Neurological disorders in HIV in Africa: a review

Unravelling the triad of neuroinvasion, neurodissemination, and neuroinflammation of human immunodeficiency virus type 1 in the central nervous system

Since the identification of human immunodeficiency virus type 1 (HIV-1) in 1983, many improvements have been made to control viral replication in the peripheral blood and to treat opportunistic infections. This has increased life expectancy but also the incidence of age-related central nervous system (CNS) disorders and HIV-associated neurodegeneration/neurocognitive impairment and depression collectively referred to as HIV-associated neurocognitive disorders (HAND). HAND encompasses a spectrum of different clinical presentations ranging from milder forms such as asymptomatic neurocognitive impairment or mild neurocognitive disorder to a severe HIV-associated dementia (HAD). Although control of viral replication and suppression of plasma viral load with combination antiretroviral therapy has reduced the incidence of HAD, it has not reversed milder forms of HAND. The objective of this review, is to describe the mechanisms by which HIV-1 invades and disseminates in the CNS, a crucial event leading to HAND. The review will present the evidence that underlies the relationship between HIV infection and HAND. Additionally, recent findings explaining the role of neuroinflammation in the pathogenesis of HAND will be discussed, along with prospects for treatment and control.

Mortality and associated factors among people living with HIV admitted at a tertiary-care hospital in Uganda: a cross-sectional study

BACKGROUND

Hospital admission outcomes for people living with HIV (PLHIV) in resource-limited settings are understudied. We describe in-hospital mortality and associated clinical-demographic factors among PLHIV admitted at a tertiary-level public hospital in Uganda.

METHODS

We performed a cross-sectional analysis of routinely collected data for PLHIV admitted at Kiruddu National Referral Hospital between March 2020 and March 2023. We estimated the proportion of PLHIV who had died during hospitalization and performed logistic regression modelling to identify predictors of mortality.

RESULTS

Of the 5,827 hospitalized PLHIV, the median age was 39 years (interquartile range [IQR] 31-49) and 3,293 (56.51%) were female. The median CD4 + cell count was 109 cells/µL (IQR 25-343). At admission, 3,710 (63.67%) were active on antiretroviral therapy (ART); 1,144 (19.63%) had interrupted ART > 3 months and 973 (16.70%) were ART naïve. In-hospital mortality was 26% (1,524) with a median time-to-death of 3 days (IQR 1-7). Factors associated with mortality (with adjusted odds ratios) included ART interruption, 1.33, 95% confidence intervals (CI) 1.13-1.57, p 0.001; CD4 + counts ≤ 200 cells/µL 1.59, 95%CI 1.33-1.91, p < 0.001; undocumented CD4 + cell count status 2.08, 95%CI 1.73-2.50, p < 0.001; impaired function status 7.35, 95%CI 6.42-8.41, p < 0.001; COVID-19 1.70, 95%CI 1.22-2.37, p 0.002; liver disease 1.77, 95%CI 1.36-2.30, p < 0.001; co-infections 1.53, 95%CI 1.32-1.78, p < 0.001; home address > 20 km from hospital 1.23, 95%CI 1.04-1.46, p 0.014; hospital readmission 0.7, 95%CI 0.56-0.88, p 0.002; chronic lung disease 0.62, 95%CI 0.41-0.92, p 0.019; and neurologic disease 0.46, 95%CI 0.32-0.68, p < 0.001.

CONCLUSION

One in four admitted PLHIV die during hospitalization. Identification of risk factors (such as ART interruption, function impairment, low/undocumented CD4 + cell count), early diagnosis and treatment of co-infections and liver disease could improve outcomes.

Management Practice and Clinical Outcomes of Dementia in Sub-Saharan Africa: A Systematic Review

Background

Dementia is a severe neurodegenerative disorder and it is a group of acquired symptoms associated with impaired cognitive functions. In low-income settings particularly in Sub-Saharan Africa (SSA), it is often seen as part of normal aging. Environmental, behavioral, and lifestyle interventions have the potential to alter the disease course of dementia.

