Acute encephalopathy coincident with seroconversion for anti-HTLV-III

Legacy effect on neuropsychological function in HIV-infected men on combination antiretroviral therapy

OBJECTIVE

To determine whether combination antiretroviral therapy (cART) initiation alters the trajectory of cognitive performance in HIV+ men, and whether cognition prior to cART predicts postcART function.

DESIGN

Longitudinal cohort study. Multicenter AIDS Cohort Study.

METHODS

From an initial set of 3701 men with complete neuropsychological data, men with HIV infection were initially matched with men without infection on cognitive status, race, age, and timeline (T0 defined as cART initiation). Propensity score matching was then used to match pairs on depressive symptoms at T0, education, T0 cognitive scores, and recruitment cohort. There were 506 matched pairs of infected and uninfected men in the final analysis. Mixed effect models were constructed to analyze the trajectories of cognitive functions and to test the effect of cART and HIV on cognitive functions over time.

RESULTS

Performance in each cognitive domain did not change following the initiation of cART among HIV-infected men with prior impairment and was comparable to the performance of their matched uninfected men. However, among the infected men who were unimpaired prior to cART, motor function declined significantly faster than it did for uninfected controls.

CONCLUSIONS

Cognitive dysfunction is persistent in HIV-infected men and cART does not alter the trajectory of cognitive decline in men who were impaired prior to effective therapy. This suggests that current cognitive impairment in HIV+ men results from a legacy effect, and from factors other than the HIV itself. Furthermore, motor skills may be uniquely vulnerable to the virus, cART, or age-related co-morbidities.

Review of the neurological aspects of HIV infection

There are almost 40 million people in the world who live with the human immunodeficiency virus (HIV). The neurological manifestations associated with HIV contribute to significant morbidity and mortality despite the advances made with anti-retroviral therapy (ART). This review presents an approach to classification of neurological disorders in HIV, differentiating diseases due to the virus itself and those due to opportunistic infection. The effects of antiretroviral therapy are also discussed. The emphasis is on the developing world where advanced complications of HIV itself and infections such as tuberculosis (TB), toxoplasmosis and cryptococcal meningitis remain prevalent.

Potential for early antiretroviral therapy to reduce central nervous system HIV-1 persistence

: Although treatment with antiretroviral therapy (ART) improves central nervous inflammation, limits viral replication detected in the cerebrospinal fluid, and prevents severe clinical neurological disease in most individuals, HIV-1 can persist in the central nervous system (CNS) despite ART. Recent observations that initiation of ART early in the course of infection limits the size of systemic HIV reservoirs, parallel clinical reports of increased rates of posttreatment viral control in early treatment cohorts, and an understanding of the dynamics of HIV-1 infection and neuropathogenesis during early infection provides rationale to consider that ART started early in the course of HIV-1 infection may have a beneficial effect on CNS HIV-1 persistence. Early ART may restrict the initial establishment of HIV-1 infection in cells of the CNS, and furthermore, may reduce levels of immune activation and inflammation that allow perpetuation of CNS infection. In this review, we consider the precedent set by studies of the impact of early treatment on systemic HIV-1 reservoirs, summarize the current understanding of early CNS HIV-1 exposure and its effects, and examine the evidence for a benefit in the CNS compartment of early treatment.

HIV-associated synaptic degeneration

Human immunodeficiency virus (HIV) infection induces neuronal injuries, with almost 50% of infected individuals developing HIV-associated neurocognitive disorders (HAND). Although highly activate antiretroviral therapy (HAART) has significantly reduced the incidence of severe dementia, the overall prevalence of HAND remains high. Synaptic degeneration is emerging as one of the most relevant neuropathologies associate with HAND. Previous studies have reported critical roles of viral proteins and inflammatory responses in this pathogenesis. Infected cells, including macrophages, microglia and astrocytes, may release viral proteins and other neurotoxins to stimulate neurons and cause excessive calcium influx, overproduction of free radicals and disruption of neurotransmitter hemostasis. The dysregulation of neural circuits likely leads to synaptic damage and loss. Identification of the specific mechanism of the synaptic degeneration may facilitate the development of effective therapeutic approaches to treat HAND.

Atypical presentations of acute disseminated encephalomyelitis (ADEM) in HIV infection

Acute disseminated encephalomyelitis is a monophasic demyelinating disorder of the central nervous system associated with various viral infections including HIV infection. We present the findings of seven HIV-infected patients with mild to moderate immunosuppression presenting with atypical features. Four patients had a multiphasic course; three patients had tumefactive lesions, and two patients had corpus callosum lesions. Two patients with the multiphasic course also had tumefactive lesions. Their clinical and radiological findings are presented. Despite the few cases, we propose that the dysimmune process lying between marked immunosuppression (CD4 < 200 cells/μL) and normal CD4 counts (CD4 > 500 cells/μL) might be responsible for these atypical presentations.

