Circulatory EVs as a predictor of chronic urticarial activity.

Background: Chronic urticaria (CU) is a common and complex disorder that occurs without any identifiable provoking factor. The mechanisms underlying CU pathogenesis are still not fully understood. The autoimmune theory of IgG autoantibodies to IgE/high-affinity receptor of IgE on mast cells and mast cell activation and autoallergy (IgE-mediated disease) might contribute to CU pathogenesis. Extracellular vesicles (EVs) are membranous vesicles released from apoptotic or activated cells of different types. In this study, we aimed to investigate circulating EVs as potential biomarkers in patients with CU compared with that in healthy controls. Methods: We studied 15 patients with CU and 16 healthy controls. Circulatory EVs (plasma) were characterized by the presence of externalized phosphatidylserine (annexin V staining). An unpaired t-test was used, and P < 0.05 was considered statistically significant. Results: We did not find significant differences in the total number of EVs in patients with CU. A significant decrease in the levels of T-cells (CD3) and endothelial cells (CD146) (P < 0.05) in these patients than in controls was found. No significant differences were observed between patients with CU and healthy controls in terms of platelets, macrophages, PECAM-1, B cells, and tissue factors. Conclusion: Endothelial cells have been shown to contribute to the pathogenesis of CU and are also targeted by mediators released by mast cells and other cellular infiltrates. We identified that circulatory endothelial and T-cell EVs might play an important role in CU pathogenesis. In addition, our study highlights the importance of EVs as future therapeutic targets to be investigated.

Aerobiological monitoring in a desert type ecosystem: Two sampling stations of two cities (2017-2020) in Qatar.

BACKGROUND: The increasing number of aerobiological stations empower comparative studies to determine the relationship between pollen concentrations in different localities and the appropriate distance, which should be established between sampling stations. In Qatar, this is basically the first aerobiological study for a continuous monitoring interval. OBJECTIVES: The study aimed to assess the abundance and seasonality of the most prevalent pollen types, plus identify potential differences between two sites within the country. METHODS: Airborne pollen data were collected during 2017-2020 by using Hirst-type volumetric samplers in Doha capital city and Al Khor city in Qatar, placed 50 km apart. RESULTS: Higher total pollen indexes were recorded in the Al Khor station (2931 pollen * day/m3) compared to the Doha station (1618 pollen * day/m3). Comparing the pollen spectrum between the sampling stations revealed that ten pollen types were found in common. Amaranthaceae and Poaceae airborne pollen constituted 73.5% and 70.9% of the total amount of pollen detected at the samplers of Al Khor station and Doha station. In both sampling sites, a very pronounced seasonality was shown; August-October appeared as the period with the most intense incidence of atmospheric herbaceous pollen, with 71% and 51% of the annual total counts in Al Khor and Doha stations, respectively. August (Al Khor, 21%; Doha, 9%), September (Al Khor, 33%; Doha, 26%), October (Al Khor, 17%; Doha, 16%) were the months in which the herbs pollen concentrations were highest. Significant statistical differences between the two stations were observed in specific pollen types with local distribution in each trap's vicinity. CONCLUSIONS: Comparison of data obtained by the two samplers running at a distance of 50 Km indicated that potential inter-site differences could be attributed to the vegetation surrounding the city having a decisive influence on data collected.

The correlation between middle schoolchildren allergic symptoms and airborne particle season: A cross-sectional study.

ABSTRACT: Limited studies correlate allergic symptoms and associated outdoor biological particle exposure among schoolchildren globally.This study aimed to investigate the relationship between the seasonality of symptoms of allergic diseases among middle schoolchildren and the annual variation of airborne pollen and fungal spore in a hot and humid geographical region (Qatar).During November 2017 to January 2018, a self-reported study of middle schoolchildren living in the Doha capital city of Qatar was conducted, and data gathered were evaluated in relation to the collected monthly pollen and fungal spores. Participants' data were collected by conducting a survey based on a modified questionnaire adopted from the International Study of Asthma and Allergy in Childhood (ISAAC). The airborne pollen and fungal spore in Doha's atmosphere were extracted from the Doha aerobiology project (2017-2020).Among the 1000 distributed questionnaires, 100 were excluded due to significant missing data and 644 middle schoolchildren living in Doha city responded and were included in the final analysis. The symptoms of allergic rhinitis (AR) pattern among the responders with positive symptoms were strongly linked with the higher airborne fungal spore incidence during the month of November. Out of 331 students with positive symptoms, the prevalence of AR, lifetime wheeze, and eczema was 62.8%, 28.1%, and 26.6%, respectively. Asthma was significantly higher in Qatari (39.8%) compared to non-Qatari (26.7%) middle schoolchildren (P = .02).Outdoor aeroallergen may be a contributing factor in addition to other environmental and genetic predisposing factors for childhood atopic diseases in the prevalence rate of allergic symptoms among middle schoolchildren in the peninsula of Qatar.

The association between airborne pollen monitoring and sensitization in the hot desert climate.

BACKGROUND: Pollen is a major cause of allergic respiratory diseases. In Qatar, data on the presence and prevalence of allergenic airborne types of pollen is quite limited. METHODS: The study aimed to determine and correlate the most frequently implicated airborne pollen detected by aerobiological monitoring samplers in respiratory allergy symptoms. An aerobiological survey was started on May 8, 2017. Airborne pollen was collected using two Hirst type seven-day recorder volumetric traps. Skin prick test in patients attending allergy clinics in Doha using commercial extracts was conducted. RESULTS: Twenty-five pollen types representing the native, as well as the introduced plants, with a relatively low daily mean concentration were observed from May 2017 to May 2019. The highest pollen concentrations were reached by Amaranthaceae (58.9%), followed by Poaceae (21.7%). SPT revealed a comparatively higher degree of sensitization to pollen. Among 940 patients, 204 were sensitized to pollen (54% female) with 135 (66.2%) and 114 (55.8%) to Amaranthaceae and Poaceae, respectively. Some patients had polysensitization. There was a statistically significant association between Amaranthaceae, and asthma (r = 0.169, P = 0.016) and allergic rhinitis (r = 0.177, P = 0.012). CONCLUSIONS: This is the first study to monitor airborne pollen in the state of Qatar. The main pollen detected were Amaranthaceae and Poaceae. Pollen may represent a possible exacerbating factor in adult patients with allergic diseases such as asthma and allergic rhinitis.