Objective

This study is aimed to synthesize the literature/evidence(s) on the management practice and treatment outcomes of dementia in SSA.

Method

Comprehensive literature was searched in PubMed database, Cochrane Library, and Google Scholar. Eligibility has been set, and based on the criteria, initially, a total of 442 results were obtained, and from those around 183 articles were duplicated. After examining titles and abstracts of records 26 articles were identified. Finally, five randomized clinical trials (RCT) and three prospective cohort studies that were reported on the management practice and treatment outcome of dementia in SSA were eligible for analysis. RCT and prospective cohort studies were used to strengthen the quality of evidence. The quality of the included RCT studies was assessed by using the Cochrane Risk of Bias Tool.

Result

A total of 2781 patient data were included in the final analysis. Of these, 2354 patients were obtained from 5 RCTs and 427 patients from 3 prospective cohort studies, which were conducted in SSA countries. RCT studies were done on the feasibility and clinical effectiveness of cognitive stimulation therapy (CST) showed improvements in language memory domains and physical health. In addition, studies that focus on the management of human immunodeficiency virus-associated dementia (HIVAD) were reported to improve neurocognitively.

Conclusion

CST is applicable in low-resource settings and it shows improvements in cognitive function and quality of life. Early initiation of combination antiretroviral therapy in resource-limited settings has been associated with improvement in the cognitive function of HIVAD.

Epigenome-Wide Meta-Analysis Reveals Differential DNA Methylation Associated With Estimated Glomerular Filtration Rate Among African American Men With HIV

Introduction

People with HIV (PWH) of African ancestry have faster decline of kidney function and faster progression to end-stage renal disease than PWH of European ancestry. DNA methylation have been associated with kidney function in the general population, however, their relationships are unclear for PWH of African ancestry.

Methods

We performed epigenome-wide association studies (EWAS) of estimated glomerular filtration rate (eGFR) among PWH of African ancestry in 2 subsets of the Veterans Aging Cohort Study cohort (N = 885), followed by a meta-analysis to combine the results. Replication was conducted among independent African American samples without HIV.

Results

DNA methylation sites cg17944885 near Zinc Finger Family Member 788 (ZNF788) and Zinc Finger Protein 20 (ZNF20), and cg06930757 in SHANK1 were significantly associated with eGFR among PWH of African ancestry (false discovery rate < 0.05). DNA methylation site cg17944885 was also associated with eGFR among different populations including African Americans without HIV.

Conclusions

Our study attempted to address an important gap in the literature and to understand the role of DNA methylation in renal diseases in PWH of African ancestry. Replication of cg17944885 among different populations suggests there may be a common pathway for renal diseases progression among PWH and people without HIV, and across different ancestral groups. Our results suggest that genes ZNF788/ZNF20 and SHANK1 could be involved in a pathway linking DNA methylation to renal diseases among PWH and are worth further investigation.

Association of High Ratio of CSF/Plasma HIV-1 RNA with Central Nervous System Co-Infection in HIV-1-Positive Treatment-Naive Patients

