Development and validation of quantitative PCR assays for HIV-associated cryptococcal meningitis in sub-Saharan Africa: a diagnostic accuracy study

BACKGROUND

HIV-associated cryptococcal meningitis is the second leading cause of AIDS-related deaths, with a 10-week mortality rate of 25-30%. Fungal load assessed by colony-forming unit (CFU) counts is used as a prognostic marker and to monitor response to treatment in research studies. PCR-based assessment of fungal load could be quicker and less labour-intensive. We sought to design, optimise, and validate quantitative PCR (qPCR) assays for the detection, identification, and quantification of Cryptococcus infections in patients with cryptococcal meningitis in sub-Saharan Africa.

METHODS

We developed and validated species-specific qPCR assays based on DNA amplification of QSP1 (QSP1A specific to Cryptococcus neoformans, QSP1B/C specific to Cryptococcus deneoformans, and QSP1D specific to Cryptococcus gattii species) and a pan-Cryptococcus assay based on a multicopy 28S rRNA gene. This was a longitudinal study that validated the designed assays on cerebrospinal fluid (CSF) of 209 patients with cryptococcal meningitis at baseline (day 0) and during anti-fungal therapy (day 7 and day 14), from the AMBITION-cm trial in Botswana and Malawi (2018-21). Eligible patients were aged 18 years or older and presenting with a first case of cryptococcal meningitis.

FINDINGS

When compared with quantitative cryptococcal culture as the reference, the sensitivity of the 28S rRNA was 98·2% (95% CI 95·1-99·5) and of the QSP1 assay was 90·4% (85·2-94·0) in CSF at day 0. Quantification of the fungal load with QSP1 and 28S rRNA qPCR correlated with quantitative cryptococcal culture (R2=0·73 and R2=0·78, respectively). Both Botswana and Malawi had a predominant C neoformans prevalence of 67% (95% CI 55-75) and 68% (57-73), respectively, and lower C gattii rates of 21% (14-31) and 8% (4-14), respectively. We identified ten patients that, after 14 days of treatment, harboured viable but non-culturable yeasts based on QSP1 RNA detection (without any positive CFU in CSF culture).

INTERPRETATION

QSP1 and 28S rRNA assays are useful in identifying Cryptococcus species. qPCR results correlate well with baseline quantitative cryptococcal culture and show a similar decline in fungal load during induction therapy. These assays could be a faster alternative to quantitative cryptococcal culture to determine fungal load clearance. The clinical implications of the possible detection of viable but non-culturable cells in CSF during induction therapy remain unclear.

FUNDING

European and Developing Countries Clinical Trials Partnership; Swedish International Development Cooperation Agency; Wellcome Trust/UK Medical Research Council/UKAID Joint Global Health Trials; and UK National Institute for Health Research.

Tracking cryptococcal meningitis to monitor HIV program success during the Treat-All era: an analysis of national data in Botswana

BACKGROUND

Cryptococcal meningitis causes substantial mortality in high-HIV prevalence African countries despite advances in disease management and increasing antiretroviral therapy coverage. Reliable diagnosis of cryptococcal meningitis is cheap and more accessible than other indicators of AHD burden such as CD4 testing or investigation for disseminated tuberculosis; therefore, monitoring cryptococcal meningitis incidence has the potential to serve as a valuable metric of HIV programmatic success.

METHODS

Botswana national meningitis surveillance data from 2015 to 2022 were obtained from electronic health records. All electronic laboratory records from cerebrospinal fluid samples analysed within government healthcare facilities in Botswana were extracted from a central online repository. Adjustments for missing data were made through triangulation with prospective cohort study datasets. Cryptococcal meningitis case frequency was enumerated using a case definition and incidence calculated using national census data.

RESULTS

A total of 1,744 episodes of cryptococcal meningitis were identified; incidence declined from 15.0 (95% CI 13.4-16.7) cases/100,000 person-years in 2015 to 7.4 (95% CI 6.4-8.6) cases/100,000 person-years in 2022. However, the rate of decline slowed following the introduction of universal treatment in 2016. The highest incidence was observed in men and individuals aged 40-44. The proportion of cases diagnosed through cryptococcal antigen testing increased from 35.5% to 86.3%.

CONCLUSION

Cryptococcal meningitis incidence has decreased in Botswana following expansion of ART coverage but persists at a stubbornly high incidence. Most cases are now diagnosed through the cheap and easy-to-use cryptococcal antigen test highlighting the potential of using cryptococcal meningitis as key metric of programme success in the Treat All era.

Pathways to care with HIV-associated cryptococcal meningitis in Botswana and Uganda: Findings from a qualitative methods study

HIV-associated cryptococcal meningitis remains a key driver of AIDS-related mortality. Mortality is twice as high in those who present later to care and with severe symptoms such as confusion. We embedded a qualitative methods study within a randomised controlled trial in Gaborone, Botswana and Kampala, Uganda with the aim of understanding pathways to care. We conducted in-depth interviews with trial participants and surrogate decision makers and analysed data thematically. Between January 2020 and June 2021 we interviewed 58 individuals. Pathways to care were prolonged because headaches were disregarded by participants and healthcare workers as a common occurrence with a broad differential diagnosis of predominantly benign aetiologies. There was also a lack of awareness of cryptococcal meningitis, and it was often after HIV was diagnosed or disclosed that the pathway accelerated, resulting in hospital admission. We outline key recommendations to reduce mortality and argue for the integration of social and behavioural interventions within differentiated service delivery models for advanced HIV disease.

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.

Reduction in mortality from HIV-related CNS infections in routine care in Africa (DREAMM): a before-and-after, implementation study

BACKGROUND

Four decades into the HIV epidemic, CNS infection remains a leading cause of preventable HIV-related deaths in routine care. The Driving Reduced AIDS-associated Meningo-encephalitis Mortality (DREAMM) project aimed to develop, implement, and evaluate pragmatic implementation interventions and strategies to reduce mortality from HIV-related CNS infection.

METHODS

DREAMM took place in five public hospitals in Cameroon, Malawi, and Tanzania. The main intervention was a stepwise algorithm for HIV-related CNS infections including bedside rapid diagnostic testing and implementation of WHO cryptococcal meningitis guidelines. A health system strengthening approach for hospitals was adopted to deliver quality care through a co-designed education programme, optimised clinical and laboratory pathways, and communities of practice. DREAMM was led and driven by local leadership and divided into three phases: observation (including situational analyses of routine care), training, and implementation. Consecutive adults (aged ≥18 years) living with HIV presenting with a first episode of suspected CNS infection were eligible for recruitment. The primary endpoint was the comparison of 2-week all-cause mortality between observation and implementation phases. This study completed follow-up in September, 2021. The project was registered on ClinicalTrials.gov, NCT03226379.

FINDINGS

From November, 2016 to April, 2019, 139 eligible participants were enrolled in the observation phase. From Jan 9, 2018, to March 25, 2021, 362 participants were enrolled into the implementation phase. 216 (76%) of 286 participants had advanced HIV disease (209 participants had missing CD4 cell count), and 340 (69%) of 494 participants had exposure to antiretroviral therapy (ART; one participant had missing ART data). In the implementation phase 269 (76%) of 356 participants had a probable CNS infection, 203 (76%) of whom received a confirmed microbiological or radiological diagnosis of CNS infection using existing diagnostic tests and medicines. 63 (49%) of 129 participants died at 2 weeks in the observation phase compared with 63 (24%) of 266 in the implementation phase; and all-cause mortality was lower in the implementation phase when adjusted for site, sex, age, ART exposure (adjusted risk difference -23%, 95% CI -33 to -13; p<0·001). At 10 weeks, 71 (55%) died in the observation phase compared with 103 (39%) in the implementation phase (-13%, -24 to -3; p=0·01).

INTERPRETATION

DREAMM substantially reduced mortality from HIV-associated CNS infection in resource-limited settings in Africa. DREAMM scale-up is urgently required to reduce deaths in public hospitals and help meet Sustainable Development Goals.

FUNDING

European and Developing Countries Clinical Trials Partnership, French Agency for Research on AIDS and Viral Hepatitis.

TRANSLATIONS

For the French and Portuguese translations of the abstract see Supplementary Materials section.

Population pharmacokinetics and CSF penetration of flucytosine in adults with HIV-associated cryptococcal meningoencephalitis

BACKGROUND

There are limited data describing clinical flucytosine pharmacokinetics (PK). The variability of flucytosine partitioning into the CNS is not known. We described the interindividual variability in flucytosine PK in patients with HIV-associated cryptococcal meningoencephalitis. In addition, we quantified the extent and variability of CSF partitioning of flucytosine.