Abnormalities of Liver Function during HIV Seroconversion Illness

In 6 patients with a severe human immunodeficiency virus (HIV) seroconversion illness distinct abnormalities of liver transaminases were observed; in addition there was marked hepatomegaly in 5 patients.

Neurologic signs and symptoms frequently manifest in acute HIV infection

OBJECTIVE

To determine the incidence, timing, and severity of neurologic findings in acute HIV infection (pre-antibody seroconversion), as well as persistence with combination antiretroviral therapy (cART).

METHODS

Participants identified with acute HIV were enrolled, underwent structured neurologic evaluations, immediately initiated cART, and were followed with neurologic evaluations at 4 and 12 weeks. Concurrent brain MRIs and both viral and inflammatory markers in plasma and CSF were obtained.

RESULTS

Median estimated HIV infection duration was 19 days (range 3-56) at study entry for the 139 participants evaluated. Seventy-three participants (53%) experienced one or more neurologic findings in the 12 weeks after diagnosis, with one developing a fulminant neurologic manifestation (Guillain-Barré syndrome). A total of 245 neurologic findings were noted, reflecting cognitive symptoms (33%), motor findings (34%), and neuropathy (11%). Nearly half of the neurologic findings (n = 121, 49%) occurred at diagnosis, prior to cART initiation, and most of these (n = 110, 90%) remitted concurrent with 1 month on treatment. Only 9% of neurologic findings (n = 22) persisted at 24 weeks on cART. Nearly all neurologic findings (n = 236, 96%) were categorized as mild in severity. No structural neuroimaging abnormalities were observed. Participants with neurologic findings had a higher mean plasma log10 HIV RNA at diagnosis compared to those without neurologic findings (5.9 vs 5.4; p = 0.006).

CONCLUSIONS

Acute HIV infection is commonly associated with mild neurologic findings that largely remit while on treatment, and may be mediated by direct viral factors. Severe neurologic manifestations are infrequent in treated acute HIV.

Viral encephalitis in the ICU

Viral encephalitis causes an altered level of consciousness, which may be associated with fever, seizures, focal deficits, CSF pleocytosis, and abnormal neuroimaging. Potential pathogens include HSV, VZV, enterovirus, and in some regions, arboviruses. Autoimmune (eg, anti-NMDA receptor) and paraneoplastic encephalitis are responsible for some cases where no pathogen is identified. Indications for ICU admission include coma, status epilepticus and respiratory failure. Timely initiation of anti-viral therapy is crucial while relevant molecular and serological test results are being performed. Supportive care should be directed at the prevention and treatment of cerebral edema and other physiological derangements which may contribute to secondary neurological injury.

Encephalitis in primary HIV infection: challenges in diagnosis and treatment

We report a case of primary HIV encephalitis, which initially presented as acute psychosis. Magnetic resonance imaging of the brain was suggestive of vasculitis and multiple infarctions, whereas a brain biopsy after six weeks of symptoms showed HIV encephalitis with microglial nodules, but no signs of vasculitis. We review previous reported cases and radiological findings in HIV encephalitis and discuss the role of antiretroviral therapy and steroids in its management.

Genotypical diversity of HIV clades and central nervous system impairment

The central nervous system (CNS) and the immune system are considered major target organs for HIV infection. The neurological manifestations directly related to HIV are acute viral meningitis, chronic meningitis, HIV associated dementia, vacuolar myelopathy and involvement of the peripheral nervous system. Changes in diagnosis and clinical management have changed the aspect of HIV infection so that it is no longer a fatal disease, and has become a chronic disease requiring sustained medical management. After HAART the incidence of most opportunistic infections, including those affecting the CNS, has dropped markedly. Some studies suggest that neurological involvement of infected patient occur with different frequency, depending on HIV subtype involved in the infection. Subtype C may have reduced neuroinvasive capacity, possibly due to its different primary conformation of HIV transactivating regulatory protein (Tat), involved in monocyte chemotaxis. This review focus on physiopathologic aspects of HIV infection in CNS and its correlation with HIV clades.

