Evaluation of PIMATM CD4 System for Decentralization of Immunological Monitoring of HIV-Infected Patients in Senegal

Prevalence and predictors of Aspergillus seropositivity and chronic pulmonary aspergillosis in an urban tertiary hospital in Sierra Leone: A cross-sectional study

BACKGROUND

In the World Health Organization Global Tuberculosis (TB) Report 2022, 37% of pulmonary TB patients were clinically diagnosed and thus many people were treated for TB without evidence of the disease. Probably the most common TB misdiagnosis is chronic pulmonary aspergillosis (CPA). In this study, we aimed to assess the prevalence and predictors of Aspergillus seropositivity and CPA in patients with chronic respiratory symptoms in an urban tertiary hospital in Sierra Leone.

METHODOLOGY/PRINCIPAL FINDINGS

We used a cross-sectional study design to recruit adults (≥18 years) from the Chest Clinic of Connaught Hospital, Freetown between November 2021 and July 2022. Aspergillus antibody was detected using LDBio Aspergillus IgM/IgG. Logistic regression was performed to assess the independent predictors of Aspergillus seropositivity and CPA. Of the 197 patients with chronic respiratory symptoms, 147 (74.6%) were male. Mean age was 47.1 ± 16.4 years. More than half (104, 52.8%) had been diagnosed with TB in the past, while 53 (26.9%) were on TB treatment at the time of recruitment. Fifty-two (26.4%) patients were HIV positive, 41 (20.8%) were seropositive for Aspergillus and 23 (11.6%) had CPA, 2 (3.8%) with current TB and 18 (17.3%) with past TB. Common radiologic abnormalities reported were localized fibrotic changes 62 (31.5%), consolidation 54 (27.4%), infiltrates 46 (23.4%), hilar adenopathy 40 (20.3%) and pleural effusion 35 (17.85) and thickening 23 (11.7%). Common symptoms were weight loss 144 (73.1%), cough 135 (68.5%), fever 117 (59.4%) and dyspnea 90 (45.7%). Current or past TB infection {aOR 3.52, 95% CI (1.46, 8.97); p = 0.005} was an independent predictor of Aspergillus seropositivity and CPA.

CONCLUSIONS/SIGNIFICANCE

We report a high prevalence of Aspergillus antibody seropositivity and CPA, underscoring the need to integrate the prevention and management of pulmonary fungal infections with TB services and asthma care in order to reduce unnecessary morbidity and mortality.

Prevalence of hepatitis B surface antigen and serological markers of other endemic infections in HIV-infected children, adolescents and pregnant women in Sierra Leone: A cross-sectional study

OBJECTIVE

To assess the prevalence of serological markers of HBV and endemic acute and chronic infections (HAV, HCV, CMV, HTLV-1/2 and syphilis) in HIV-infected children, adolescents and pregnant women in Sierra Leone.

METHOD

We conducted a cross-sectional study at the national children's and women's hospitals in Freetown. Logistic regression was used to assess predictors of HBsAg positivity.

RESULTS

183 HIV-infected participants were enrolled, comprising children (n = 88), adolescents (n = 47) and pregnant women (n = 48). All participants (100%) were CMV IgG-positive, while 56.8%, 93.6% and 100% of children, adolescents and pregnant women, respectively, were HAV IgG-positive. The prevalence of HCV, HTLV-1/2 and syphilis were <4%. HBV markers were distributed as follows-children: HBsAg (2.3%), HBeAg (0%), anti-HBc (5.7%); adolescents: HBsAg (17.0%), HBeAg (6.4%), anti-HBc (27.7%); and pregnant women: HBsAg (18.8%), HBeAg (4.2%), anti-HBc (77.1%). Age >10 years, i.e., being born pre-2009 before implementation of routine hepatitis B immunization (aOR 5.05 [1.18-21.28]; p = 0.029) and CD4 count <350 cells/mm³ (aOR 3.97 [1.07-14.71]; p = 0.039) predicted HBsAg positivity.