METHODS

A PK study was conducted in 64 patients with confirmed HIV-associated cryptococcal meningoencephalitis in Blantyre, Malawi. A four-compartment PK model was developed, and Monte Carlo simulations were performed with flucytosine administered at different doses and in different schedules.

RESULTS

The estimated mean apparent volume of the central compartment was 17.50 (SD 9.99) L; mean apparent clearance was 5.88 (SD 3.35) L/h; mean apparent volume of the CNS compartment was 41.73 (SD 13.66) L. From the Bayesian posterior estimates, AUC24 values at steady state (144-168 h) with doses of 25 mg/kg q6h were median (IQR) 890.38 (603.81-1213.70) mg.h/L in plasma and 595.66 (425.69-776.64) mg.h/L in CSF. The ratio of CSF:plasma AUC24 was 0.69 (IQR 0.58-0.82).

CONCLUSIONS

This study revealed significant interindividual variability in flucytosine PK in plasma and CSF in patients with HIV-associated cryptococcal meningoencephalitis. The population PK model is a first critical step for revised flucytosine regimens that maximize fungal killing and minimize toxicity and the emergence of resistance.

How Applicable Is the Single-Dose AMBITION Regimen for Human Immunodeficiency Virus-Associated Cryptococcal Meningitis to High-Income Settings?

The AmBisome Therapy Induction Optimization (AMBITION-cm) trial, conducted in eastern and southern Africa, showed that a single, high dose (10 mg/kg) of liposomal amphotericin B, given with an oral backbone of fluconazole and flucytosine, was noninferior to the World Health Organization (WHO)-recommended regimen of 7 days of amphotericin B deoxycholate plus flucytosine for treatment of human immunodeficiency virus (HIV)-associated cryptococcal meningitis and has been incorporated into WHO treatment guidelines. We believe that the trial also has important implications for the treatment of HIV-associated cryptococcal meningitis in high-income settings. We advance the arguments, supported by evidence where available, that the AMBITION-cm trial regimen is likely to be as fungicidal as the currently recommended 14-day liposomal amphotericin-based treatments, better tolerated with fewer adverse effects, and confer significant economic and practical benefits and, therefore, should be included as a treatment option in guidance for HIV-associated cryptococcal treatment in high-income settings.

Correction: Equity in clinical trials for HIV-associated cryptococcal meningitis: A systematic review of global representation and inclusion of patients and researchers

[This corrects the article DOI: 10.1371/journal.pntd.0009376.].

Clinical research for life-threatening illnesses requiring emergency hospitalisation: a critical interpretive synthesis of qualitative data related to the experience of participants and their caregivers

BACKGROUND

Research into life-threatening illnesses which require emergency hospitalisation is essential. This group of patients is unique in that they are experiencing an unfolding emergency when they are approached, enrolled, and followed up in a research study. We aimed to synthesise qualitative data from trial participants and surrogate decision-makers to deepen our understanding and inform the design and conduct of future clinical trials for life-threatening illnesses.

METHODS

We conducted a critical interpretive synthesis of qualitative data from trial participants and surrogate decision-makers related to the experience of participating in a clinical research study when suffering from a life-threatening illness. A scoping review informed a systematic review of published data. We searched research databases and reviewed papers for inclusion. Primary data and interpretations of data were extracted from each paper. Data were analysed using reciprocal translational analysis, refutational synthesis, and lines of argument synthesis to develop a synthetic construct.

RESULTS

Twenty-two papers were included. Most individuals had no previous knowledge or experience with clinical research. Individuals making decisions were directly experiencing or witness to an unfolding emergency which came with a myriad of physical and psychological symptoms. It was difficult to differentiate clinical research and routine care, and understanding of core concepts around research, particularly randomisation and equipoise, was limited. We found that this led to an underestimation of risk, an overestimation of benefit, and an expectation of being allocated to the intervention arm. The decision-making process was heavily influenced by trust in the research team. Individuals suggested that abbreviated information, presented in different ways and continuously throughout the research process, would have increased knowledge and satisfaction with the research process.

CONCLUSION

Individuals suffering from a life-threatening illness who are being invited to participate in clinical research need to be managed in a way that adapts to the severity of their illness and there is a need to tailor research processes, including informed consent, accordingly. We provide suggestions for further research and implementation work around research participation for individuals suffering from a life-threatening illness.

TRIAL REGISTRATION

PROSPERO CRD42020207296.

High concordance in plasma and CSF HIV-1 drug resistance mutations despite high cases of CSF viral escape in individuals with HIV-associated cryptococcal meningitis in Botswana

OBJECTIVES

We compared the patterns of HIV-1 drug resistance mutations between the CSF and plasma of individuals with HIV-associated cryptococcal meningitis.

METHODS

This is a cross-sectional study of archived CSF and plasma samples collected from ART-exposed participants recruited in the Phase 3 AmBisome Therapy Induction Optimisation randomized controlled trial (ISRCTN72509687) conducted in Botswana between 2018 and 2021. HIV-1 RT and protease genes were genotyped using next-generation sequencing and HIV-1 drug resistance mutations were compared between the CSF and plasma compartments stratified by thresholds of ≥20% and <20%.

RESULTS

Overall, 66.7% (16/24) of participants had at least one HIV-1 drug resistance mutation in the CSF and/or plasma. A total of 15/22 (68.2%) participants had HIV-1 drug resistance mutations at ≥20% threshold in the plasma and of those, 11 (73.3%) had been on ART longer than 6 months. HIV-1 drug resistance mutations were highly concordant between the CSF and plasma at ≥20% threshold despite a substantial number of individuals experiencing CSF viral escape and with only 54.5% with CSF WBC count ≥20 cells/mm3. Minority HIV-1 drug resistance mutations were detected in 20.8% (5/24) of participants. There were no mutations in the CSF that were not detected in the plasma.

CONCLUSIONS

There was high concordance in HIV-1 drug resistance mutations in the CSF and plasma, suggesting intercompartmental mixing and possibly a lack of compartmentalization. Some individuals harboured minority HIV-1 drug resistance mutations, demonstrating the need to employ more sensitive genotyping methods such as next-generation sequencing for the detection of low-abundance mutations.

Population pharmacokinetics of liposomal amphotericin B in adults with HIV-associated cryptococcal meningoencephalitis

BACKGROUND

Single, high-dose liposomal amphotericin B (LAmB; AmBisome, Gilead Sciences) has demonstrated non-inferiority to amphotericin B deoxycholate in combination with other antifungals for averting all-cause mortality from HIV-associated cryptococcal meningitis. There are limited data on the pharmacokinetics (PK) of AmBisome. The aim of this study was to describe population PK of AmBisome and conduct a meta-analysis of the available studies to suggest the optimal dosing for cryptococcal meningoencephalitis.

METHODS

Data from a Phase II and Phase III trial of high-dose, short-course AmBisome for cryptococcal meningoencephalitis were combined to develop a population PK model. A search was conducted for trials of AmBisome monotherapy and meta-analysis of clinical outcome data was performed.

RESULTS

A two-compartment model with first-order clearance of drug from the central compartment fitted the data best and enabled the extent of inter-individual variability in PK to be quantified. Mean (SD) population PK parameter estimates were: clearance 0.416 (0.363)  L/h; volume of distribution 4.566 (4.518) L; first-order transfer of drug from central to peripheral compartments 2.222 (3.351)  h-1, and from peripheral to central compartment 2.951 (4.070)  h-1. Data for the meta-analysis were insufficient to suggest optimal dosing of AmBisome for cryptococcal meningoencephalitis.

CONCLUSIONS

This study provides novel insight into the PK of AmBisome at the population level and the variability therein. Our analysis also serves to highlight the paucity of data available on the pharmacodynamics (PD) of AmBisome and underscores the importance of thorough and detailed PK/PD analysis in the development of novel antifungals, by demonstrating the challenges associated with post hoc PK/PD analysis.

Laboratory Evaluation of the VISITECT Advanced Disease Semiquantitative Point-of-Care CD4 Test

BACKGROUND

Advanced HIV disease (AHD; CD4 counts <200 cells/µL) remains common in many low- and middle-income settings. An instrument-free point-of-care test to rapidly identify patients with AHD would facilitate implementation of the World Health Organization (WHO) recommended package of care. We performed a laboratory-based validation study to evaluate the performance of the VISITECT CD4 Advanced Disease assay in Botswana.

SETTING

A laboratory validation study.

