Mycobacterium and the coat of many lipids

Pathogenic Mycobacterium reside inside vacuoles in their host macrophages. These vacuoles fail to fuse with lysosomes yet interact with early endosomes. Glycoconjugates released by the intracellular bacilli traffic through the host cell and are released through exocytosis. These molecules represent both antigens for immune recognition and modulators of immune function. The molecules play key roles in the induction and maintenance of the granuloma, a tissue response that limits bacterial spread yet ensures persistence of the infection

Endothelial dysfunction and carotid atherosclerosis in Malawian adults: A cross-sectional study

Background and objective In sub-Saharan Africa, data on prevalence, risk factors and pathobiology of carotid atherosclerosis are scarce. We aimed to investigate the relationship between biomarkers of endothelial dysfunction and carotid atherosclerosis. Methods Carotid ultrasound was performed in 66 patients. Plasma concentration of ICAM-1, PAI-1, VEGF, and soluble thrombomodulin were measured by ELISA. A univariable logistic regression analysis was performed to study the relationship between carotid atherosclerosis, biomarkers of endothelial dysfunction, and various demographic and clinical parameters of the participants. Results The mean age of the participants was 58.7 years (95% CI: 54.4–63.1). Carotid atherosclerosis was diagnosed in 39.4% (95% CI: 27.6–52.2). In the univariable logistic regression, the following factors were associated with carotid atherosclerosis: age > 45 years (OR = 12.0, 95% CI: 1.4–98.8, p = .02), hypertension (OR = 3.8, 95% CI: 1.2–12.1, p = .02), and high-level of soluble thrombomodulin (OR = 3.4, 95% CI: 1.2–10.0, p = .02). Conclusions There is an association between high levels of soluble thrombomodulin and carotid atherosclerosis in Malawian adults. Further studies with a larger sample size are needed to confirm our findings in other African populations

Human alveolar macrophages predominately express combined classical M1 and M2 surface markers in steady state.

Alveolar macrophages (AM) are critical to the homeostasis of the inflammatory environment in the lung. Differential expression of surface markers classifies macrophages to either classically (M1) or alternatively activated (M2). We investigated the phenotype of human alveolar macrophages (AM) in adults living in two different geographical locations: UK and Malawi. We show that the majority of AM express high levels of M1 and M2 markers simultaneously, with the M1/M2 phenotype being stable in individuals from different geographical locations. The combined M1/M2 features confer to AM a hybrid phenotype, which does not fit the classic macrophage classification. This hybrid phenotype may confer to alveolar macrophages an ability to quickly switch between M1 or M2 associated functions allowing for appropriate responses to stimuli and tissue environment

Heterogeneous loss of HIV transcription and proviral DNA from 8E5/LAV lymphoblastic leukemia cells revealed by RNA FISH:FLOW analyses

8E5/LAV cells harbor a single HIV provirus, and are used frequently to generate standards for HIV genome quantification. Using flow cytometry-based in situ mRNA hybridization validated by qPCR, we find that different batches of 8E5 cells contain varying numbers of cells lacking viral mRNA and/or viral genomes. These findings raise concerns for studies employing 8E5 cells for quantitation, and highlight the value of mRNA FISH and flow cytometry in the detection and enumeration of HIV-positive cells

A 34-Year-Old Man With a Neck Mass.

CASE PRESENTATION A 34-year-old man presented to Queen Elizabeth Central Hospital in Blantyre, Malawi with multiple enlarged right cervical lymph nodes. He had no associated constitutional symptoms. Fine-needle aspirate (FNA) of one of the lymph nodes was negative for acid-fast bacilli (AFB) by smear microscopy. The FNA specimen was not sent for histological examination. Mycobacterial culture and Xpert MTB/RIF were not available at the time. He tested positive for HIV but CD4 T-cell count was not requested at the time of HIV diagnosis, and he did not start antiretroviral therapy (ART) pending confirmation of the cause of lymphadenopathy. Excision biopsy of the lymph nodes was planned; however, the patient was lost to follow-up before the procedure was performed

Perceptions of Research Bronchoscopy in Malawian Adults with Pulmonary Tuberculosis: A Cross-Sectional Study