Central nervous system immune activation characterizes primary human immunodeficiency virus 1 infection even in participants with minimal cerebrospinal fluid viral burden

BACKGROUND

Central nervous system (CNS) human immunodeficiency virus (HIV) infection and immune activation lead to brain injury and neurological impairment. Although HIV enters the nervous system soon after transmission, the magnitude of infection and immunoactivation within the CNS during primary HIV infection (PHI) has not been characterized.

METHODS

This cross-sectional study analyzed cerebrospinal fluid (CSF) and blood from 96 participants with PHI and compared them with samples from neuroasymptomatic participants with chronic infection and ≥ 200 or < 200 blood CD4 T cells/μL, and with samples from HIV-seronegative participants with respect to CSF and plasma HIV RNA, CSF to serum albumin ratio, and CSF white blood cell counts (WBC), neopterin levels, and concentrations of chemokines CXCL10 and CCL2.

RESULTS

The PHI participants (median 77 days post transmission) had CSF HIV RNA, WBC, neopterin, and CXCL10 concentrations similar to the chronic infection participants but uniquely high albumin ratios. 18 participants had ≤ 100 copies/mL CSF HIV RNA, which was associated with low CSF to plasma HIV ratios and levels of CSF inflammation lower than in other PHI participants but higher than in HIV-seronegative controls.

CONCLUSIONS

Prominent CNS infection and immune activation is evident during the first months after HIV transmission, though a proportion of PHI patients demonstrate relatively reduced CSF HIV RNA and inflammation during this early period.

Acute transient inflammatory leukoencephalopathy in HIV

HIV-related acute inflammatory leukoencephalopathy of undetermined origin (AIL) is characterized by abrupt onset of symptoms generally associated with focal brain lesions and inflammatory CSF findings. A previously asymptomatic 31-year-old HIV+ woman presented with acute cognitive difficulties, right hemiparesis and dysphasia. Brain MRI showed a large contrast-enhancing lesion in the left frontal lobe; brain biopsy revealed an inflammatory process. No etiological agent was found in blood, CSF or brain tissue. The patient was given systemic steroids and gammaglobulins and put on HAART. Clinical conditions progressively and completely recovered. Further brain MRI showed the shrinkage of the lesion with no contrast enhancement. Our case could be classified as AIL in HIV resembling ADEM pattern and highlights the importance of taking into consideration. ADEM in the diagnostic process of HIV-related leukoencephalopathy even if the typical features are lacking, as immunodeficiency could modify both presentation and disease course.

HIV-related acute inflammatory leukoencephalopathy of undetermined origin: review of the literature

HIV-related acute inflammatory leukoencephalopathy of undetermined origin (AIL) has been anecdotally described in literature as being responsible for cognitive and motor deficits. We carried out a review of all the cases of AIL published in literature. Articles were selected according to 2 criteria: acute onset of symptoms; undetermined aetiology and non-fulfilment of multiple sclerosis diagnostic criteria. They were then analyzed in terms of clinical, biological and instrumental features, therapy, diagnostic classification and prognosis. Although rare (21 patients out of about 4,000 publications), AIL is of particular interest, as the comprehension of its mechanisms could give some insight into the direct and immune-mediated actions of HIV within the brain. All the reported patients share several clinical, histopathological, radiological and CSF features, leading to hypothesize a similar aetiopathogenetic mechanism. Conversely, we observed a high heterogeneity of treatment and diagnostic classification, which could have conditioned the broad prognostic variability. The absence of a defined aetiology leads to consider these forms as a particular subgroup of not determined leucoencephalopathies (NDLE), with both MRI and histological pattern dominated by inflammation as distinctive feature.

Neurological disease: the effects of HIV and antiretroviral therapy and the implications for early antiretroviral therapy initiation

PURPOSE OF REVIEW

The purpose of this review is to examine the literature regarding HIV-associated neurocognitive disorders, early HIV infection of the central nervous system (CNS), the role of the peripheral immune system in controlling HIV infection and disease within the brain and the potential role that early antiretroviral treatment may play in the preservation of neurocognitive health in patients with more than 500 CD4+ cells/microl.

RECENT FINDINGS

In the post highly active antiretroviral therapy (HAART) era, HIV-associated neurocognitive disorders remain prevalent and even mild-moderate immunosuppression carries a risk for the development of HIV-associated dementia. HIV infection of the CNS occurs early in the illness, and data suggest that a robust peripheral immune system is key to the long-term control of CNS HIV infection. HAART results in clinical, neuropsychological and neuroradiological improvement in patients with HIV-associated neurocognitive disorders, and the prescription of HAART regimens with good cerebrospinal fluid penetration appears to be preferable in this setting. There is little evidence that HAART causes CNS toxicity. The benefits and risks of HAART in the preservation or enhancement of neurocognitive function in well, HIV-infected patients with more than 500 CD4+ cells/microl are unknown.