METHODS

Venous blood samples from people living with HIV having baseline CD4 testing in Gaborone, Botswana, underwent routine testing using flow cytometry, followed by testing with the VISITECT CD4 Advanced Disease assay by a laboratory scientist blinded to the flow cytometry result with a visual read to determine whether the CD4 count was below 200 cells/µL. A second independent investigator conducted a visual read blinded to the results of flow cytometry and the initial visual read. The sensitivity and specificity of the VISITECT for detection of AHD were determined using flow cytometry as a reference standard, and interrater agreement in VISITECT visual reads assessed.

RESULTS

One thousand fifty-three samples were included in the analysis. The VISITECT test correctly identified 112/119 samples as having a CD4 count <200 cells/µL, giving a sensitivity of 94.1% (95% confidence interval: 88.3% to 97.6%) and specificity of 85.9% (95% confidence interval: 83.5% to 88.0%) compared with flow cytometry. Interrater agreement between the 2 independent readers was 97.5%, Kappa 0.92 ( P < 0.001).

CONCLUSIONS

The VISITECT CD4 advanced disease reliably identified individuals with low CD4 counts and could facilitate implementation of the WHO recommended package of interventions for AHD.

Cost-effectiveness of single, high-dose, liposomal amphotericin regimen for HIV-associated cryptococcal meningitis in five countries in sub-Saharan Africa: an economic analysis of the AMBITION-cm trial

BACKGROUND

HIV-associated cryptococcal meningitis is a leading cause of AIDS-related mortality. The AMBITION-cm trial showed that a regimen based on a single high dose of liposomal amphotericin B deoxycholate (AmBisome group) was non-inferior to the WHO-recommended treatment of seven daily doses of amphotericin B deoxycholate (control group) and was associated with fewer adverse events. We present a five-country cost-effectiveness analysis.

METHODS

The AMBITION-cm trial enrolled patients with HIV-associated cryptococcal meningitis from eight hospitals in Botswana, Malawi, South Africa, Uganda, and Zimbabwe. Taking a health service perspective, we collected country-specific unit costs and individual resource-use data per participant over the 10-week trial period, calculating mean cost per participant by group, mean cost-difference between groups, and incremental cost-effectiveness ratio per life-year saved. Non-parametric bootstrapping and scenarios analyses were performed including hypothetical real-world resource use. The trial registration number is ISRCTN72509687, and the trial has been completed.

FINDINGS

The AMBITION-cm trial enrolled 844 participants, and 814 were included in the intention-to-treat analysis (327 from Uganda, 225 from Malawi, 107 from South Africa, 84 from Botswana, and 71 from Zimbabwe) with 407 in each group, between Jan 31, 2018, and Feb 17, 2021. Using Malawi as a representative example, mean total costs per participant were US$1369 (95% CI 1314-1424) in the AmBisome group and $1237 (1181-1293) in the control group. The incremental cost-effectiveness ratio was $128 (59-257) per life-year saved. Excluding study protocol-driven cost, using a real-world toxicity monitoring schedule, the cost per life-year saved reduced to $80 (15-275). Changes in the duration of the hospital stay and antifungal medication cost showed the greatest effect in sensitivity analyses. Results were similar across countries, with the cost per life-year saved in the real-world scenario ranging from $71 in Botswana to $121 in Uganda.

INTERPRETATION

The AmBisome regimen was cost-effective at a low incremental cost-effectiveness ratio. The regimen might be even less costly and potentially cost-saving in real-world implementation given the lower drug-related toxicity and the potential for shorter hospital stays.

FUNDING

European Developing Countries Clinical Trials Partnership, Swedish International Development Cooperation Agency, Wellcome Trust and Medical Research Council, UKAID Joint Global Health Trials, and the National Institute for Health Research.

TRANSLATIONS

For the Chichewa, Isixhosa, Luganda, Setswana and Shona translations of the abstract see Supplementary Materials section.

The acceptability of the AMBITION-cm treatment regimen for HIV-associated cryptococcal meningitis: Findings from a qualitative methods study of participants and researchers in Botswana and Uganda

BACKGROUND

The AMBITION-cm trial for HIV-associated cryptococcal meningitis demonstrated that a single, high-dose of liposomal amphotericin (AmBisome) plus 14-days of oral flucytosine and fluconazole was non-inferior in terms of all-cause mortality to 7-days of amphotericin B deoxycholate and flucytosine followed by 7-days of fluconazole (Control). The AmBisome regimen was associated with fewer adverse events. We explored the acceptability of the AmBisome regimen from the perspective of participants and providers.

METHODS

We embedded a qualitative methods study within the AMBITION-cm sites in Botswana and Uganda. We conducted in-depth interviews with trial participants, surrogate decision makers, and researchers and combined these with direct observations. Interviews were transcribed, translated, and analysed thematically.

RESULTS

We interviewed 38 trial participants, 20 surrogate decision makers, and 31 researchers. Participant understanding of the trial was limited; however, there was a preference for the AmBisome regimen due to the single intravenous dose and fewer side effects. More time was required to prepare the single AmBisome dose but this was felt to be acceptable given subsequent reductions in workload. The AmBisome regimen was reported to be associated with fewer episodes of rigors and thrombophlebitis and a reduction in the number of intravenous cannulae required. Less intensive monitoring and management was required for participants in the AmBisome arm.

CONCLUSIONS

The AmBisome regimen was highly acceptable, being simpler to administer despite the initial time investment required. The regimen was well tolerated and associated with less toxicity and resultant management. Widespread implementation would reduce the clinical workload of healthcare workers caring for patients with HIV-associated cryptococcal meningitis.

S1.4d Cryptococcus qPCR assays: the future for routine mycology labs and clinical trials dealing with cryptococcosis

S1.4 Fungal infections in Asia, bringing it out of the dark, September 21, 2022, 11:00 AM - 12:30 PM

 

Background

Routine laboratory testing for cryptococcal meningitis currently consists of Cryptococcal antigen (CrAg) testing in blood and cerebrospinal fluid (CSF), CSF India ink, and CSF fungal culture. Quantitative cryptococcal culture (QCC) is labor intensive and not feasible in most settings.

Objectives

We evaluated quantitative (qPCR) and reverse transcriptase qPCR (RT-qPCR) assays to quantify cryptococcal load in CSF, plasma, and blood. We also investigated the dynamics of fungal DNA and RNA detection during antifungal treatment.

Methods

We developed a qPCR assay that can differentiate serotypes A, D, and B/C of Cryptococcus neoformans and C. gattii based on the amplification of a unique nuclear Quorum sensing protein 1 (QSP1) and a multicopy 28S rRNA gene and evaluated the assays on 205-patient samples from the AMBITION-cm trial in Botswana and Malawi (2018-2021). CSF, plasma, and whole blood samples were stored per patient and were sampled at day 0 (baseline), day 7 and 14 for CSF and at day 1, 3 and 7 for plasma and whole blood post antifungal treatment initiation. A Roche LightCycler480 and Graph pad prism were used for data analysis.

Results

A total of 205/209 stored patient samples (85 from Botswana; 124 from Malawi), were used. For QSP1 qPCR tested in CSF at D0, 138 (81.7%) were serotype A, 28 (16.6%) were serotype B/C and 3 (1.8%) were a mixed infection of serotype A and B/C. There was no amplification with 36 (17.6%) samples. There was no difference in fungal loads at D0, D7, and D14 between serotype A and B/C with the QSP1 qPCR assay, and QCC. QCC showed a good correlation with qPCR quantification with QSP1 qPCR (slope = 0.797, R2 = 0.73) and with 28S rRNA qPCR (Slope = 0.771, R2 = 0.778) assays. The fungal load at D0 was significantly higher in patients who died at week 2 (w2) and at week 10 (w10) as compared with patients who survived post-week 10 (P <.01), with no significant difference in initial fungal load in both treatment regimens (P >.05). Detection of Cryptococcus DNA (28S rRNA qPCR) in plasma or whole blood within the first 24 h of treatment was significantly associated with early mortality at w2 and mortality at w10 (P <.01). QSP1 RT-qPCR showed that detection of DNA was due to viable fungal cells as the quantification of QSP1 whole nucleic acids was systematically higher (X2 to 5) than that of DNA.

Conclusion

Quantification of C. neoformans and C. gattii load in CSF and plasma at D0 is useful in identifying patients at risk of death and may be a promising tool for monitoring treatment response in the future.