CONCLUSION

A high burden of chronic HBV and other endemic infections was observed among HIV-infected patients born pre-2009 before implementation of routine HBV immunization in Sierra Leone, warranting targeted screening and immunization of this high-risk population.

Preclinical Assessment of a Cartridge-Based Flow-Through Assay for Determination of Adult CD4 T-Cell Count

Background:

Despite the emphasis on viral load testing, current HIV testing guidelines consider CD4 T-cell count measurement as an important criterion for assessing disease progression, making decisions about anti-retroviral therapy regime changes, and treating HIV infected individuals with opportunistic infections. The CD4 counting by established methods (e.g., flow cytometry) presents challenges not only in resource-scarce settings due to cost and lack of skilled technicians but also in resource-rich areas where it is limited to centralized facilities.

Objective:

Current options for Point-Of-Care (POC) CD4 enumeration are few and labor-intensive, prompting the need for newer technological methods that can overcome the aforementioned challenges.

Methods:

The novel and patented flow-through cell counting assay (FTCA) described previously (Bystryak et al., 2019) was developed further into a point-of-care CD4 testing system using a disposable cartridge device and a portable imaging instrument. A pilot study with ~100 samples using this device was conducted to assess the validity of FTCA as a POC test for the measurement of CD4 count.

Results:

The FTCA signal was found to be linear over a wide range (17 - 1540 cells/μL) of CD4 T-cell concentration. The FTCA method also exhibits a strong agreement with flow cytometry, with very low bias (− 7 cells/μL) towards CD4 count measurement.

Conclusion:

The cartridge-based FTCA method has great potential to be a fully quantitative method with low complexity, portability, low-cost, and wide applicability in clinical practice.

Causes of hospitalization and predictors of HIV-associated mortality at the main referral hospital in Sierra Leone: a prospective study

Background

HIV infection is a growing public health problem in Sierra Leone and the wider West Africa region. The countrywide HIV prevalence was estimated at 1.7% (67,000 people), with less than 30% receiving life-saving ART in 2016. Thus, HIV-infected patients tend to present to health facilities late, with high mortality risk.

Methods

We conducted a prospective study of HIV inpatients aged ≥15 years at Connaught Hospital in Freetown—the main referral hospital in Sierra Leone—from July through September 2017, to assess associated factors and predictors of HIV-related mortality.

Results

One hundred seventy-three HIV inpatients were included, accounting for 14.2% (173/1221) of all hospital admissions during the study period. The majority were female (59.5%, 70/173), median age was 34 years, with 51.4% (89/173) of them diagnosed with HIV infection for the first time during the current hospitalization. The most common admitting diagnoses were anemia (48%, 84/173), tuberculosis (24.3%, 42/173), pneumonia (17.3%, 30/173) and diarrheal illness (15.0%, 26/173). CD4 count was obtained in 64.7% (112/173) of patients, with median value of 87 cells/μL (IQR 25–266), and was further staged as severe immunosuppression: CD4 < 100 cells/μL (50%, 56/112); AIDS: CD4 < 200 cells/μL (69.6%, 78/112); and late-stage HIV disease: CD4 < 350 cells/μL (83%, 93/112). Fifty-two patients (30.1%, 52/173) died during hospitalization, 23% (12/52) of them within the first week. The leading causes of death were anemia (23.1%, 12/52), pneumonia (19.2%, 10/52), diarrheal illness (15.4%, 8/52) and tuberculosis (13.6%, 7/52). Neurological symptoms, i.e., loss of consciousness (p = 0.04) and focal limb weakness (p = 0.04); alcohol use (p = 0.01); jaundice (p = 0.02); cerebral toxoplasmosis (p = 0.01); and tuberculosis (p = 0.04) were significantly associated with mortality; however, only jaundice (AOR 0.11, 95% CI [0.02–0.65]; p = 0.01) emerged as an independent predictor of mortality.