SUMMARY

The prescription of HAART in well, HIV-infected patients with high CD4+ cell counts may afford enhanced control of CNS HIV infection as a result of the benefits of HAART upon peripheral immune function. In turn, this may result in superior or preserved neurocognitive performance in comparison to the current practice of commencing HAART when CD4+ cells reach 350 cells/microl or lower. This hypothesis will be tested in an upcoming randomized clinical trial.

Acute encephalopathy and multi-organ involvement with rhabdomyolysis during primary HIV infection

An adolescent male developed encephalopathy and multiple organ involvement with rhabdomyolysis during primary HIV infection (PHI). All symptoms and signs resolved within a few days. Nineteen cases of central nervous system complications (other than aseptic meningitis) have been reported in PHI. These include encephalopathy, meningoencephalitis, acute disseminated encephalomyelitis, multiple sclerosis, myelopathy, and meningoradiculitis. Half of the patients died or suffered sequelae. Except in cases of multiple sclerosis, steroids were not of benefit. Initiation of antiretrovirals during PHI remains controversial. Rhabdomyolysis was reported in eight patients with PHI. All patients recovered. Primary HIV infection should be considered when the clinician faces patients with unexplained neurologic manifestations, rhabdomyolysis, or multiple organ involvement.

Initial B-cell responses to transmitted human immunodeficiency virus type 1: virion-binding immunoglobulin M (IgM) and IgG antibodies followed by plasma anti-gp41 antibodies with ineffective control of initial viremia

A window of opportunity for immune responses to extinguish human immunodeficiency virus type 1 (HIV-1) exists from the moment of transmission through establishment of the latent pool of HIV-1-infected cells. A critical time to study the initial immune responses to the transmitted/founder virus is the eclipse phase of HIV-1 infection (time from transmission to the first appearance of plasma virus), but, to date, this period has been logistically difficult to analyze. To probe B-cell responses immediately following HIV-1 transmission, we have determined envelope-specific antibody responses to autologous and consensus Envs in plasma donors from the United States for whom frequent plasma samples were available at time points immediately before, during, and after HIV-1 plasma viral load (VL) ramp-up in acute infection, and we have modeled the antibody effect on the kinetics of plasma viremia. The first detectable B-cell response was in the form of immune complexes 8 days after plasma virus detection, whereas the first free plasma anti-HIV-1 antibody was to gp41 and appeared 13 days after the appearance of plasma virus. In contrast, envelope gp120-specific antibodies were delayed an additional 14 days. Mathematical modeling of the earliest viral dynamics was performed to determine the impact of antibody on HIV replication in vivo as assessed by plasma VL. Including the initial anti-gp41 immunoglobulin G (IgG), IgM, or both responses in the model did not significantly impact the early dynamics of plasma VL. These results demonstrate that the first IgM and IgG antibodies induced by transmitted HIV-1 are capable of binding virions but have little impact on acute-phase viremia at the timing and magnitude that they occur in natural infection.

Preventing brain damage in HIV infection

HIV-1 is a virus with neurotropic features causing major morbidity and also mortality if untreated. Mild symptoms of neurocognitive impairment are common and precede more severe forms of dementia, termed AIDS dementia complex (ADC). The pathogenesis of neurodegeneration in HIV-1 infection is not fully understood, and we lack specific markers to verify the diagnosis. Fortunately, antiretroviral treatment is effective in treating both systemic and CNS infection, and neurocognitive symptoms and ADC will, in most cases, improve on treatment. This review focuses on current research regarding cerebral spinal fluid biomarkers and effects of highly active antiretroviral treatment on HIV-1 CNS disease.

Neuropathologic contributions to understanding AIDS and the central nervous system