Association of Hyponatremia on Mortality in Cryptococcal Meningitis: A Prospective Cohort

Background

Sodium abnormalities are frequent in central nervous system infections and may be caused by cerebral salt wasting, syndrome of inappropriate antidiuretic hormone secretion, or medication adverse events. In cryptococcal meningitis (CM), the prevalence of baseline hyponatremia and whether hyponatremia adversely impacts survival is unknown.

Methods

We conducted a secondary analysis of data from 2 randomized trials of human immunodeficiency virus-infected adult Ugandans with CM. We grouped serum sodium into 3 categories: <125, 125-129, and 130-145 mmol/L. We assessed whether baseline sodium abnormalities were associated with clinical characteristics and survival.

Results

Of 816 participants with CM, 741 (91%) had a baseline sodium measurement available: 121 (16%) had grade 3-4 hyponatremia (<125 mmol/L), 194 (26%) had grade 2 hyponatremia (125-129 mmol/L), and 426 (57%) had a baseline sodium of 130-145 mmol/L. Hyponatremia (<125 mmol/L) was associated with higher initial cerebrospinal fluid (CSF) quantitative culture burden (P < .001), higher initial CSF opening pressure (P < .01), lower baseline Glasgow Coma Scale score (P < .01), and a higher percentage of baseline seizures (P = .03). Serum sodium <125 mmol/L was associated with increased 2-week mortality in unadjusted and adjusted survival analyses (adjusted hazard ratio, 1.87 [95% confidence interval, 1.26-2.79]; P < .01) compared to those with sodium 130-145 mmol/L.

Conclusions

Hyponatremia is common in CM and is associated with excess mortality. A standardized management approach to correctly diagnose and correct hyponatremia in CM needs to be developed and tested.

Decision making in a clinical trial for a life-threatening illness: Therapeutic expectation, not misconception

Potential participants for clinical trials which aim to define treatments for life-threatening conditions are often extremely unwell. When exploring why individuals participate in clinical trials one common observation is a misplaced expectation of personal benefit - a therapeutic misconception. The care offered in some clinical trials is of a higher standard than is routinely available and this has led to criticism around the freedom of choice to enrol - structural coercion. We embedded an ethnographic study within a randomised controlled trial for HIV-associated cryptococcal meningitis in Gaborone, Botswana and Kampala, Uganda. We aimed to gain an understanding of decision-making around the trial and how this was impacted by the study design and broader social context. We conducted in-depth interviews with trial participants, surrogate decision makers and researchers, combined these with direct observations and analysed data using thematic analysis. Between January 2020 and June 2021 we interviewed 89 individuals. We found previous exposure to and awareness of clinical research was limited, as was understanding of the trial objectives and design. Through observations and engagement with healthcare facilities decision-makers were able to identify the trial as providing the best possible chance of survival. Hesitation and reluctance were mostly due to fear of lumbar punctures which was sometimes based on rumours but often based on tragic personal experience. Despite fear, and sometimes conviction that they would die, individuals agreed to consent, often against the wishes of family members. Reassurance and confidence came from trust in routine care staff and the research team but also from fellow participants and their surrogates. We argue that participants made informed decisions based on a therapeutic expectation from the trial and that rather than being the result of structural coercion this was an informed and voluntary choice.

Reversal of CSF HIV-1 Escape during Treatment of HIV-Associated Cryptococcal Meningitis in Botswana

Cerebrospinal fluid (CSF) viral escape has been poorly described among people with HIV-associated cryptococcal meningitis. We determined the prevalence of CSF viral escape and HIV-1 viral load (VL) trajectories in individuals treated for HIV-associated cryptococcal meningitis. A retrospective longitudinal study was performed using paired CSF and plasma collected prior to and during the antifungal treatment of 83 participants recruited at the Botswana site of the phase-3 AMBITION-cm trial (2018−2021). HIV-1 RNA levels were quantified then CSF viral escape (CSF HIV-1 RNA ≥ 0.5 log10 higher than plasma) and HIV-1 VL trajectories were assessed. CSF viral escape occurred in 20/62 (32.3%; 95% confidence interval [CI]: 21.9−44.6%), 13/52 (25.0%; 95% CI: 15.2−38.2%) and 1/33 (3.0%; 95% CI: 0.16−15.3%) participants at days 1, 7 and 14 respectively. CSF viral escape was significantly lower on day 14 compared to days 1 and 7, p = 0.003 and p = 0.02, respectively. HIV-1 VL decreased significantly from day 1 to day 14 post antifungal therapy in the CSF but not in the plasma (β = −0.47; 95% CI: −0.69 to −0.25; p < 0.001). CSF viral escape is high among individuals presenting with HIV-associated cryptococcal meningitis; however, antifungal therapy may reverse this, highlighting the importance of rapid initiation of antifungal therapy in these patients.

Assessment of Photoreleasable Linkers and Light-Capturing Antennas on a Photoresponsive Cobalamin Scaffold

Cobalamin has shown promise as a light-sensitive drug delivery platform owing to its ease of modification and the high quantum yields for drug photorelease. However, studies to date on the general photochemistry of alkyl cobalamins have primarily focused on methyl and adenosyl-substituted derivatives, the natural cofactors present in various enzymatic species. We describe the synthesis and photolytic behavior of cobalamin conjugates comprised of different combinations of fluorophores and β-axial ligands. In general, cobalamin conjugates containing β-axial alkyl substituents undergo efficient photolysis under aqueous conditions, with quantum yields up to >40%. However, substituents that are large and hydrophobic, or unable to readily support the presumed radical intermediate, suffer less efficient photolysis (<15%) than smaller, water-soluble, analogs. By contrast, quantum yields improve by 2-fold in DMF for cobalamins containing large hydrophobic β-axial substituents. This suggests that drug release from carriers comprised of membranous compartments, such as liposomes, may be significantly more efficient than the corresponding photorelease in an aqueous environment. Finally, we explored the impact of fluorophores on the photolysis of alkyl cobalamins under tissue-mimetic conditions. Cobalamins substituted with efficient photon-capturing fluorophores display up to 4-fold enhancements in photolysis relative to unsubstituted derivatives. In summary, we have shown that the photosensitivity of alkyl cobalamin conjugates can be tuned by altering the Co-appended alkyl moiety, modulating the polarity of the environment (solvent), and installing photon-capturing fluorophores onto the cobalamin framework.

Single-Dose Liposomal Amphotericin B Treatment for Cryptococcal Meningitis

BACKGROUND

Cryptococcal meningitis is a leading cause of human immunodeficiency virus (HIV)-related death in sub-Saharan Africa. Whether a treatment regimen that includes a single high dose of liposomal amphotericin B would be efficacious is not known.

METHODS

In this phase 3 randomized, controlled, noninferiority trial conducted in five African countries, we assigned HIV-positive adults with cryptococcal meningitis in a 1:1 ratio to receive either a single high dose of liposomal amphotericin B (10 mg per kilogram of body weight) on day 1 plus 14 days of flucytosine (100 mg per kilogram per day) and fluconazole (1200 mg per day) or the current World Health Organization-recommended treatment, which includes amphotericin B deoxycholate (1 mg per kilogram per day) plus flucytosine (100 mg per kilogram per day) for 7 days, followed by fluconazole (1200 mg per day) for 7 days (control). The primary end point was death from any cause at 10 weeks; the trial was powered to show noninferiority at a 10-percentage-point margin.

RESULTS

A total of 844 participants underwent randomization; 814 were included in the intention-to-treat population. At 10 weeks, deaths were reported in 101 participants (24.8%; 95% confidence interval [CI], 20.7 to 29.3) in the liposomal amphotericin B group and 117 (28.7%; 95% CI, 24.4 to 33.4) in the control group (difference, -3.9 percentage points); the upper boundary of the one-sided 95% confidence interval was 1.2 percentage points (within the noninferiority margin; P<0.001 for noninferiority). Fungal clearance from cerebrospinal fluid was -0.40 log10 colony-forming units (CFU) per milliliter per day in the liposomal amphotericin B group and -0.42 log10 CFU per milliliter per day in the control group. Fewer participants had grade 3 or 4 adverse events in the liposomal amphotericin B group than in the control group (50.0% vs. 62.3%).

CONCLUSIONS

Single-dose liposomal amphotericin B combined with flucytosine and fluconazole was noninferior to the WHO-recommended treatment for HIV-associated cryptococcal meningitis and was associated with fewer adverse events. (Funded by the European and Developing Countries Clinical Trials Partnership and others; Ambition ISRCTN number, ISRCTN72509687.).