Cerebrospinal fluid (CSF) human immunodeficiency virus-1 (HIV-1) ribonucleic acid (RNA) at higher levels than in plasma has been observed in HIV-1-positive patients and defined as CSF/plasma discordance or CSF escape. Discordance is particularly seen in untreated patients with antiretroviral agents. Quantitative data regarding its association with blood−brain barrier (BBB) damage and intracranial co-infection with other pathogens are limited. Therefore, we used the CSF to plasma HIV-1 RNA ratio (HRR) to determine its relation to central nervous system (CNS) co-infection in HIV-1-positive treatment-naïve individuals. We retrospectively recruited the subjects with HIV-1-positive and potential neurological deficits. A lumbar puncture was performed before the antiretroviral therapy. The paired CSF/plasma HIV-1 RNA samples were analyzed. Univariate and multivariate logistic regression models and multiple spine regression analyses were performed to assess the association between the HRR and CNS co-infection. A total of 195 patients with 78% males (median age: 49 years) were included in this study, of whom 98 (50.2%) had CNS co-infection with other pathogens. The receiver-operating characteristic curve analysis showed that the optimal cutoff value for the HRR to predict the CNS co-infection was 1.00. Higher HRR (≥1) was significantly associated with tuberculous meningitis (OR 6.50, 95% CI 2.08−20.25, p = 0.001), cryptococcus meningitis (OR 7.58, 95% CI 2.10−27.32, p = 0.001), and multiple co-infection (OR 4.04, 95% CI 1.02−16.04, p = 0.047). Higher HRR (≥1) (OR 3.01, 95% CI 1.09−8.73, p = 0.032) was independently associated with the CNS co-infection after adjusting for covariates. No significant nonlinear association was found between the HRR and CNS co-infection in the multivariate spline regression (p > 0.05) and a positive relationship was found between the HRR and CNS co-infection when the HRR was ≥0.78. Higher HRR was associated with an increased risk of CNS co-infection in HIV-1-positive patients. The relationship between the HRR and CNS co-infection may be related to the BBB disturbance and warrants further investigation with a large, longitudinal cohort.

Neuroimmunology of CNS HIV Infection: A Narrative Review

This short review provides an overview of the interactions of human immunodeficiency virus type 1 (HIV), immune and inflammatory reactions, and CNS injury over the course of infection. Systemic infection is the overall driver of disease and serves as the “platform” for eventual CNS injury, setting the level of immune dysfunction and providing both the HIV seeding and immune-inflammatory responses to the CNS. These systemic processes determine the timing of and vulnerability to HIV-related neuronal injury which occurs in a separate “compartment” with features that parallel their systemic counterparts but also evolve independently. Direct CNS HIV infection, along with opportunistic infections, can have profound neurological consequences for the infected individual. HIV-related CNS morbidities are of worldwide importance but are enhanced by the particular epidemiological, socioeconomic and environmental factors that heighten the impact of HIV infection in Africa.

Post-Infectious Autoimmunity in the Central (CNS) and Peripheral (PNS) Nervous Systems: An African Perspective

The direct impact and sequelae of infections in children and adults result in significant morbidity and mortality especially when they involve the central (CNS) or peripheral nervous system (PNS). The historical understanding of the pathophysiology has been mostly focused on the direct impact of the various pathogens through neural tissue invasion. However, with the better understanding of neuroimmunology, there is a rapidly growing realization of the contribution of the innate and adaptive host immune responses in the pathogenesis of many CNS and PNS diseases. The balance between the protective and pathologic sequelae of immunity is fragile and can easily be tipped towards harm for the host. The matter of immune privilege and surveillance of the CNS/PNS compartments and the role of the blood-brain barrier (BBB) and blood nerve barrier (BNB) makes this even more complex. Our understanding of the pathogenesis of many post-infectious manifestations of various microbial agents remains elusive, especially in the diverse African setting. Our exploration and better understanding of the neuroimmunology of some of the infectious diseases that we encounter in the continent will go a long way into helping us to improve their management and therefore lessen the burden. Africa is diverse and uniquely poised because of the mix of the classic, well described, autoimmune disease entities and the specifically "tropical" conditions. This review explores the current understanding of some of the para- and post-infectious autoimmune manifestations of CNS and PNS diseases in the African context. We highlight the clinical presentations, diagnosis and treatment of these neurological disorders and underscore the knowledge gaps and perspectives for future research using disease models of conditions that we see in the continent, some of which are not uniquely African and, where relevant, include discussion of the proposed mechanisms underlying pathogen-induced autoimmunity. This review covers the following conditions as models and highlight those in which a relationship with COVID-19 infection has been reported: a) Acute Necrotizing Encephalopathy; b) Measles-associated encephalopathies; c) Human Immunodeficiency Virus (HIV) neuroimmune disorders, and particularly the difficulties associated with classical post-infectious autoimmune disorders such as the Guillain-Barré syndrome in the context of HIV and other infections. Finally, we describe NMDA-R encephalitis, which can be post-HSV encephalitis, summarise other antibody-mediated CNS diseases and describe myasthenia gravis as the classic antibody-mediated disease but with special features in Africa.