Bronchoscopy is an established research tool in Malawi, enabling collection of pulmonary samples for immunological, pharmacological, and microbiological studies. It is, however, an invasive clinical procedure that offers no direct benefit to volunteering participants when used in a research capacity alone, and thus informed consent is essential. This study aimed to explore TB patients’ understanding of research bronchoscopy, what would motivate them to participate in research bronchoscopy, and their concerns, in order to inform consenting processes for future clinical studies. We used a qualitative research design. Two focus group discussions were conducted with community members and TB patients to understand their perceptions of bronchoscopy. Transcripts were coded by multiple co-authors and thematic content analysis was used to analyse main findings. We found that Malawian patients with pulmonary TB were willing to participate in a study using research bronchoscopy for health assessment and access to improved healthcare. We identified information of value to potential participants when consenting to that may lessen some of the anxieties expressed by participants. Patient and public involvement is essential to improve informed consent and institutional trust

B cell, CD8 + T cell and gamma delta T cell infiltration alters alveolar immune cell homeostasis in HIV-infected Malawian adults

HIV infection is associated with increased risk to lower respiratory tract infections (LRTI). However, the impact of HIV infection on immune cell populations in the lung is not well defined. We sought to comprehensively characterise the impact of HIV infection on immune cell populations in the lung. : Twenty HIV-uninfected controls and 17 HIV-1 infected ART-naïve adults were recruited from Queen Elizabeth Central Hospital, Malawi. Immunophenotyping of lymphocyte and myeloid cell populations was done on bronchoalveolar lavage fluid and peripheral blood cells. : We found that the numbers of CD8 T cells, B cells and gamma delta T cells were higher in BAL fluid of HIV-infected adults compared to HIV-uninfected controls (all p<0.05). In contrast, there was no difference in the numbers of alveolar CD4 T cells in HIV-infected adults compared to HIV-uninfected controls (p=0.7065). Intermediate monocytes were the predominant monocyte subset in BAL fluid (HIV-, 63%; HIV+ 81%), while the numbers of classical monocytes was lower in HIV-infected individuals compared to HIV-uninfected adults (p=0.0006). The proportions of alveolar macrophages and myeloid dendritic cells was lower in HIV-infected adults compared to HIV-uninfected controls (all p<0.05). : Chronic HIV infection is associated with broad alteration of immune cell populations in the lung, but does not lead to massive depletion of alveolar CD4 T cells. Disruption of alveolar immune cell homeostasis likely explains in part the susceptibility for LRTIs in HIV-infected adults

“An increase in COVID-19 patients would be overwhelming”: A qualitative description of healthcare workers’ experiences during the first wave of COVID-19 (March 2020 to October 2020) at Malawi’s largest referral hospital.

Background:   COVID-19 is currently a global health threat. Healthcare workers are on the front-line of the COVID-19 outbreak response and therefore at heightened risk of infection. There is a dearth of evidence from Sub-Saharan Africa about healthcare worker experiences in managing COVID-19.  We have reported on healthcare worker responses, experiences, and perspectives on epidemic response strategies at Queen Elizabeth Central Hospital, Malawi’s largest referral hospital.   Methods  We conducted 39 face-to-face in-depth interviews with a purposively selected sample of healthcare workers during the first wave of COVID-19 in Malawi (March 2020 to October 2020). The study included healthcare workers who provided direct and indirect patient care.   Results  During the early phase of the first wave (March to May 2020), healthcare workers expressed concerns with inadequate working space, unconducive infrastructure, delayed and rushed training on the management of COVID-19, and lack of incentives. Additionally, the hospital had staff shortages and limited essential resources such as piped oxygen and personal protective equipment. This increased healthcare worker fears of contracting COVID-19 and they were less willing to volunteer at COVID-19 isolation units. Resource constraints and limited preparedness compromised the care pathway particularly with increased numbers of COVID-19 patients. By the peak of the first wave (June to August 2020) many of these issues had been resolved. The hospital provided refresher training courses, personal protective equipment became available, incentives were offered to healthcare workers working in COVID-19 units and piped oxygen was installed. Staff morale was boosted, and more staff were willing to work at the COVID-19 isolation centres.   Conclusion  Experiences of healthcare workers during the first wave of COVID-19 are critical for improving care in future COVID-19 waves. Response strategies in resource-constrained areas should prioritise timely training of staff, creation of adequate isolation areas, provision of adequate medical supplies and strengthening leadership