Light-Triggered Drug Release from Red Blood Cells Suppresses Arthritic Inflammation

Arthritis is a leading cause of disability in adults, which can be intensely incapacitating. The location and intensity of the pain is both subjective and challenging to manage. Consequently, patient-directed delivery of anti-inflammatories is an essential component of future therapeutic strategies for the management of this disorder. We describe the design and application of a light responsive red blood cell (RBC) conveyed dexamethasone (Dex) construct that enables targeted drug delivery upon illumination of the inflamed site. The red wavelength (650 nm) responsive nature of the phototherapeutic was validated using tissue phantoms mimicking the light absorbing properties of various skin types. Furthermore, photoreleased Dex has the same impact on cellular responses as conventional Dex. Murine RBCs containing the photoactivatable therapeutic display comparable circulation properties as fluorescently labelled RBCs. In addition, a single dose of light-targeted Dex delivery is 5-fold more effective in suppressing inflammation than the parent drug, delivered serially over multiple days. These results are consistent with the notion that the circulatory system be used as an on-command drug depot, providing the means to therapeutically target diseased sites both efficiently and effectively.

Photoactivatable Reporter to Perform Multiplexed and Temporally Controlled Measurements of Kinase and Protease Activity in Single Cells

Peptide bioreporters were developed to perform multiplexed measurements of the activation of epidermal growth factor receptor kinase (EGFR), Akt kinase (Akt/protein kinase B), and proteases/peptidases in single cells. The performance characteristics of the three reporters were assessed by measuring the reporter's proteolytic stability, kinetic constants for EGFR and Akt, and dephosphorylation rate. The reporter displaying optimal performance was composed of 6-carboxyfluorescein (6-FAM) on the peptide N-terminus, an Akt substrate sequence employing a threonine phosphorylation site for Akt, followed by a tri-D arginine linker, and finally an EGFR substrate sequence bearing a phosphatase-resistant 7-(S)-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (L-htc) residue as the EGFR phosphorylation site. Importantly, use of a single electrophoretic condition separated the mono- and diphosphorylated products as well as proteolytic forms permitting the quantitation of multiple enzyme activities simultaneously using a single reporter. Because the Akt and EGFR substrates were linked, a known ratio (EGFR/Akt) of the reporter was loaded into cells. A photoactivatable version of the reporter was synthesized by adding two 4,5-dimethoxy-2-nitrobenzyl (DMNB) moieties to mask the EGFR and Akt phosphorylation sites. The DMNB moieties were readily photocleaved following exposure to 360 nm light, unmasking the phosphorylation sites on the reporter. The new photoactivatable reporter permitted multiplexed measurements of kinase signaling and proteolytic degradation in single cells in a temporally controlled manner. This work will facilitate the development of a new generation of multiplexed activity-based reporters capable of light-initiated measurement of enzymatic activity in single cells.

Equity in clinical trials for HIV-associated cryptococcal meningitis: A systematic review of global representation and inclusion of patients and researchers

Background

It is essential that clinical trial participants are representative of the population under investigation. Using HIV-associated cryptococcal meningitis (CM) as a case study, we conducted a systematic review of clinical trials to determine how inclusive and representative they were both in terms of the affected population and the involvement of local investigators.

Methods

We searched Medline, EMBASE, Cochrane, Africa-Wide, CINAHL Plus, and Web of Science. Data were extracted for 5 domains: study location and design, screening, participants, researchers, and funders. Data were summarised and compared over 3 time periods: pre-antiretroviral therapy (ART) (pre-2000), early ART (2000 to 2009), and established ART (post-2010) using chi-squared and chi-squared for trend. Comparisons were made with global disease burden estimates and a composite reference derived from observational studies.

Results

Thirty-nine trials published between 1990 and 2019 were included. Earlier studies were predominantly conducted in high-income countries (HICs) and recent studies in low- and middle-income countries (LMICs). Most recent studies occurred in high CM incidence countries, but some highly affected countries have not hosted trials. The sex and ART status of participants matched those of the general CM population. Patients with reduced consciousness and those suffering a CM relapse were underrepresented. Authorship had poor representation of women (29% of all authors), particularly as first and final authors. Compared to trials conducted in HICs, trials conducted in LMICs were more likely to include female authors (32% versus 20% p = 0.014) but less likely to have authors resident in (75% versus 100%, p < 0.001) or nationals (61% versus 93%, p < 0.001) of the trial location.

Conclusions

There has been a marked shift in CM trials over the course of the HIV epidemic. Trials are primarily performed in locations and populations that reflect the burden of disease, but severe and relapse cases are underrepresented. Most CM trials now take place in LMICs, but the research is primarily funded and led by individuals and institutions from HICs.

It is essential that clinical trial participants are representative of the population under investigation. Similarly, research must meaningfully include researchers who are from and/or based in the location where the study is being conducted, both to ensure that the research matches the local need but also to promote equity in research. Using clinical trials in HIV-associated cryptococcal meningitis as a case study, we conducted a systematic review to determine how inclusive and representative trials have been across the course of the HIV epidemic. We identified 39 studies. There was a geographical shift with trials moving from the USA to Africa and Asia over time. We found that recent trials were conducted in areas heavily affected by cryptococcal meningitis, but we did identify geographical areas and patient groups that have been underrepresented. We also found inequality within authorship that was skewed towards male researchers from high-income countries. These findings outline areas for our discipline to focus on. We can also use this study as a benchmark from which to monitor our progress over time. This is a broad methodology that could be adopted and adapted by other research groups.

The Lived Experience Of Participants in an African RandomiseD trial (LEOPARD): protocol for an in-depth qualitative study within a multisite randomised controlled trial for HIV-associated cryptococcal meningitis

INTRODUCTION

Individuals recruited into clinical trials for life-threatening illnesses are particularly vulnerable. This is especially true in low-income settings. The decision to enrol may be influenced by existing inequalities, poor healthcare infrastructure and fear of death. Where patients are confused or unconscious the responsibility for this decision falls to relatives. This qualitative study is nested in the ongoing AMBIsome Therapy Induction OptimisatioN (AMBITION) Trial. AMBITION is recruiting participants from five countries in sub-Saharan Africa and is trialling a novel treatment approach for HIV-associated cryptococcal meningitis, an infection known to affect brain function. We aim to learn from the experiences of participants, relatives and researchers involved in AMBITION.

METHODS AND ANALYSIS

We will collect data through in-depth interviews with trial participants and the next of kin of participants who were confused at enrolment and therefore provided surrogate consent. Data will be collected in Gaborone, Botswana; Kampala, Uganda and Harare, Zimbabwe. Interviews will follow a narrative approach including participatory drawing of participation timelines. This will be supplemented by direct observation of the research process at each of the three recruiting hospitals. Interviews will also take place with researchers from the African and European institutions that form the partnership through which the trial is administered. Interviews will be transcribed verbatim, translated (if necessary) and organised thematically for narrative analysis.

ETHICS AND DISSEMINATION

This study has been approved by the Health Research Development Committee, Gaborone (Reference: HPDME:13/18/1); Makerere School of Health Sciences Institutional Review Board, Kampala (Reference: 2019-061); University of Zimbabwe Joint Research Ethics Committee, Harare (Reference: 219/19), and the London School of Hygiene and Tropical Medicine (Reference: 17957). Study findings will be shared with research participants from the sites, key stakeholders at each research institution and ministries of health to help inform the development and implementation of future trials. The findings of this study will be published in journals and presented at academic meetings.

TRIAL REGISTRATION

Registered at www.clinicaltrials.gov:NCT04296292.

The prevalence of laboratory-confirmed Pneumocystis jirovecii in HIV-infected adults in Africa: A systematic review and meta-analysis

BACKGROUND

The epidemiology of Pneumocystis jirovecii, known to colonize the respiratory tract and cause a life-threatening HIV-associated pneumonia (PCP), is poorly described in Africa. We conducted a systematic review to evaluate P. jirovecii prevalence in African HIV-positive adults with or without respiratory symptoms.

METHODS

We searched Medline, Embase, Cochrane library, Africa-Wide, and Web of Science for studies employing PCR and/or microscopy for P. jirovecii detection in respiratory samples from HIV-positive adults in Africa between 1995 and 2020. Prevalence with respiratory symptoms was pooled using random-effect meta-analysis, and stratified by laboratory method, sample tested, study setting, CD4 count, and trimethoprim/sulfamethoxazole prophylaxis. Colonization prevalence in asymptomatic adults and in adults with non-PCP respiratory disease was described, and quantitative PCR (qPCR) thresholds to distinguish colonization from microscopy-confirmed PCP reviewed.