This historical review describes the evolution of the pathogenetic concepts associated with infection by the Human Immunodeficiency Virus (HIV), with emphasis on the pathology of the nervous system. Although the first descriptions of damage to the nervous system in the acquired immunodeficiency syndrome (AIDS) only appeared in 1982, the dramatic diffusion of the epidemic worldwide and the invariably rapidly fatal outcome of the disease, before the introduction of efficient treatment, generated from the beginning an enormous amount of research with rethinking on a number of pathogenetic concepts. Less than 25 years after the first autopsy series of AIDS patients were published and the virus responsible for AIDS was identified, satisfactory definition and classification of a number of neuropathological complications of HIV infection have been established, leading to accurate clinical radiological and biological diagnosis of the main neurological complications of the disease, which remain a major cause of disability and death in AIDS patients. Clinical and experimental studies have provided essential insight into the pathogenesis of CNS lesions and natural history of the disease. The relatively recent introduction of highly active antiretroviral therapy (HAART) in 1995-1996 has dramatically improved the course and prognosis of HIV disease. However, there remain a number of unsolved pathogenetic issues, the most puzzling of which remains the precise mechanism of neuronal damage underlying the specific HIV-related cognitive disorders (HIV dementia). In addition, although HAART has changed the course of neurological complications of HIV infection, new issues have emerged such as the lack of improvement or even paradoxical deterioration of the neurological status in treated patients. Interpretation of these latter data remains largely speculative partly because of the small number of neuropathological studies related to the beneficial consequence of this treatment.

Coma as a presenting symptom of primary HIV infection

Primary HIV infection (PHI) is symptomatic in 50-90% of patients. The diagnosis, however, is seldom made at first presentation. This is probably because of the multifaceted and unspecific manifestations, the omission to perform adequate diagnostic testing and the failure to assess risks for PHI. Meningoencephalitis has been described as a fairly common presenting condition in PHI, with nuchal rigidity, fatigue, photophobia and headache; therefore, PHI should be considered in the differential diagnosis of aseptic meningitis. We present the case of a man with acute coma and a presumptive diagnosis of viral encephalitis in whom serological testing showed HIV encephalitis during PHI.

HIV and the central nervous system

Neurological complications of HIV infection are common with clinically recognized disorders ultimately affecting between 40% and 75% of patients. The spectrum of neurological disease is broad. This article highlights the common disorders of the central nervous system associated with HIV/AIDS.

Differential CD4/CCR5 utilization, gp120 conformation, and neutralization sensitivity between envelopes from a microglia-adapted human immunodeficiency virus type 1 and its parental isolate

Human immunodeficiency virus type 1 (HIV-1) infects and induces syncytium formation in microglial cells from the central nervous system (CNS). A primary isolate (HIV-1(BORI)) was sequentially passaged in cultured microglia, and the isolate recovered (HIV-1(BORI-15)) showed high levels of fusion and replicated more efficiently in microglia (J. M. Strizki, A. V. Albright, H. Sheng, M. O'Connor, L. Perrin, and F. González-Scarano, J. Virol. 70:7654-7662, 1996). The parent and adapted viruses used CCR5 as coreceptor. Recombinant viruses demonstrated that the syncytium-inducing phenotype was associated with four amino acid differences in the V1/V2 region of the viral gp120 (J. T. C. Shieh, J. Martin, G. Baltuch, M. H. Malim, and F. González-Scarano, J. Virol. 74:693-701, 2000). We produced luciferase-reporter, env-pseudotyped viruses using plasmids containing env sequences from HIV-1(BORI), HIV-1(BORI-15), and the V1/V2 region of HIV-1(BORI-15) in the context of HIV-1(BORI) env (named rBORI, rB15, and rV1V2, respectively). The pseudotypes were used to infect cells expressing various amounts of CD4 and CCR5 on the surface. In contrast to the parent recombinant, the rB15 and rV1V2 pseudotypes retained their infectability in cells expressing low levels of CD4 independent of the levels of CCR5, and they infected cells expressing CD4 with a chimeric coreceptor containing the third extracellular loop of CCR2b in the context of CCR5 or a CCR5 Delta4 amino-terminal deletion mutant. The VH-rB15 and VH-rV1V2 recombinant viruses were more sensitive to neutralization by a panel of HIV-positive sera than was VH-rBORI. Interestingly, the CD4-induced 17b epitope on gp120 was more accessible in the rB15 and rV1V2 pseudotypes than in rBORI, even before CD4 binding, and concomitantly, the rB15 and rV1V2 pseudotypes were more sensitive to neutralization with the human 17b monoclonal antibody. Adaptation to growth in microglia--cells that have reduced expression of CD4 in comparison with other cell types--appears to be associated with changes in gp120 that modify its ability to utilize CD4 and CCR5. Changes in the availability of the 17b epitope indicate that these affect conformation. These results imply that the process of adaptation to certain tissue types such as the CNS directly affects the interaction of HIV-1 envelope glycoproteins with cell surface components and with humoral immune responses.

Acute retrovirus syndrome among prospectively identified homosexual men with incident HIV infection in Brazil. Projecto Praça Onze Study Group

BACKGROUND

Symptoms associated with HIV infection are common among HIV seroconverters, but the acute retroviral syndrome (ARS) is a diagnostic challenge because of the absence of a sensitive and specific case definition. We conducted an analysis of HIV seroconverters in Projeto Praça Onze, a HIVNET HIV seroincidence study among homosexual men in Rio de Janeiro.

