Cryptococcal Antigenemia in Human Immunodeficiency Virus Antiretroviral Therapy-Experienced Ugandans With Virologic Failure

Re-estimation of the burden of serious fungal diseases in Uganda

Background

It is of utmost importance to monitor any change in the epidemiology of fungal diseases that may arise from a change in the number of the at-risk population or the availability of local data.

Objective

We sought to update the 2015 publication on the incidence and prevalence of serious fungal diseases in Uganda.

Methods

Using the Leading International Fungal Education methodology, we reviewed published data on fungal diseases and drivers of fungal diseases in Uganda. Regional or global data were used where there were no Ugandan data.

Results

With a population of ~45 million, we estimate the annual burden of serious fungal diseases at 4,099,357 cases (about 9%). We estimated the burden of candidiasis as follows: recurrent Candida vaginitis (656,340 cases), oral candidiasis (29,057 cases), and esophageal candidiasis (74,686 cases) in HIV-infected people. Cryptococcal meningitis annual incidence is estimated at 5553 cases, Pneumocystis pneumonia at 4604 cases in adults and 2100 cases in children. For aspergillosis syndromes, invasive aspergillosis annual incidence (3607 cases), chronic pulmonary aspergillosis (26,765 annual cases and 63,574 5-year-period prevalent cases), and prevalence of allergic bronchopulmonary aspergillosis at 75,931 cases, and severe asthma with fungal sensitization at 100,228 cases. Tinea capitis is common with 3,047,989 prevalent cases. For other mycoses, we estimate the annual incidence of histoplasmosis to be 646 cases and mucormycosis at 9 cases.

Conclusion

Serious fungal diseases affect nearly 9% of Ugandans every year. Tuberculosis and HIV remain the most important predisposition to acute fungal infection necessitating accelerated preventive, diagnostic, and therapeutic interventions for the management of these diseases.

Immunization with a heat-killed prm1 deletion strain protects the host from Cryptococcus neoformans infection

Systemic infection with Cryptococcus neoformans, a dangerous and contagious pathogen found throughout the world, frequently results in lethal cryptococcal pneumonia and meningoencephalitis, and no effective treatments and vaccination of cryptococcosis are available. Here, we describe Prm1, a novel regulator of C. neoformans virulence. C. neoformans prm1Δ cells exhibit extreme sensitivity to various environmental stress conditions. Furthermore, prm1Δ cells show deficiencies in the biosynthesis of chitosan and mannoprotein, which in turn result in impairment of cell wall integrity. Treatment of mice with heat-killed prm1Δ cells was found to facilitate the host immunological defence against infection with wild-type C. neoformans. Further investigation demonstrated that prm1Δ cells strongly promote pulmonary production of interferon-γ, leading to activation of macrophage M1 differentiation and inhibition of M2 polarization. Therefore, our findings suggest that C. neoformans Prm1 may be a viable target for the development of anti-cryptococcosis medications and, cells lacking Prm1 represent a promising candidate for a vaccine.

Cryptococcal meningitis

Cryptococcus neoformans and Cryptococcus gattii species complexes cause meningoencephalitis with high fatality rates and considerable morbidity, particularly in persons with deficient T cell-mediated immunity, most commonly affecting people living with HIV. Whereas the global incidence of HIV-associated cryptococcal meningitis (HIV-CM) has decreased over the past decade, cryptococcosis still accounts for one in five AIDS-related deaths globally due to the persistent burden of advanced HIV disease. Moreover, mortality remains high (~50%) in low-resource settings. The armamentarium to decrease cryptococcosis-associated mortality is expanding: cryptococcal antigen screening in the serum and pre-emptive azole therapy for cryptococcal antigenaemia are well established, whereas enhanced pre-emptive combination treatment regimens to improve survival of persons with cryptococcal antigenaemia are in clinical trials. Short courses (≤7 days) of amphotericin-based therapy combined with flucytosine are currently the preferred options for induction therapy of cryptococcal meningitis. Whether short-course induction regimens improve long-term morbidity such as depression, reduced neurocognitive performance and physical disability among survivors is the subject of further study. Here, we discuss underlying immunology, changing epidemiology, and updates on the management of cryptococcal meningitis with emphasis on HIV-associated disease.

Implementation of point-of-care testing and prevalence of cryptococcal antigenaemia among patients with advanced HIV disease in Mumbai, India

OBJECTIVES

To describe the implementation of screening for cryptococcal antigenaemia by point-of-care (POC) serum cryptococcal antigen (CrAg) lateral flow assay, measure the prevalence and factors associated with serum cryptococcal antigenaemia in the routine programmatic setting.

DESIGN

Cross-sectional study.