RESULTS

Thirty-two studies were included, with 27 studies (87%) at high risk of selection bias. P. jirovecii was detected in 19% [95% confidence interval (CI): 12-27%] of 3583 symptomatic and in 9% [95% CI: 0-45%] of 140 asymptomatic adults. Among symptomatic adults, prevalence was 22% [95% CI: 12-35%] by PCR and 15% [95% CI: 9-23%] by microscopy. Seven percent of 435 symptomatic adults had PCR-detected Pneumocystis colonization without evidence of PCP [95% CI: 5-10%, four studies]. One study established a qPCR cutoff of 78 copies/5μl of DNA in 305 induced sputum samples to distinguish Pneumocystis colonization from microscopy-confirmed PCP.

CONCLUSION

Despite widened access to HIV services, P. jirovecii remains common in Africa. Prevalence estimates and qPCR-based definitions of colonization are limited, and overall quality of studies is low.

Using a dual antibody point-of-care test with visual and digital reads to diagnose syphilis among people living with HIV in Botswana

Syphilis data from low- and middle-income countries are lacking due to limited testing. Point-of-care tests (POCTs) have been promoted to expand testing but previously only included treponemal tests, which cannot distinguish active from past infection. We aimed to assess the feasibility of using a combined treponemal and non-treponemal POCT in HIV clinic patients in Gaborone, Botswana, and estimate syphilis prevalence in our clinic sample using this approach. We recruited 390 non-pregnant patients. Participants underwent a combined treponemal and non-treponemal POCT (Dual Path Platform (DPP®) Syphilis Screen and Confirm Assay (Chembio Diagnostic Systems)) on finger-prick blood sample and a questionnaire. Median age 45 years, 30% men, median CD4 count 565 cells/μL, and 91% had an HIV viral load <400 copies/mL. Five participants had active syphilis (1.3%, 95% CI 0.5–3.0%) and 64 had previous syphilis (16.4%, 95% CI 13.0–20.4%) using the DPP POCT. There was a reasonable level of agreement between digital and visual reading of the POCT (kappa statistic of 0.81); however, visual reading missed three active infections (60%). The level of active syphilis was similar to local antenatal data. The DPP POCT led to five participants with active syphilis being diagnosed and starting same-day treatment. The digital reader should be used.

HIV-1C env and gag Variation in the Cerebrospinal Fluid and Plasma of Patients with HIV-Associated Cryptococcal Meningitis in Botswana

HIV-1 compartmentalization in reservoir sites remains a barrier to complete HIV eradication. It is unclear whether there is variation in HIV-1 env and gag between cerebrospinal fluid (CSF) and plasma of individuals with HIV-associated cryptococcal meningitis (CM). We compared HIV-1 env characteristics and the gag cytotoxic T-lymphocyte (CTL) escape mutations from CSF and plasma samples. Employing population-based Sanger sequencing, we sequenced HIV-1 env from CSF of 25 patients and plasma of 26 patients. For gag, 15 CSF and 21 plasma samples were successfully sequenced. Of these, 18 and 9 were paired env and gag CSF/plasma samples, respectively. There was no statistically significant difference in the proportion of CCR5-using strains in the CSF and plasma, (p = 0.50). Discordant CSF/plasma virus co-receptor use was found in 2/18 pairs (11.1%). The polymorphisms in the HIV-1 V3 loop were concordant between the two compartments. From the HIV-1 gag sequences, three pairs had discordant CTL escape mutations in three different epitopes of the nine analyzed. These findings suggest little variation in the HIV-1 env between plasma and CSF and that the CCR5-using strains predominate in both compartments. HIV-1 gag CTL escape mutations also displayed little variation in CSF and plasma suggesting similar CTL selective pressure.

Decolonising global health: transnational research partnerships under the spotlight

There are increasing calls to decolonise aspects of science, and global health is no exception. The decolonising global health movement acknowledges that global health research perpetuates existing power imbalances and aims to identify concrete ways in which global health teaching and research can overcome its colonial past and present. Using the context of clinical trials implemented through transnational research partnerships (TRPs) as a case study, this narrative review brings together perspectives from clinical research and social science to lay out specific ways in which TRPs build on and perpetuate colonial power relations. We will explore three core components of TRPs: participant experience, expertise and infrastructure, and authorship. By combining a critical perspective with recently published literature we will recommend specific ways in which TRPs can be decolonised. We conclude by discussing decolonising global health as a potential practice and object of research. By doing this we intend to frame the decolonising global health movement as one that is accessible to everyone and within which we can all play an active role.

Differences in human immunodeficiency virus-1C viral load and drug resistance mutation between plasma and cerebrospinal fluid in patients with human immunodeficiency virus-associated cryptococcal meningitis in Botswana

To determine effects of cryptococcal meningitis (CM) on human immunodeficiency virus (HIV)-1C cerebrospinal fluid (CSF) viral escape, CSF/plasma viral discordance, and drug resistance mutation (DRM) discordance between CSF and plasma compartments, we compared CSF and plasma viral load (VL) and DRMs in individuals with HIV-associated CM in Botswana.This cross-sectional study utilized 45 paired CSF/plasma samples from participants in a CM treatment trial (2014-2016). HIV-1 VL was determined and HIV-1 protease and reverse transcriptase genotyping performed. DRMs were determined using the Stanford HIV database. CSF viral escape was defined as HIV-1 ribonucleic acid ≥0.5 log10 higher in CSF than plasma and VL discordance as CSF VL > plasma VL.HIV-1 VL was successfully measured in 39/45 pairs, with insufficient sample volume in 6; 34/39 (87.2%) participants had detectable HIV-1 in plasma and CSF, median 5.1 (interquartile range: 4.7-5.7) and 4.6 (interquartile range:3.7-4.9) log10 copies/mL, respectively (P≤.001). CSF viral escape was present in 1/34 (2.9%) and VL discordance in 6/34 (17.6%). Discordance was not associated with CD4 count, antiretroviral status, fungal burden, CSF lymphocyte percentage nor mental status. Twenty-six of 45 (57.8%) CSF/plasma pairs were successfully sequenced. HIV-1 DRM discordance was found in 3/26 (11.5%); 1 had I84IT and another had M46MI in CSF only. The third had K101E in plasma and V106 M in CSF.Our findings suggest that HIV-1 escape and DRM discordance may occur at lower rates in participants with advanced HIV-disease and CM compared to those with HIV associated neurocognitive impairment.

Cryptococcal meningitis: a review of cryptococcal antigen screening programs in Africa

INTRODUCTION

Cryptococcal meningitis remains a significant contributor to AIDS-related mortality despite widened access to antiretroviral therapy. Cryptococcal antigen (CrAg) can be detected in the blood prior to development of meningitis. Development of highly sensitive and specific rapid diagnostic CrAg tests has helped facilitate the adoption of CrAg screening programs in 19 African countries.

AREAS COVERED

The biological rationale for CrAg screening and the programmatic strategies for its implementation are reviewed. We describe the approach to the investigation of patients with cryptococcal antigenemia and the importance of lumbar puncture to identify individuals who may have cryptococcal meningitis in the absence of symptoms. The limitations of current treatment recommendations and the potential role of newly defined combination antifungal therapies are discussed. A literature review was conducted using a broad database search for cryptococcal antigen screening and related terms in published journal articles dating up to December 2019. Conference abstracts, publicly available guidelines, and project descriptions were also incorporated.

EXPERT OPINION

As we learn more about the risks of cryptococcal antigenemia, it has become clear that the current management paradigm is inadequate. More intensive investigation and management are required to prevent the development of cryptococcal meningitis and reduce mortality associated with cryptococcal antigenemia.

Engineered BRET-Based Biologic Light Sources Enable Spatiotemporal Control over Diverse Optogenetic Systems

Light-inducible optogenetic systems offer precise spatiotemporal control over a myriad of biologic processes. Unfortunately, current systems are inherently limited by their dependence on external light sources for their activation. Further, the utility of laser/LED-based illumination strategies are often constrained by the need for invasive surgical procedures to deliver such devices and local heat production, photobleaching and phototoxicity that compromises cell and tissue viability. To overcome these limitations, we developed a novel BRET-activated optogenetics (BEACON) system that employs biologic light to control optogenetic tools. BEACON is driven by self-illuminating bioluminescent-fluorescent proteins that generate "spectrally tuned" biologic light via bioluminescence resonance energy transfer (BRET). Notably, BEACON robustly activates a variety of commonly used optogenetic systems in a spatially restricted fashion, and at physiologically relevant time scales, to levels that are achieved by conventional laser/LED light sources.