Neurological disorders in Northern Tanzania: A 6-year prospective hospital-based case series

Background

The burden of neurological disorders is large and altered by the HIV epidemic.

Objectives

We describe the pattern of neurological disorders and their association with HIV infection in adult patients attending a consultant hospital in Northern Tanzania.

Methods

In this prospective cross-sectional study, we collected data on adult neurological referrals over a 6-year period between 2007-13. The odds of HIV infection, across neurological categories adjusted for age and sex, was calculated.

Results

Of 2037 participants, 54.8% were male and 45.2% were female. The median age of participants was 43 years. The results for HIV screening were available for 992/2037 (48.7%) patients, of whom 306 (30.8%) were seropositive. The most frequent neurological disorders were cerebrovascular disease (19.9%), paraplegia (13.6%), and peripheral neuropathies (8%). Taken together CNS infection accounted for 278/2037 (13.6%). The adjusted odds (aOR) of HIV infection was highest amongst infections; brain abscesses (aOR 107, 95% CI 35.1-470.4) and meningitis/encephalitis (aOR 40.1, 95% CI 13.6-172.9), but also raised in cerebrovascular disease, paraplegia, peripheral neuropathies, cranial nerve palsies, seizures, cerebllar disorders, movement disorders, motor neuron disease and headache.

Conclusion

The main pattern of neurological disorders in Northern Tanzania is presented. The odds of HIV infection was highest in CNS infections and in a wide range of non-communicable neurological disorders.

The Interplay Between Neuroinfections, the Immune System and Neurological Disorders: A Focus on Africa

Neurological disorders related to neuroinfections are highly prevalent in Sub-Saharan Africa (SSA), constituting a major cause of disability and economic burden for patients and society. These include epilepsy, dementia, motor neuron diseases, headache disorders, sleep disorders, and peripheral neuropathy. The highest prevalence of human immunodeficiency virus (HIV) is in SSA. Consequently, there is a high prevalence of neurological disorders associated with HIV infection such as HIV-associated neurocognitive disorders, motor disorders, chronic headaches, and peripheral neuropathy in the region. The pathogenesis of these neurological disorders involves the direct role of the virus, some antiretroviral treatments, and the dysregulated immune system. Furthermore, the high prevalence of epilepsy in SSA (mainly due to perinatal causes) is exacerbated by infections such as toxoplasmosis, neurocysticercosis, onchocerciasis, malaria, bacterial meningitis, tuberculosis, and the immune reactions they elicit. Sleep disorders are another common problem in the region and have been associated with infectious diseases such as human African trypanosomiasis and HIV and involve the activation of the immune system. While most headache disorders are due to benign primary headaches, some secondary headaches are caused by infections (meningitis, encephalitis, brain abscess). HIV and neurosyphilis, both common in SSA, can trigger long-standing immune activation in the central nervous system (CNS) potentially resulting in dementia. Despite the progress achieved in preventing diseases from the poliovirus and retroviruses, these microbes may cause motor neuron diseases in SSA. The immune mechanisms involved in these neurological disorders include increased cytokine levels, immune cells infiltration into the CNS, and autoantibodies. This review focuses on the major neurological disorders relevant to Africa and neuroinfections highly prevalent in SSA, describes the interplay between neuroinfections, immune system, neuroinflammation, and neurological disorders, and how understanding this can be exploited for the development of novel diagnostics and therapeutics for improved patient care.

