuppression. Neurologic manifestations vary in frequency depending upon the overall stage of HIV disease; diagnostic difficulties may be encountered because of HIV's effect on cerebrospinal fluid parameters. The uncertainties of management of neurosyphilis in this setting provide and example of these problems. As is the case with other organ systems, the main goal of neurodiagnostic efforts is to find the increasing number of treatable components of neuropsychiatric dysfunction.

Myoclonic epilepsy in an HIV positive patient: neurophysiological findings

An HIV-positive patient is described who presented with action myoclonus. Unusually, focal sinusoidal EEG burst complexes with a frequency of 40 and 55 Hz could be recorded over the sensorimotor cortex. Activity having a similar frequency was evoked in this area by posterior tibial nerve stimulation in the affected leg, and jerk-locked averaging showed that myoclonic jerks were preceded by similar cortical sinusoidal waves.

Secretion of neurotoxins by mononuclear phagocytes infected with HIV-1

Mononuclear phagocytes (microglia, macrophages, and macrophage-like giant cells) are the principal cellular targets for human immunodeficiency virus-1 (HIV-1) in the central nervous system (CNS). Since HIV-1 does not directly infect neurons, the causes for CNS dysfunction in acquired immunodeficiency syndrome (AIDS) remain uncertain. HIV-1-infected human monocytoid cells, but not infected human lymphoid cells, released toxic agents that destroy chick and rat neurons in culture. These neurotoxins were small, heat-stable, protease-resistant molecules that act by way of N-methyl-D-aspartate receptors. Macrophages and microglia infected with HIV-1 may produce neurologic disease through chronic secretion of neurotoxic factors.

Symptomatic polyneuropathy in human immunodeficiency virus antibody seropositive men with and without immune deficiency: a comparative electrophysiological study

Symptomatic polyneuropathy in human immunodeficiency virus (HIV) infection was studied in ten men with acquired immunodeficiency syndrome (AIDS) and in ten men without the immune deficiency. In both groups of patients electrophysiological signs of polyneuropathy of the axonal type were present in the sural, median and peroneal nerves. The AIDS patients had a greater reduction of the mean (SD) sural nerve action potential, 3.1 (2.7) microV, than in patients without AIDS, 10.2 (6.1) microV (p less than 0.01) and greater slowing of peroneal nerve conduction velocity, 42.6 (1.4) m/s in AIDS patients versus 52.6 (3.3) m/s in patients without AIDS (p less than 0.0001). These findings indicate that in most HIV infected patients the severity but not the type of neuropathy depends on whether an immune deficient state has developed. Seven patients with symptomatic polyneuropathy were treated with azidothymidine (AZT) for an average of 10 months and compared with a group of five untreated patients with similar symptoms. No effect of AZT treatment on sural or median nerve amplitude or conduction velocity or on the vibratory or temperature thresholds was observed.

Acquired rod-body myopathy associated with human immunodeficiency virus infection

A 35 year old homosexual man showed clinical features of myopathy, with progressive muscular weakness of proximal muscles. EMG demonstrated a myopathic pattern; serum CPK was mildly elevated and CSF examination revealed antibodies to HIV and a blood-brain barrier damage. An open biopsy of the quadriceps femoris muscle showed myopathic changes with inflammatory features including a marked variation in fiber size, necrotic fibers and phagocytosis, a profusion of internal nuclei. Fiber type analysis with myosin ATPase reaction revealed that myopathic changes involved both fiber types. Changes in the oxidative enzyme activities were also observed in the degenerating muscle fibers. Electron microscopy showed patterns of myofibrillar degeneration and characteristic rod bodies in 30% of fibers. The close resemblance of the present morphological results with those recently observed in some HIV antibody positive men seems to indicate the existence of a specific structural myopathy associated with AIDS.

Toxoplasmosis of the conus medullaris in a patient with hemophilia A-associated AIDS. Case report

Toxoplasma gondii has been reported to be the most common cause of focal brain lesions in patients with acquired immunodeficiency syndrome (AIDS). A case of intramedullary toxoplasmosis of the conus medullaris is reported in a patient with hemophilia A-associated AIDS. The diagnosis is discussed, with particular emphasis on the magnetic resonance imaging appearance.

Otologic pathophysiology in patients with human immunodeficiency virus

During the initial phase of clinical diagnosis and treatment of the manifestations of acquired immunodeficiency syndrome, involvement of the ear appeared minor. In the past several years, however, otologic disorders increasingly have been reported in individuals with human immunodeficiency virus (HIV), as well as in retrospective studies of such patients. The otologic data appear quite variable. Functionally, conductive hearing loss, unilateral and bilateral sudden or progressive sensorineural hearing losses, vertigo, and tinnitus have been reported. In addition, tissue responses in each division of the ear have been observed. Based on collective serologic and immunologic diagnostic assays, clinical histories, and temporal bone histopathology, otologic symptoms may not be the direct effect of HIV alone, but rather a combination of the effects of HIV infection coupled with that of opportunistic microorganisms and/or possible ototoxic effects of certain therapeutic agents. It is within this context that otologic findings in this population of subjects will be discussed.

Cerebrospinal fluid interleukin-6 activity in HIV infection and inflammatory and noninflammatory diseases of the nervous system

Interleukin-6 (IL-6) activity was measured in the cerebrospinal fluid (CSF) of patients at different stages of human immunodeficiency (HIV) virus infection and of patients with multiple sclerosis (MS) or other inflammatory (OID) and noninflammatory neurological diseases (OND). In the advanced stages of HIV infection and in OID, IL-6 was detected more frequently (80 and 75% of the cases) and at higher concentrations than in the early stages of HIV infection. MS and OND (44, 48, and 44% of cases). Analysis of CSF and paired sera indicated that IL-6 production can be compartmentalized to either of the fluids. Evidence that altered blood-brain barrier functions can, at least in part, influence the CSF IL-6 levels was found in OID patients. No association was evident between intrathecal immunoglobulin synthesis and CSF IL-6 levels. Interleukin-1 (IL-1) levels were detectable in a minority of the samples from neurological patients; one OID patient had high levels of both CSF IL-1 and IL-6.