Mortality from HIV-associated meningitis in sub-Saharan Africa: a systematic review and meta-analysis

INTRODUCTION

HIV-associated cryptococcal, TB and pneumococcal meningitis are the leading causes of adult meningitis in sub-Saharan Africa (SSA). We performed a systematic review and meta-analysis with the primary aim of estimating mortality from major causes of adult meningitis in routine care settings, and to contrast this with outcomes from clinical trial settings.

METHODS

We searched PubMed, EMBASE and the Cochrane Library for published clinical trials (defined as randomized-controlled trials (RCTs) or investigator-managed prospective cohorts) and observational studies that evaluated outcomes of adult meningitis in SSA from 1 January 1990 through 15 September 2019. We performed random effects modelling to estimate pooled mortality, both in clinical trial and routine care settings. Outcomes were stratified as short-term (in-hospital or two weeks), medium-term (up to 10 weeks) and long-term (up to six months).

RESULTS AND DISCUSSION

Seventy-nine studies met inclusion criteria. In routine care settings, pooled short-term mortality from cryptococcal meningitis was 44% (95% confidence interval (95% CI):39% to 49%, 40 studies), which did not differ between amphotericin (either alone or with fluconazole) and fluconazole-based induction regimens, and was twofold higher than pooled mortality in clinical trials using amphotericin based treatment (21% (95% CI:17% to 25%), 17 studies). Pooled short-term mortality of TB meningitis was 46% (95% CI: 33% to 59%, 11 studies, all routine care). For pneumococcal meningitis, pooled short-term mortality was 54% in routine care settings (95% CI:44% to 64%, nine studies), with similar mortality reported in two included randomized-controlled trials. Few studies evaluated long-term outcomes.

CONCLUSIONS

Mortality rates from HIV-associated meningitis in SSA are very high under routine care conditions. Better strategies are needed to reduce mortality from HIV-associated meningitis in the region.

On Command Drug Delivery via Cell-Conveyed Phototherapeutics

Herein, the use of red blood cells (RBCs) as carriers of cytoplasmically interned phototherapeutic agents is described. Photolysis promotes drug release from the RBC carrier thereby providing the means to target specific diseased sites. This strategy is realized with a vitamin B12-taxane conjugate (B12-TAX), in which the drug is linked to the vitamin via a photolabile CoC bond. The conjugate is introduced into mouse RBCs (mRBCs) via a pore-forming/pore-resealing procedure and is cytoplasmically retained due to the membrane impermeability of B12. Photolysis separates the taxane from the B12 cytoplasmic anchor, enabling the drug to exit the RBC carrier. A covalently appended Cy5 antenna sensitizes the conjugate (Cy5-B12-TAX) to far red light, thereby circumventing the intense light absorbing properties of hemoglobin (350-600 nm). Microscopy and imaging flow cytometry reveal that Cy5-B12-TAX-loaded mRBCs act as drug carriers. Furthermore, intravital imaging of mice furnish a real time assessment of circulating phototherapeutic-loaded mRBCs as well as evidence of the targeted photorelease of the taxane upon photolysis. Histopathology confirms that drug release occurs in a well resolved spatiotemporal fashion. Finally, acoustic angiography is employed to assess the consequences of taxane release at the tumor site in Nu/Nu-tumor-bearing mice.

Compartmentalized cAMP Generation by Engineered Photoactivated Adenylyl Cyclases

Because small-molecule activators of adenylyl cyclases (AC) affect ACs cell-wide, it is challenging to explore the signaling consequences of AC activity emanating from specific intracellular compartments. We explored this issue using a series of engineered, optogenetic, spatially restricted, photoactivable adenylyl cyclases (PACs) positioned at the plasma membrane (PM), the outer mitochondrial membrane (OMM), and the nucleus (Nu). The biochemical consequences of brief photostimulation of PAC is primarily limited to the intracellular site occupied by the PAC. By contrast, sustained photostimulation results in distal cAMP signaling. Prolonged cAMP generation at the OMM profoundly stimulates nuclear protein kinase (PKA) activity. We have found that phosphodiesterases 3 (OMM and PM) and 4 (PM) modulate proximal (local) cAMP-triggered activity, whereas phosphodiesterase 4 regulates distal cAMP activity as well as the migration of PKA's catalytic subunit into the nucleus.

Laser Light Therapy in Inflammatory, Musculoskeletal, and Autoimmune Disease

PURPOSE OF REVIEW

The goal of this review is to summarize the field to date and to discuss strengths and limitations of low-level laser (light) therapy (LLLT) for the future investigation as a treatment of inflammatory disease.

RECENT FINDINGS

LLLT is a promising therapeutic, particularly for those diseases of skin and joints because they are most accessible to treatment. Indeed, the known mechanisms of LLLT support its use for anti-inflammatory purposes, as well as stimulation of tissue growth and repair. Although the standard of care for the majority of inflammatory diseases is immunosuppressive agents such as corticosteroids with undesirable toxicities, LLLT offers a unique approach by being non-invasive and incurring minimal side effects. It is also relatively inexpensive and accessible and even has the possibility to be patient directed at home. There is evidence that LLLT is able to modulate the immune system at the skin and joint, and it has been shown to be efficacious in humans by affecting bacterial colonization as it may pertain to chronic rhinosinusitis. However, there is variability in the methods of laser application as well as a lack of evidence for laser type, dose-ranging studies, and wavelength selection that create barriers to the implementation of LLLT without further more rigorous and standardized study. The heterogeneity makes it difficult to draw strong conclusions about the efficacy of LLLT and its mechanisms.

Design, construction, and validation of optogenetic proteins

Cellular optogenetics employs light-regulated, genetically encoded protein actuators to perturb cellular signaling with unprecedented spatial and temporal control. Here, we present a potentially generalized approach for transforming a given protein of interest (POI) into an optogenetic species. We describe the rational and methods by which we developed three different optogenetic POIs utilizing the Cry2-Cib photodimerizing pair. The process pipeline is highlighted by (1) developing a low level, constitutively active POI that is independent of endogenous regulation, (2) fusion of the mutant protein of interest to an optogenetic photodimerizing system, and (3) light-mediated recruitment of the light-responsive POI to specific subcellular regions.

Optogenetic perturbation of the biochemical pathways that control cell behavior

Optogenetic tools provide a level of spatial and temporal resolution needed to shed new light on dynamic intercellular processes. In this chapter we outline specific protocols for applying these tools to cell motility (optogenetic cofilin), apoptosis [optogenetic Bcl-like protein 4 (Bax)], and protein kinase-mediated signaling pathways [optogenetic cAMP-dependent protein kinase (PKA)]. The activity of these optogenetic species is regulated by the light-mediated dimerization of a cryptochrome/Cib protein pair, which controls the intracellular positioning of the protein of interest. The light induced recruitment of cofilin to the cytoskeleton is utilized for directed migration studies and filopodial dynamics. Light-triggered migration of Bax to the outer mitochondrial membrane induces cellular collapse and eventual apoptosis. Finally, the light-mediated movement of PKA to specific intracellular compartments offers the means to assess the consequences of PKA activity in a site-specific fashion via phosphoproteomic analysis.

Selection and optimization of enzyme reporters for chemical cytometry

Chemical cytometry, sensitive analytical measurements of single cells, reveals inherent heterogeneity of cells within a population which is masked or averaged out when using bulk analysis techniques. A particular challenge of chemical cytometry is the development of a suitable reporter or probe for the desired measurement. These reporters must be sufficiently specific for measuring the desired process; possess a lifetime long enough to accomplish the measurement; and have the ability to be loaded into single cells. This chapter details our approach to rationally design and improve peptide substrates as reporters of enzyme activity utilizing chemical cytometry. This method details the iterative approach used to design, characterize, and identify a peptidase-resistant peptide reporter which acts as a kinase substrate within intact cells. Small-scale, rationally designed peptide libraries are generated to rapidly and economically screen candidate reporter peptides for substrate suitability and peptidase resistance. Also detailed are strategies to characterize and validate the designed reporters by determining kinetic parameters, intracellular substrate specificity, resistance to degradation by intracellular peptidases, and behavior within lysates and intact cells.