Changing Patterns of Lymphoma in the Antiretroviral Therapy Era in Johannesburg, South Africa

BACKGROUND

South Africa has a high HIV prevalence, which associates with an increased risk of lymphoma. Antiretroviral therapy (ART) became accessible in 2004, but the program has substantially expanded. Changes in lymphoma patterns are documented in high-income countries after wide-scale ART including declining high-grade B-cell non-Hodgkin lymphomas (HG B-NHLs), particularly diffuse large B-cell lymphoma, and increased Hodgkin lymphoma (HL). There are limited data from Africa. This study aimed to compare HG B-NHL characteristics in the early (2007) and later (2017) ART era.

METHODS

All incident lymphomas at the National Health Laboratory Service, Johannesburg, were identified using the laboratory information system, and data were collected for each patient.

RESULTS

The total number of lymphoma cases increased from 397 (2007) to 582 (2017). This was associated with improved lymphoma classification and patient referral for oncological care. HG B-NHL remained the most diagnosed lymphoma subtype in 2017 comprising 70% of HIV-associated lymphomas, followed by HL (24%). Diffuse large B-cell lymphoma comprised 65% of all HG B-NHLs and 45% of all lymphomas in people with HIV in 2017. Significantly more patients were on ART in 2017, with improvements in virological control documented. Despite this, 47.6% of patients were not virologically suppressed, and 37.5% of patients were ART-naive at time of diagnosis in 2017. Immunological reconstitution was suboptimal, which may reflect late initiation of ART.

CONCLUSION

Public health initiatives to initiate ART as early as possible and to retain patients in ART programs may assist in decreasing the number of HIV-associated lymphomas in our setting.

High prevalence of epilepsy in Northern Rwanda: Exploring gender differences

INTRODUCTION

In sub-Saharan Africa (SSA), the prevalence of lifetime epilepsy varies widely between subregions and is higher in rural compared to urban regions. Observed versus expected numbers of patients with epilepsy (PwE) in the northern province of Rwanda did not match the prevalence of 49‰ reported in 2005 in Rwanda. We report a confirmatory prevalence study focused on gender-specific observations.

METHODS

A cross-sectional door-to-door approach was used in three rural villages. First, epilepsy screening using the Kinyarwanda version of the Limoges questionnaire was performed. Second, confirmation of epilepsy diagnosis was completed by trained physicians.

RESULTS

In total, 2681 persons (56.14% female) were screened. Of 168 positively screened, 128 persons were diagnosed with epilepsy confirming the prevalence of lifetime epilepsy of 47.7‰ (CI 39.8-56.8). The diagnosis gap was 62.5% with 80 newly diagnosed. The overall female:male ratio was 1.61:1.00. A male preponderance below 9 years of age inverted to a female preponderance above 20 years of age. Female PwE had an older age at first seizure, reported different reasons for not seeking care, and differed from male PwE in possible etiology. For previously diagnosed PwE, the treatment gap was more than 77%.

CONCLUSION

A high prevalence in rural areas was confirmed, with an observed female/male ratio among the highest of published door-to-door surveys in SSA. Gender differences in associated co-morbidities and age at first seizure warrant future research of underlying etiologies and possible survival bias. A better understanding and focus on gender-associated care-seeking patterns, education, and specific needs are recommended.

Central Nervous System Tuberculosis (CNS-TB) in treated HIV-infected adults in Tikur Anbessa Specialized Hospital, Ethiopia: A cross sectional study

BACKGROUND

Central nervous system (CNS) tuberculosis (TB) is a calamitous infection with high rates of morbidity and mortality. Underlying HIV infection often increases susceptibility for acquiring TB and also complicates TB treatment. The study objectives were to assess the burden of CNS TB and associated factors in treatment experienced HIV infected adults.

METHODS

A single-center observational cross-sectional study was conducted between December 2019 and June 2020. Both descriptive and analytical statistics were used to analyze the data.