METHODS

Information from study subjects enrolled in Projeto Praça Onze who were documented HIV seroconverters were compared with nonseroconverters. At each semiannual study visit, participants were asked about HIV seroconversion symptoms and sexually transmitted diseases (STDs) during the preceding 6 months. All information was collected before the laboratory evaluation. A classification tree analysis was used to identify an ARS case definition, first using clinical information and then after including risk factor data for seroconversion in our cohort.

RESULTS

As of July 1998, 674 volunteers were enrolled and 34 of these seroconverted; information was available for 33 of these. Among the seroconverters, 11 (34%) denied any symptoms, and 22 (66%) reported one or more symptoms, the most common of which were fever (25% of seroconverters versus 7% of nonseroconverters; p <.01), night sweats (9% versus 2%, respectively; p =.05), incapacitating disease (ID) for >/=3 days (27% versus 7%, respectively; p <.001), and weight loss of >/=2 kg (21% versus 9%, respectively; p =.05). STDs were more common in seroconverters (gonorrhea: 9% versus 1%, respectively; p <.01 and condyloma: 9% versus 3%, respectively; p =. 08). The first case definition was ID for >3 days, fever, pharyngitis, and myalgia (seroconverters, 3 of 32, versus nonseroconverters, 2 of 640). The second case definition was was ID for >3 days, anti-core hepatitis b-positive, and age <21 years (seroconverters: 6 of 32 versus nonseroconverters 4 of 640). The sensitivity and specificity for the first and second case definitions were: 9.4%, 99.4%, and 18.8%, 99.8%, respectively.

CONCLUSIONS

Among HIV seroconverters, symptoms consistent with ARS were common. We were unable to identify a sensitive case definition that could be used as a screening tool. Although the clinical case definition was not validated, the specificity of our case definitions was high, suggesting that subjects within this HIV risk group who fulfill the case definition should be tested for HIV.

Magnetic resonance spectroscopy of the brain in neurologically asymptomatic HIV-infected patients

The CNS involvement is frequently found in human immunodeficiency virus (HIV) infection. The purpose of our study was to determine whether proton magnetic resonance spectroscopy (MRS) could detect early brain involvement in neurologically asymptomatic HIV-infected patients with normal MR imagings and to find the correlation between MRS and the immune status. We performed MRS in 30 HIV seropositive neurologically asymptomatic patients with normal MRI and compared the MRS findings with 13 controls. A statistically significant reduction in N-acetylaspartate (NAA)/creatine (Cr) and N-acetylaspartate (NAA)/choline (Cho) in both centrum semiovale (p < 0.005) and thalamic areas (p < 0.05) was found. There is no statistically significant difference as to choline (Cho)/creatine (Cr) and myoinositol (mI)/creatine (Cr) ratios in both regions. The difference of NAA/Cr was more pronounced in the white matter than in the gray matter. As for the immune status, there was a trend towards correlation between CD4 counts and NAA/Cr but devoid of statistical significance. Our results suggest that MRS is more sensitive than conventional MR imaging in detecting CNS involvement in neurologically asymptomatic HIV patients and may, therefore, be used for early detection of brain damage induced by HIV.

Neurological symptoms during primary human immunodeficiency virus (HIV) infection correlate with high levels of HIV RNA in cerebrospinal fluid

This analysis involves 22 patients with diagnosed symptomatic human immunodeficiency virus (HIV) infection. Neurologic symptoms were present in 11 patients, ranging from severe and persistent headache to clinical signs suggestive of meningitis. A strong correlation between neurological symptoms and cerebrospinal fluid (CSF) viral load was found. The mean CSF HIV ribonucleic acid (RNA) level was 4. 12 log for patients with neurological symptoms and 2.58 log for patients without neurological symptoms (P<.00001). Plasma viral load alone does not correlate or predict central nervous system (CNS) involvement. In our sample of patients, HIV RNA levels could be detected in most patients regardless of the presence of neurological symptoms. Moreover, early treatment including drugs with high levels of penetration in the CNS must be considered for patients with primary HIV infection.