Dasatinib Is Preferentially Active in the Activated B-Cell Subtype of Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease, and at least one-third of its patients relapse after treatment with the current chemotherapy regimen, R-CHOP. By gene-expression profiling, patients with DLBCL can be categorized into two clinically relevant subtypes: activated B-cell (ABC) and germinal center B-cell (GCB) DLBCL. Patients with the ABC subtype have a worse prognosis than those with GCB, and the subtype is defined by chronic, over-active signaling through the B-cell receptor and NF-κB pathways. We examined the effects of the Src family kinase (SFK) inhibitor dasatinib in a panel of ABC and GCB DLBCL cell lines and found that the former are much more sensitive to dasatinib than the latter. However, using multiplexed inhibitor bead coupled to mass spectrometry (MIB/MS) kinome profiling and Western blot analysis, we found that both subtypes display inhibition of the SFKs in response to dasatinib after both short- and long-term treatment. The MIB/MS analyses revealed that several cell-cycle kinases, including CDK4, CDK6, and the Aurora kinases, are down-regulated by dasatinib treatment in the ABC, but not in the GCB, subtype. The present findings have potential implications for the clinical use of dasatinib for the treatment of ABC DLBCL, either alone or in combination with other agents.

AMBIsome Therapy Induction OptimisatioN (AMBITION): High Dose AmBisome for Cryptococcal Meningitis Induction Therapy in sub-Saharan Africa: Study Protocol for a Phase 3 Randomised Controlled Non-Inferiority Trial

BACKGROUND

Cryptococcal meningitis (CM) is a major cause of mortality in HIV programmes in Africa despite increasing access to antiretroviral therapy (ART). Mortality is driven in part by limited availability of amphotericin-based treatment, drug-induced toxicities of amphotericin B deoxycholate and prolonged hospital admissions. A single, high-dose of liposomal amphotericin (L-AmB, Ambisome) on a fluconazole backbone has been reported as non-inferior to 14 days of standard dose L-AmB in reducing fungal burden. This trial examines whether single, high-dose L-AmB given with high-dose fluconazole and flucytosine is non-inferior to a seven-day course of amphotericin B deoxycholate plus flucytosine (the current World Health Organization [WHO] recommended treatment regimen).

METHODS

An open-label phase III randomised controlled non-inferiority trial conducted in five countries in sub-Saharan Africa: Botswana, Malawi, South Africa, Uganda and Zimbabwe. The trial will compare CM induction therapy with (1) a single dose (10 mg/kg) of L-AmB given with 14 days of fluconazole (1200 mg/day) and flucytosine (100 mg/kg/day) to (2) seven days amphotericin B deoxycholate (1 mg/kg/day) given alongside seven days of flucytosine (100 mg/kg/day) followed by seven days of fluconazole (1200 mg/day). The primary endpoint is all-cause mortality at ten weeks with a non-inferiority margin of 10% and 90% power. Secondary endpoints are early fungicidal activity, proportion of grade III/IV adverse events, pharmacokinetic parameters and pharmacokinetic/pharmacodynamic associations, health service costs, all-cause mortality within the first two and four weeks, all-cause mortality within the first ten weeks (superiority analysis) and rates of CM relapse, immune reconstitution inflammatory syndrome and disability at ten weeks. A total of 850 patients aged ≥ 18 years with a first episode of HIV-associated CM will be enrolled (425 randomised to each arm). All patients will be followed for 16 weeks. All patients will receive consolidation therapy with fluconazole 800 mg/day to complete ten weeks of treatment, followed by fluconazole maintenance and ART as per local guidance.

DISCUSSION

A safe, sustainable and easy to administer regimen of L-AmB that is non-inferior to seven days of daily amphotericin B deoxycholate therapy may reduce the number of adverse events seen in patients treated with amphotericin B deoxycholate and shorten hospital admissions, providing a highly favourable and implementable alternative to the current WHO recommended first-line treatment.

TRIAL REGISTRATION

ISRCTN, ISRCTN72509687 . Registered on 13 July 2017.

High Mortality in HIV-Associated Cryptococcal Meningitis Patients Treated With Amphotericin B-Based Therapy Under Routine Care Conditions in Africa

BACKGROUND

Cryptococcal meningitis (CM) causes 10%-20% of HIV-related deaths in Africa. Due to limited access to liposomal amphotericin and flucytosine, most African treatment guidelines recommend amphotericin B deoxycholate (AmB-d) plus high-dose fluconazole; outcomes with this treatment regimen in routine care settings have not been well described.

METHODS

Electronic national death registry data and computerized medical records were used to retrospectively collect demographic, laboratory, and 1-year outcome data from all patients with CM between 2012 and 2014 at Botswana's main referral hospital, when recommended treatment for CM was AmB-d 1 mg/kg/d plus fluconazole 800 mg/d for 14 days. Cumulative survival was estimated at 2 weeks, 10 weeks, and 1 year.

RESULTS

There were 283 episodes of CM among 236 individuals; 69% (163/236) were male, and the median age was 36 years. All patients were HIV-infected, with a median CD4 count of 39 cells/mm3. Two hundred fifteen person-years of follow-up data were captured for the 236 CM patients. Complete outcome data were available for 233 patients (99%) at 2 weeks, 224 patients (95%) at 10 weeks, and 219 patients (93%) at 1 year. Cumulative mortality was 26% (95% confidence interval [CI], 20%-32%) at 2 weeks, 50% (95% CI, 43%-57%) at 10 weeks, and 65% (95% CI, 58%-71%) at 1 year.

CONCLUSIONS

Mortality rates following HIV-associated CM treated with AmB-d and fluconazole in a routine health care setting in Botswana were very high. The findings highlight the inadequacies of current antifungal treatments for HIV-associated CM and underscore the difficulties of administering and monitoring intravenous amphotericin B deoxycholate therapy in resource-poor settings.

An Integrated Chemical Cytometry Method: Shining a Light on Akt Activity in Single Cells

Tools to evaluate oncogenic kinase activity in small clinical samples have the power to guide precision medicine in oncology. Existing platforms have demonstrated impressive insights into the activity of protein kinases, but these technologies are unsuitable for the study of kinase behavior in large numbers of primary human cells. To address these limitations, we developed an integrated analysis system that utilizes a light-programmable, cell-permeable reporter deliverable simultaneously to many cells. The reporter's ability to act as a substrate for Akt, a key oncogenic kinase, was masked by a 2-4,5-dimethoxy 2-nitrobenzyl (DMNB) moiety. Upon exposure to ultraviolet light and release of the masking moiety, the substrate sequence enabled programmable reaction times within the cell cytoplasm. When coupled to automated single-cell capillary electrophoresis, statistically significant numbers of primary human cells were readily evaluated for Akt activity.

Design and Application of Sensors for Chemical Cytometry

The bulk cell population response to a stimulus, be it a growth factor or a cytotoxic agent, neglects the cell-to-cell variability that can serve as a friend or as a foe in human biology. Biochemical variations among closely related cells furnish the basis for the adaptability of the immune system but also act as the root cause of resistance to chemotherapy by tumors. Consequently, the ability to probe for the presence of key biochemical variables at the single-cell level is now recognized to be of significant biological and biomedical impact. Chemical cytometry has emerged as an ultrasensitive single-cell platform with the flexibility to measure an array of cellular components, ranging from metabolite concentrations to enzyme activities. We briefly review the various chemical cytometry strategies, including recent advances in reporter design, probe and metabolite separation, and detection instrumentation. We also describe strategies for improving intracellular delivery, biochemical specificity, metabolic stability, and detection sensitivity of probes. Recent applications of these strategies to small molecules, lipids, proteins, and other analytes are discussed. Finally, we assess the current scope and limitations of chemical cytometry and discuss areas for future development to meet the needs of single-cell research.

Cellular Cyborgs: On the Precipice of a Drug Delivery Revolution

Cell-based drug delivery systems offer the prospect of biocompatibility, large-loading capacity, long in vivo lifespan, and active targeting of diseased sites. However, these opportunities are offset by an array of challenges, including safeguarding the integrity of the drug cargo and the cellular host, as well as ensuring that drug release occurs at the appropriate time and place. Emerging strategies that address these, and related, issues, are described herein.

Design and Profiling of a Subcellular Targeted Optogenetic cAMP-Dependent Protein Kinase

Although the cAMP-dependent protein kinase (PKA) is ubiquitously expressed, it is sequestered at specific subcellular locations throughout the cell, thereby resulting in compartmentalized cellular signaling that triggers site-specific behavioral phenotypes. We developed a three-step engineering strategy to construct an optogenetic PKA (optoPKA) and demonstrated that, upon illumination, optoPKA migrates to specified intracellular sites. Furthermore, we designed intracellular spatially segregated reporters of PKA activity and confirmed that optoPKA phosphorylates these reporters in a light-dependent fashion. Finally, proteomics experiments reveal that light activation of optoPKA results in the phosphorylation of known endogenous PKA substrates as well as potential novel substrates.