RESULTS

Ninety-five HIV infected adults with presumptive TB-HIV co-infection on combination antiretroviral therapy for median of 144 months were assessed. The mean age was 40.8 years (1SD = 12.4). Male to female ratio was 1:2. The prevalence of CNS tuberculosis was 56.8% (TB menigitis 53.7%, tuberculoma 2.1%, and spinal TB 1.1%). Patients with CNS TB were younger compared to those with extra CNS TB (38.6 vs. 43.6 years, p = 0.04). A higher proportion of patients with CNS TB had undetectable HIV RNA compared to those with extra CNS TB (55.8% vs. 36.8% p = 0.04). In multivariate regression analysis, advanced disease stages, deferred cotrimoxazole preventive therapy (CPT), and deferred INH preventive therapy (IPT) were found to be independent predictors of CNS TB. Although not statistically significant, the trend for HIV-associated cognitive decline was higher in the group with CNS TB.

CONCLUSION

The prevalence of CNS TB was higher among HIV-infected adults with TB-HIV co-infection. TB meningitis was the most common type of CNS TB. Advanced disease stages, deferred CPT, and deferred IPT were predictors of CNS tuberculosis. Although statistically not-significant, the trend for HAND was higher in the group diagnosed with CNS tuberculosis.

HIV-Associated CD8 Encephalitis: A UK Case Series and Review of Histopathologically Confirmed Cases

HIV-associated CD8-encephalitis (HIV-CD8E) is a severe inflammatory disorder dominated by infiltration of the brain by CD8+ T-lymphocytes. It occurs in people with HIV, typically when the virus is apparently well-controlled by antiretroviral treatment (ART). HIV-CD8E presents with symptoms and signs related to marked cerebral inflammation and swelling, and can lead to coma and death unless treated promptly with corticosteroids. Risk events such as intercurrent infection, antiretroviral therapy interruption, immune reconstitution inflammatory syndrome (IRIS) after starting ART, and concomitant associations such as cerebrospinal fluid (CSF) HIV viral escape have been identified, but the pathogenesis of the disorder is not known. We present the largest case series of HIV-CD8E to date (n = 23), representing histopathologically confirmed cases in the UK. We also summarize the global literature representing all previously published cases with histopathological confirmation (n = 30). A new variant of HIV-CD8E is described, occurring on a background of HIV encephalitis (HIVE).Together these series, totalling 53 patients, provide new insights. CSF HIV viral escape was a frequent finding in HIV-CD8E occurring in 68% of those with CSF available and tested; ART interruption and IRIS were important, both occurring in 27%. Black ethnicity appeared to be a key risk factor; all but two UK cases were African, as were the majority of the previously published cases in which ethnicity was stated. We discuss potential pathogenic mechanisms, but there is no unifying explanation over all the HIV-CD8E scenarios.

Diagnosing peripheral neuropathy in South-East Asia: A focus on diabetic neuropathy

Burning and stabbing pain in the feet and lower limbs can have a significant impact on the activities of daily living, including walking, climbing stairs and sleeping. Peripheral neuropathy in particular is often misdiagnosed or underdiagnosed because of a lack of awareness amongst both patients and physicians. Furthermore, crude screening tools, such as the 10-g monofilament, only detect advanced neuropathy and a normal test will lead to false reassurance of those with small fiber mediated painful neuropathy. The underestimation of peripheral neuropathy is highly prevalent in the South-East Asia region due to a lack of consensus guidance on routine screening and diagnostic pathways. Although neuropathy as a result of diabetes is the most common cause in the region, other causes due to infections (human immunodeficiency virus, hepatitis B or C virus), chronic inflammatory demyelinating polyneuropathy, drug-induced neuropathy (cancer chemotherapy, antiretrovirals and antituberculous drugs) and vitamin deficiencies (vitamin B1 , B6 , B12 , D) should be actively excluded.