Early detection of neurophysiological abnormalities in infection by human immunodeficiency virus

The human immunodeficiency virus causes serious, progressive and irreversible deterioration of the immunocompetence system and of the nervous system, so neurological pathology in infected patients is frequent (30-40%), affecting both the central and the peripheral nervous systems. There are different clinical and laboratory indicators of bad prognosis, considering the important neurotropism of the virus. This study attempts to evaluate which neurophysiological parameters are altered during the initial phases of infection by HIV. A total of 46 individuals were studied, 30 seronegative and 16 seropositive in stage A of the CDC-93 classification. Motor and sensory conduction studies were carried out on all of them on the upper and lower extremities, as well as visual, somatosensory and auditory evoked potentials and endogenous potentials, mainly P300. The analysis of the neurophysiological parameters evaluated in our series, showed alterations of the conduction velocity of the sural nerve, latency of N1 of the SSEP of median and posterior tibial nerves and P300 in the initial phases of the infection even in the absence of clinical symptomatology.

HIV and the returning expatriate

Worldwide seroprevalence of the Human Immunodeficiency Virus (HIV) was estimated at 29.4 million at the end of 1996 with 75-85% of infections in adults transmitted through sexual intercourse, and by heterosexual intercourse in more then 70%. SubSaharan Africa is currently the area most heavily affected but over the past 5 years rapid spread of the virus has occurred in Asia. No developing country is free of HIV infection and HIV infection acquired abroad now accounts for most of heterosexually acquired HIV infection presenting in the (United Kingdom) UK, accounting for 25% of new HIV cases in the UK in the year to end March 1995 and 18% in the year to end March 1996, and at least 38% of new cases in Scotland in 1996.

Primary HIV Infection

Acute human immunodeficiency virus (HIV) infection, referred to as primary HIV infection (PHI), is associated in the majority of patients with an acute retroviral syndrome presenting similarities with infectious mononucleosis and an exponential rise in viral titres. Symptoms rapidly amend and viraemia levels decline spontaneously to reach a set point at 6 months. The intensity of the acute retroviral syndrome and viraemia levels at set point are predictive of HIV disease progression. There are a number of arguments favouring initiation of treatment at the time of PHI (homogeneity of viral populations, preservation of the immune system, prevention of virus spreading) but these arguments should be weighted against parameters more difficult to evaluate such as long-term drug-associated toxicities and adherence. In clinical practice, adherence is closely linked to the patient's commitment, which is the key parameter for treatment decision.

Evidence of CNS impairment in HIV infection: clinical, neuropsychological, EEG, and MRI/MRS study

OBJECTIVES

To identify by clinical examination, EEG, MRI, and proton spectroscopy, and neuropsychological assessment the prevalence of signs of CNS involvement in patients infected with HIV, and to relate such findings to the evidence of immunosuppression.

METHODS

The design was a cross sectional analysis of a cohort of male patients with infected HIV with an AIDS defining diagnosis or low CD4 count (<350), and seropositive asymptomatic subjects, both groups being followed up in a longitudinal study. Control groups consisted of seronegative subjects from the same genitourinary medicine clinics.

RESULTS

This report sets out the cross sectional findings at the seventh visit in the longitudinal study. Patients with AIDS had more signs of neurological dysfunction, poorer performance on a neuropsychological test battery, were more likely to have an abnormal EEG, and to have abnormalities on MRI. They more often had cerebral atrophy, abnormal appearing white matter, and abnormal relaxometry and spectroscopy. There was little evidence of abnormality in seropositive people who had a CD4 count >350 compared with seronegative people from a similar background.

CONCLUSIONS

Detailed testing failed to disclose significant CNS impairment without immunosuppression in men infected with HIV. Findings from MRI and magnetic resonance spectroscopy (MRS) correlated with those of the neurological examination and neuropsychological assessment. A combination of such assessments offers a simple surrogate for studies of CNS involvement in HIV disease.

Chemokine receptor utilization by human immunodeficiency virus type 1 isolates that replicate in microglia

The role of human immunodeficiency virus (HIV) strain variability remains a key unanswered question in HIV dementia, a condition affecting around 20% of infected individuals. Several groups have shown that viruses within the central nervous system (CNS) of infected patients constitute an independently evolving subset of HIV strains. A potential explanation for the replication and sequestration of viruses within the CNS is the preferential use of certain chemokine receptors present in microglia. To determine the role of specific chemokine coreceptors in infection of adult microglial cells, we obtained a small panel of HIV type 1 brain isolates, as well as other HIV strains that replicate well in cultured microglial cells. These viruses and molecular clones of their envelopes were used in infections, in cell-to-cell fusion assays, and in the construction of pseudotypes. The results demonstrate the predominant use of CCR5, at least among the major coreceptors, with minor use of CCR3 and CXCR4 by some of the isolates or their envelope clones.