SETTING

Seventeen publicly funded antiretroviral therapy (ART) centres in Mumbai, India.

PARTICIPANTS

Serum CrAg screening was offered to all adolescents (>10 years of age) and adults with advanced HIV disease (AHD) (CD4 <200 cells/mm3 or with WHO clinical stage III/IV) regardless of symptoms of cryptococcal meningitis.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was to describe the implementation of serum CrAg screening and secondary outcome was to measure the prevalence of serum cryptococcal antigenaemia and its risk factors.

RESULTS

A total of 2715 patients with AHD were tested for serum CrAg by POC assay. Of these, 25 (0.9%) had a CrAg positive result. Among CrAg-positive patients, only one had symptoms. Serum CrAg positivity was 3.6% (6/169) and 1.6% (6/520) among those presenting with CD4 <100 cells/mm3 in the treatment naïve and treatment experienced group, respectively. On multivariable analysis, CD4 count <100 cells/mm3 (OR: 2.3, 95% CI 1.01 to 5.3; p=0.05) and people living with HIV who were treatment naïve (OR: 2.5, 95% CI 1.04 to 6.0; p=0.04) were significantly associated with a positive serum CrAg result. Lumbar puncture was obtained in 20/25 patients within 4 days (range: 1-4 days) of positive serum CrAg result and one person was confirmed to have meningitis. All serum CrAg-positive patients who had a negative cerebrospinal fluid CrAg were offered pre-emptive therapy.

CONCLUSIONS

Implementation of a POC CrAg assay was possible with existing ART centre staff. Initiation of pre-emptive therapy and management of cryptococcal antigenaemia are operationally feasible at ART centres. The Indian National AIDS Control Programme may consider reflexive CrAg screening of all AHD patients with CD4 <100 cells/mm3.

Cryptococcal Antigenemia in Advanced Human Immunodeficiency Virus Disease: Pathophysiology, Epidemiology, and Clinical Implications

Cryptococcal antigen (CrAg) is detectable in blood prior to the onset of symptomatic cryptococcal meningitis (CM), a leading cause of death among people with advanced human immunodeficiency virus (HIV) disease globally. Highly sensitive assays can detect CrAg in blood, and screening people with HIV with low CD4 counts, followed by preemptive antifungal treatment, is recommended and widely implemented as part of a global strategy to prevent CM and end cryptococcal-related deaths. Cryptococcal antigenemia encompasses a spectrum of conditions from preclinical asymptomatic infection (cerebrospinal fluid [CSF] CrAg-negative) through subclinical (CSF CrAg-positive without overt meningism) to clinical symptomatic cryptococcal disease, usually manifesting as CM. In this review, we summarize current understanding of the pathophysiology, risk factors for, and clinical implications of cryptococcal antigenemia within this spectrum. We also provide an update on global prevalence, recommended screening and treatment strategies, and future considerations for improving outcomes among patients with cryptococcal antigenemia.

The global burden of HIV-associated cryptococcal infection in adults in 2020: a modelling analysis

BACKGROUND

Cryptococcal meningitis is the most common cause of meningitis in adults living with HIV in sub-Saharan Africa. The estimates of national, regional, and global burden of cryptococcal meningitis are essential to guide prevention strategies and determine needs for diagnostic tests and treatments. We present a 2020 estimate of the global burden of HIV-associated cryptococcal infection (antigenaemia), cryptococcal meningitis, and cryptococcal-associated deaths.

METHODS

We defined advanced HIV disease as adults with a CD4 count of less than 200 cells/μL, as this group is at highest risk for cryptococcosis. We used UNAIDS estimates (2019-20) and population-based HIV impact assessment surveys (2016-18) to estimate the number of adults with CD4 counts of less than 200 cells/μL at risk for cryptococcosis, by country and region. Secondly, we summarised cryptococcal antigenaemia prevalence in those with a CD4 count of less than 200 cells/μL by reviewing published literature. Thereafter, we calculated the number of cryptococcal antigen (CrAg)-positive people in each country and region by multiplying the number with advanced HIV disease at risk for cryptococcal infection by the cryptococcal antigenaemia prevalence of the respective country or region. We estimated progression from cryptococcal antigenaemia to meningitis or death based on estimates from the published literature.

FINDINGS

We estimated that there were 4·3 million (IQR 3·0-4·8) adults with HIV and CD4 counts of less than 200 cells/μL globally in 2020. We calculated a mean global cryptococcal antigenaemia prevalence of 4·4% (95% CI 1·6-7·4) among HIV-positive people with CD4 counts of less than 200 cells/μL, corresponding to 179 000 cases (IQR 133 000-219 000) of cryptococcal antigenaemia globally in 2020. Annually, we estimated that there are 152 000 cases (111 000-185 000) of cryptococcal meningitis, resulting in 112 000 cryptococcal-related deaths (79 000-134 000). Globally, cryptococcal disease accounts for 19% (13-24) of AIDS-related mortality.