The significant gap between international standards and stroke management practices at Queen Elizabeth Central Hospital (Malawi): An audit report

Background The Queen Elizabeth Central Hospital (QECH) is preparing to set up the first stroke unit in Blantyre, Malawi. We conducted this audit to assess current stroke management practices and outcomes at QECH and identify priority areas for intervention. Methods From April to June 2018, we prospectively enrolled patients with acute stroke and collected data on clinical presentation, cardiovascular risk factors, investigations and interventions, in-hospital outcomes, and follow-up plans after discharge. The American Heart Association/American Stroke Association (AHA/ASA) guidelines were used as the standard of care for comparison. Results Fifty patients with acute stroke were enrolled (46% women, 54% men). The mean age was 63.1 years (95% CI: 59.7-66.6). The diagnosis of stroke was based on the World Health Organization criteria. The diagnosis was made within 24 hours of admission in 19 patients (38%). Acute revascularisation therapy was not available. Forty-eight patients (96%) had their vital signs checked at baseline and 140/90 mmHg in 34 patients (68%), including 4 with values >220/120 mmHg. Nine patients had an RBS >10 mmol/L and four received insulin. Prophylaxis for deep venous thrombosis was offered to 12 patients (24%). Aspiration pneumonia was reported in 16 patients (32%) and was the most common hospital complication. The mean duration of hospitalisation was 10.4 days (95% CI: 5.6-15.2), and case fatality was 18%. The modified Rankin scale at discharge was ≤2 in 32% of patients. Only four patients (8%) were transferred to a rehabilitation centre. At the time of discharge, only 32% of patients received education on stroke. Conclusion Acute stroke care is less than optimal in this setting. Simple interventions such as reducing the delay in making a stroke diagnosis, early swallow assessments, and closer monitoring of vital signs could make a significant difference in stroke outcome. Furthermore, treating cardiovascular risk factors and setting up health education programmes to improve secondary prevention represent key priorities

Circulating microparticles are increased amongst people presenting with HIV and advanced immune suppression in Malawi and correlate closely with arterial stiffness: a nested case control study [version 2; peer review: 2 approved, 1 approved with reservations]

BACKGROUND: We aim to investigate whether circulating microparticle (CMPs) subsets were raised amongst people presenting with a new diagnosis of HIV and advanced immune suppression in Malawi, and whether they associated with arterial stiffness. Methods: Microparticle characterisation and carotid femoral Pulse Wave Velocity (cfPWV) were carried out in a cohort of adults with a new HIV diagnosis and CD4 <100 cells/µL at 2 weeks post ART initiation. HIV uninfected controls were matched on age, systolic BP and diastolic BP in a 1:1 ratio. Circulating microparticles were identified from platelet poor plasma and stained for endothelial, leucocyte, monocyte and platelet markers. METHODS: Microparticle characterisation and carotid femoral Pulse Wave Velocity (cfPWV) were carried out in a cohort of adults with a new HIV diagnosis and CD4 <100 cells/µL at 2 weeks post ART initiation. HIV uninfected controls were matched on age, systolic BP and diastolic BP in a 1:1 ratio. Circulating microparticles were identified from platelet poor plasma and stained for endothelial, leucocyte, monocyte and platelet markers. RESULTS: The median (IQ) total CMP count for 71 participants was 1 log higher in HIV compared to those without (p<0.0001) and was associated with arterial stiffness (spearman rho 0.47, p<0.001). In adjusted analysis, every log increase in circulating particles showed a 20% increase in cfPWV (95% CI 4 – 40%, p=0.02). In terms of subsets, endothelial and platelet derived microparticles were most strongly associated with HIV. Endothelial derived E-selectin+ CMPs were 1.3log-fold higher and platelet derived CD42a+ CMPs were 1.4log-fold higher (both p<0.0001). Endothelial and platelet derived CMPs also correlated most closely with arterial stiffness [spearman rho: E-selectin+ 0.57 and CD42a 0.56, both p<0.0001). CONCLUSIONS: Circulating microparticles associate strongly with arterial stiffness among PLWH in Malawi. Endothelial and platelet microparticles are the predominant cell origin types, indicating that platelet driven endothelial dysfunction pathways warrant further investigation in HIV associated arterial stiffness