Although major house dust mite allergen (Der p 1) is carried mainly on large particles (>10 microm), standard bronchial challenge tests (BCT) use nebulizers that deliver smaller particles (sizes from 1 to 5 microm) and may therefore not reflect actual domestic exposure. The objective of this study was to evaluate the influence of particle size of Dermatophagoides pteronyssinus extract on bronchial response. Specific BCT were performed with different mass median aerodynamic diameters (MMAD): 1.1, 5.6, and 9.7 microm. Each of the 19 mite-sensitized patients underwent mite BCT three times, once with each nebulizer. IL-5 levels were assessed in induced sputum and blood samples. The PD(20) for Der p 1 differed substantially with particle size, with less Der p 1 (11.2 ng) needed to produce a PD(20) with the largest particles (9.7 microm), compared to 18.1 ng for the 5.6 microm particles and 142.5 ng for the 1.1 microm particles (p < 0.0001). Large particles also induced an early phase response significantly more often than small particles (100% vs. 63%). Although the late phase reaction (LPR) frequency was similar with all three particle sizes, lower mean oral corticosteroid doses were needed to treat LPR with the largest particles (23 mg), compared to the smaller particles, with 34 mg for the 5.6 microm particles and 51 mg for the 1.1 microm. The 1.1 microm particles produced a significantly greater increase in IL-5 concentrations in sputum and blood compared to the larger particles. Large particles clearly play a role in the immediate bronchial response in asthmatics sensitized to mites and, therefore, should be included in pharmacological studies in humans.
Background
An issue of particular concern is the impact of the 2019 novel coronavirus (2019 nCOV) on the people coinfected with the Human Immuno-deficiency Virus (HIV) and/or tuberculosis (TB). Unfortunately, this interaction has not been well explored in African despite the large proportion of these risk populations living with HIV and/or patients and/or tuberculosis (TB) in the African region. This study aims to design a research protocol for assessment of the impact of coronavirus disease 2019 (COVID-19) on these risk populations in response to COVID-19 strategic plans in Burkina Faso by generating serological, epidemiological, virological, clinical and socio-anthropological evidence-based data.
Methods
A multidisciplinary research will be conducted in the city of Bobo-Dioulasso, Burkina Faso using mixed methods. Data will be collected from a cohort of people living with HIV and/or TB patients in the city (i) to determine the proportion of people with specific antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using retrospective data ; (ii) to determine the proportion of people infected with Covid-19 and the dynamics of viral loads and antibodies in these people based on prospective data; (iii) to identify circulating SARS-COV-2 variants and novel biomarkers using prospective data ; (iv) to analyze perceptions, community experiences and response strategies during the public health emergencies imposed by COVID-19 through a qualitative study.
Discussion
This study will generate factual and comprehensive data that will contribute in improving response strategies to COVID-19 and the other possible emerging diseases with keen interest on the risk populations living with HIV and/or TB infected patients.
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