INTERPRETATION

Despite a reduction in the estimated absolute global burden of HIV-associated cryptococcal meningitis compared with 2014, likely to be due to antiretroviral therapy expansion, cryptococcal disease still accounts for 19% of AIDS-related deaths, similar to 2014 estimates. To end cryptococcal meningitis deaths by 2030, cryptococcal diagnostics, meningitis treatments, and implementation of preventive screening are urgently needed.

FUNDING

None.

Comparative miRNA transcriptomics of macaques and mice reveals MYOC is an inhibitor for Cryptococcus neoformans invasion into the brain

Cryptococcal meningoencephalitis (CM) is emerging as an infection in HIV/AIDS patients shifted from primarily ART­naive to ART-experienced individuals, as well as patients with COVID-19 and immunocompetent hosts. This fungal infection is mainly caused by the opportunistic human pathogen Cryptococcus neoformans. Brain or central nervous system (CNS) dissemination is the deadliest process for this disease; however, mechanisms underlying this process have yet to be elucidated. Moreover, illustrations of clinically relevant responses in cryptococcosis are currently limited due to the low availability of clinical samples. In this study, to explore the clinically relevant responses during C. neoformans infection, macaque and mouse infection models were employed and miRNA-mRNA transcriptomes were performed and combined, which revealed cytoskeleton, a major feature of HIV/AIDS patients, was a centric pathway regulated in both infection models. Notably, assays of clinical immune cells confirmed an enhanced macrophage “Trojan Horse” in patients with HIV/AIDS, which could be shut down by cytoskeleton inhibitors. Furthermore, myocilin, encoded by MYOC, was found to be a novel enhancer for the macrophage “Trojan Horse,” and an enhanced fungal burden was achieved in the brains of MYOC-transgenic mice. Taken together, the findings from this study reveal fundamental roles of the cytoskeleton and MYOC in fungal CNS dissemination, which not only helps to understand the high prevalence of CM in HIV/AIDS but also facilitates the development of novel therapeutics for meningoencephalitis caused by C. neoformans and other pathogenic microorganisms.

Cryptococcal and Histoplasma Antigen Screening among People With HIV in Ghana and Comparative Analysis of OIDx Histoplasma Lateral Flow Assay and IMMY Histoplasma Enzyme Immunoassay

Background

Cryptococcal meningitis (CM) and disseminated histoplasmosis (DH) are common in people with HIV (PWH) and diagnosed by detecting cryptococcal antigen (CrAg) and Histoplasma antigen (Histo Ag) respectively. In Ghana, CM and DH are rarely suspected by clinicians due to limited epidemiological data.

Methods

This study was conducted among PWH in Ghana who are unwell. Sociodemographic and clinical data were collected by questionnaire. Serum and/or urine were screened for CrAg and Histo Ag, using IMMY CrAg lateral flow assay (LFA) and IMMY Histoplasma enzyme immunoassay (EIA) kits, respectively, regardless of symptoms. Samples run with IMMY Histoplasma EIA were simultaneously run with OIDx Histoplasma LFA. Laboratory investigations were conducted by the research team while diagnosis incorporating clinical assessment, screening and confirmatory testing results and treatment decisions were made by the clinical team. Treatment and outcome information on CM and DH patients were evaluated.

Results

Overall, 150 participants were recruited. There were 73% (n = 109) females, and the age range was 18–62 years. The prevalence rates of CrAg and Histo Ag were 2.7% (4/150) and 4.7% (5/107), respectively. The OIDx Histoplasma LFA showed a high concordance (98.4%) with the IMMY Histoplasma EIA. All antigen-positive cases by standard tests were diagnosed with CM and DH. Antifungal treatment was given in five patients and follow-up revealed two deaths and three recoveries.

Conclusion

Histoplasmosis among PWH may be more common than previously anticipated and may be more frequent than cryptococcosis in Ghana. The performance of the OIDx Histoplasma LFA should be further explored.

High Burden of Cryptococcal Meningitis Among ART-Experienced HIV-infected Patients in Northern Uganda in the era of “Test and Treat”: Implications for Cryptococcal Screening Programs

Background

The impact of the “test and treat” program for human immunodeficiency virus (HIV) treatment in rural areas of Uganda on cryptococcal antigen (CrAg) screening or cryptococcal meningitis (CM) is poorly understood.