[Symptomatic primary human immunodeficiency virus infection]

Symptomatic primary human immunodeficiency virus (HIV) infection was originally defined as a mononucleosis-like syndrome, with or without lymphocytic meningitis, associated with seroconversion for HIV. However, other protean clinical manifestations have been reported, and diagnosis should be considered in patients with risk factors for HIV who experience acute infectious illness, requiring search for p24 antigenemia and development of HIV antibodies. The clinical presentation of symptomatic HIV infection could predict the subsequent disease progression. In several studies, it is associated with poor prognosis. Pathogenesis relies on the host immune response and on virologic parameters. Early antiretroviral therapy on acute HIV infection could modify the course of infection.

Neuropathology of early HIV-1 infection

Early HIV-1 invasion of the central nervous system has been demonstrated by many cerebrospinal fluid studies; however, most HIV-1 carriers remain neurologically unimpaired during the so called "asymptomatic" period lasting from seroconversion to symptomatic AIDS. Therefore, neuropathological studies in the early pre-AIDS stages are very few, and the natural history of central nervous system changes in HIV-1 infection remains poorly understood. Examination of brains of asymptomatic HIV-1 positive individuals who died accidentally and of rare cases with acute fatal encephalopathy revealing HIV infection, and comparison with experimental simian immunodeficiency virus and feline immunodeficiency virus infections suggest that, invasion of the CNS by HIV-1 occurs at the time of primary infection and induces an immunological process in the central nervous system. This includes an inflammatory T-cell reaction with vasculitis and leptomeningitis, and immune activation of brain parenchyma with increased number of microglial cells, upregulation of major histocompatibility complex class II antigens and local production of cytokines. Myelin pallor and gliosis of the white matter are usually found and are likely to be the consequence of opening of the blood brain barrier due to vasculitis; direct damage to oligodendrocytes by cytokines may also interfere. These white matter changes may explain, at least partly, the early cerebral atrophy observed, by magnetic resonance imaging, in asymptomatic HIV-1 carriers. In contrast, cortical damage seems to be a late event in the course of HIV-1 infection. There is no significant neuronal loss at the early stages of the disease, no accompanying increase in glial fibrillary acid protein staining in the cortex, and only exceptional neuronal apoptosis. Although HIV-1 proviral DNA may be demonstrated in a number of brains, viral replication remains very low during the asymptomatic stage of HIV-1 infection. This makes it likely that, although opening of the blood brain barrier may facilitate viral entry into the brain, specific immune responses including both neutralising antibodies and cytotoxic T-lymphocytes, continuously inhibits viral replication at that stage.

Neurophysiological assessment of peripheral nerve and spinal cord function in asymptomatic HIV-1 infection: results from the UCMSM/Medical Research Council neurology cohort

As part of the Medical Research Council prospective study of the neurological complications of HIV infection, neurophysiological tests of spinal cord and peripheral nerve function were recorded in a cohort of homosexual or bisexual men. The studies included motor and sensory nerve conduction studies, vibration perception thresholds, somatosensory evoked potentials and motor evoked potentials elicited by magnetic stimulation. The results were compared with markers of immune function. The findings from 114 volunteers were analysed in a cross-sectional study. Fifty-nine were HIV-seropositive but asymptomatic, 26 had progressed to the symptomatic stages of HIV disease and 29 were persistently HIV-seronegative. There was some evidence of a mild sensory axonopathy in the symptomatic HIV-seropositive group. No differences were detected between the asymptomatic HIV-seropositive group and the HIV-seronegative comparison group. There were no consistently significant correlations between the neurophysiological measurements and CD4 counts and beta 2-microglobulin levels. On repeated testing, there was no evidence of a trend towards deterioration over a mean period of approximately 3 years in 36 HIV-seropositive subjects who remained asymptomatic compared with 22 HIV-seronegatives. These findings have failed to demonstrate neurophysiological evidence of spinal cord or peripheral nerve dysfunction in the asymptomatic stages of HIV infection.

Depression, HIV dementia, delirium, posttraumatic stress disorder (or all of the above)

A 29-year-old single Puerto Rican woman with AIDS was admitted to the Medical Service for pneumonia, seen by the Psychiatric Consultation Service, an eventually transferred to the Inpatient Psychiatric Unit with several possible psychiatric diagnoses including major depression, HIV dementia, delirium, and posttraumatic stress disorder. These possibly coexisting and interacting syndromes are discussed by three psychiatrists, one of whom is also a board-certified neurologist. This case illustrates the combined contribution of organic and psychological factor to complex behavioral disorders, which are increasingly common in HIV infection.