Conclusion

HIV-infected patients account for a substantial proportion of admissions at Connaught Hospital, with a high morbidity and in-hospital mortality burden. These findings necessitate the implementation of specific measures to enhance early HIV diagnosis and expand treatment access to all HIV-infected patients in Sierra Leone.

A flow-through cell counting assay for point-of-care enumeration of CD4 T-cells

CD4 T-cell count is a priority for staging HIV disease and guiding clinical management as part of HIV care. Conventional CD4 T-cell enumeration methods based on flow cytometry are expensive, require well-trained personnel, and are challenging to use in rural, resource-scarce areas. A simple CD4 T-cell count test that can be used at point-of care, the Flow-Through cell Counting Assay (FTCA), is described in this article. The FTCA is based on the use of: 1) a special membrane that selectively retains white blood cells (WBCs); 2) a sample delivery system; and 3) optical signal detection. To show the feasibility of the FTCA, a proof-of-concept prototype of the FTCA cassette and digital camera or handheld reflectance meter were used for obtaining quantitative assay results within 30 min. The results show that the FTCA allows for quantitative enumeration of CD4 T-cells in the clinically relevant range of CD4 T-cell concentrations. The advantages of the FTCA technology, including simplicity, short analysis time, and portability, suggest that FTCA has great potential for use in clinical practice and wide applicability for other cell-based diagnostic tests.

High Prevalence of Late-Stage Disease in Newly Diagnosed Human Immunodeficiency Virus Patients in Sierra Leone

A high prevalence of late-stage disease (75.4%) and severe immunosuppression (23.3%) was observed in 155 newly diagnosed human immunodeficiency virus patients in Freetown, Sierra Leone during August to November 2017. Within the late-stage diagnosis group, a significantly high proportion of patients reported fever (84.2% vs 65.2%; P = .01), weight loss (82.2% vs 63.5%; P = .01), and malaise (89.7% vs 71.7%; P = .05). Fever was identified as the only independent predictor of late-stage disease in this study.

Performance evaluation of the touchscreen-based Muse™ Auto CD4/CD4% single-platform system for CD4 T cell numeration in absolute number and in percentage using blood samples from children and adult patients living in the Central African Republic

Background

The new microcapillary and fluorescence-based EC IVD-qualified Muse™ Auto CD4/CD4% single-platform assay (EMD Millipore Corporation, Merck Life Sciences, KGaA, Darmstadt, Germany) for CD4 T cell numeration in absolute number and in percentage was evaluated using Central African patients’ samples compared against the reference EC IVD-qualified BD FACSCount (Becton–Dickinson, USA) flow cytometer.

Methods

EDTA-blood samples from 124 adults, 10 adolescents, 13 children and 3 infants were tested in parallel at 2 reference laboratories in Bangui.

Results

The Muse™ technique was highly reproducible, with low intra- and inter-run variabilities less than 15%. CD4 T cell counts of Muse™ and BD FACSCount in absolute number and percentage were highly correlated (r² = 0.99 and 0.98, respectively). The mean absolute bias between Muse™ and BD FACSCount cells in absolute number and percentage were −5.91 cells/µl (95% CI −20.90 to 9.08) with limits of agreement from −77.50 to 202.40 cells/µl, and +1.69 %CD4 (95% CI ±1.29 to +2.09), respectively. The percentages of outliers outside the limits of agreement were nearly similar in absolute number (8%) and percentage (10%). CD4 T cell counting by Muse™ allowed identifying the majority of individuals with CD4 T cell <200, <350 or <750 cells/µl corresponding to the relevant thresholds of therapeutic care, with sensitivities of 95.5–100% and specificities of 83.9–100%.

Conclusions

The Muse™ Auto CD4/CD4% Assay analyzer is a reliable alternative flow cytometer for CD4 T lymphocyte enumeration to be used in routine immunological monitoring according to World Health Organization recommendations in HIV-infected adults as well as children living in resource-constrained settings.