Methods

We retrospectively evaluated clinical factors in 212 HIV-infected patients diagnosed with CM from February of 2017 to November of 2019 at Lira Regional Referral Hospital in northern Uganda.

Results

Among 212 patients diagnosed with CM, 58.5% were male. Median age was 35 years; CD4 count and HIV viral load (VL) were 86 cells/μL and 9463 copies/mL, respectively. Only 10% of patients had a previous history of CM. We found that 190 of 209 (90.9%) patients were ART experienced and 19 (9.1%) were ART naive. Overall, 90 of 212 (42.5%) patients died while hospitalized (median time to death, 14 days). Increased risk of death was associated with altered mental status (hazard ratio [HR], 6.6 [95% confidence interval {CI}, 2.411–18.219]; P ≤ .0001) and seizures (HR, 5.23 [95% CI, 1.245–21.991]; P = .024).

Conclusions

Current guidelines recommend CrAg screening based on low CD4 counts for ART-naive patients and VL or clinical failure for ART-experienced patients. Using current guidelines for CrAg screening, some ART-experienced patients miss CrAg screening in resource-limited settings, when CD4 or VL tests are unavailable. We found that the majority of HIV-infected patients with CM were ART experienced (90.9%) at presentation. The high burden of CM in ART-experienced patients supports a need for improved CrAg screening of ART-exposed patients.

Determining the burden of fungal infections in Zimbabwe

Zimbabwe currently faces several healthcare challenges, most notably HIV and associated infections including tuberculosis (TB), malaria and recently outbreaks of cholera, typhoid fever and COVID-19. Fungal infections, which are also a major public health threat, receive considerably less attention. Consequently, there is dearth of data regarding the burden of fungal diseases in the country. We estimated the burden of fungal diseases in Zimbabwe based on published literature and 'at-risk' populations (HIV/AIDS patients, survivors of pulmonary TB, cancer, chronic obstructive pulmonary disease, asthma and patients receiving critical care) using previously described methods. Where there was no data for Zimbabwe, regional, or international data was used. Our study revealed that approximately 14.9% of Zimbabweans suffer from fungal infections annually, with 80% having tinea capitis. The annual incidence of cryptococcal meningitis and Pneumocystis jirovecii pneumonia in HIV/AIDS were estimated at 41/100,000 and 63/100,000, respectively. The estimated prevalence of recurrent vulvovaginal candidiasis (RVVC) was 2,739/100,000. The estimated burden of fungal diseases in Zimbabwe is high in comparison to other African countries, highlighting the urgent need for increased awareness and surveillance to improve diagnosis and management.

Cryptococcal Antigen Screening Among Antiretroviral Therapy-Experienced People With HIV With Viral Load Nonsuppression in Rural Uganda

Background

The World Health Organization recommends screening for the cryptococcal antigen (CrAg), a predictor of cryptococcal meningitis, among antiretroviral therapy (ART)-naïve people with HIV (PWH) with CD4 <100 cells/mm³. CrAg positivity among ART-experienced PWH with viral load (VL) nonsuppression is not well established, yet high VLs are associated with cryptococcal meningitis independent of CD4 count. We compared the frequency and positivity yield of CrAg screening among ART-experienced PWH with VL nonsuppression and ART-naïve PWH with CD4 <100 cells/mm³ attending rural public health facilities in Uganda.

Methods

We reviewed routinely generated programmatic reports on cryptococcal disease screening from 104 health facilities in 8 rural districts of Uganda from January 2018 to July 2019. A lateral flow assay (IMMY CrAg) was used to screen for cryptococcal disease. PWH were eligible for CrAg screening if they were ART-naïve with CD4 <100 cell/mm³ or ART-experienced with an HIV VL >1000 copies/mL after at least 6 months of ART. We used Pearson's chi-square test to compare the frequency and yield of CrAg screening.

Results

Of 71860 ART-experienced PWH, 7210 (10.0%) were eligible for CrAg screening. Among 15417 ART-naïve PWH, 5719 (37.1%) had a CD4 count measurement, of whom 937 (16.4%) were eligible for CrAg screening. The frequency of CrAg screening was 11.5% (830/7210) among eligible ART-experienced PWH compared with 95.1% (891/937) of eligible ART- naïve PWH (P < .001). The CrAg positivity yield was 10.5% among eligible ART-experienced PWH compared with 13.8% among eligible ART-naïve PWH (P = .035).

Conclusions

The low frequency and high positivity yield of CrAg screening among ART-experienced PWH with VL nonsuppression suggest a need for VL- directed CrAg screening in this population. Studies are needed to evaluate the cost-effectiveness and impact of CrAg screening and fluconazole prophylaxis on the outcomes of ART-experienced PWH with VL nonsuppression.