Time to SARS-CoV-2 clearance in African, Caucasian, and Asian ethnic groups.

BACKGROUND: COVID-19 may become a seasonal disease. SARS-CoV-2 active circulation coupled with vaccination efforts has undoubtedly modified the virus dynamic. It is therefore important investigate SARS-CoV-2 dynamic in different groups of population following the course of spatiotemporal variance and immunization. METHODS: To investigate SARS-CoV-2 clearance in different ethnic groups and the impact of immunization, we recruited 777 SARS-CoV-2-positive patients (570 Africans, 156 Caucasians, and 51 Asians). Participants were followed and regularly tested for 2 months until they had two negative tests. RESULTS: The vaccination rate was 64.6%. African individuals were less symptomatic (2%), Caucasians (41%) and Asians (36.6%). On average, viral clearance occurred after 10.5 days. Viral load at diagnosis was inversely correlated with viral clearance (p < 0.0001). The time of SARS-CoV-2 clearance was higher in Africans and Caucasians than in Asians (Dunn's test p < 0.0001 and p < 0.05, respectively). On average, viral clearance occurred within 9.5 days during the second semester (higher rate of vaccination and SARS-CoV-2 exposition), whereas it took 13.6 days during the first semester (lower rate of vaccination and SARS-CoV-2 exposition) (Mann-Whitney t-test p < 0.0001). CONCLUSION: In conclusion, ethnicity and spatiotemporal changes including SARS-CoV-2 exposition and immunization affect SARS-CoV-2 clearance.

Prostate malignant tumor and benign prostatic hyperplasia microenvironments in black African men: Limited infiltration of CD8+ T lymphocytes, NK-cells, and high frequency of CD73+ stromal cells.

BACKGROUND: Anti-cancerous immunology has yet to be investigated in the African black population, despite being the dawn of precision medicine. AIM: Here we investigated the tumor microenvironment of prostate cancer and benign prostatic hyperplasia (BPH) in black Africans. METHODS: Through immunohistochemistry analysis of prostate cancer and BPH patients' biopsies, we investigated the expression and distribution of CD73, CCD8 T-lymphocytes, and natural killer cells. In addition, we looked at tumor-infiltrating features CD8 T-lymphocytes and natural killer cells. RESULTS: We show for the first time in black Africans a high expression of CD73 in epithelial-stromal cells and virtually no infiltration of CD8 T lymphocytes and natural killer cells in the tumoral area. In addition, CD73 was seven (7) times more likely to be expressed in prostate cancer stromal tissues than in benign prostatic hyperplasia tissues (odds ratio = 7.2; χ2 = 21; p < .0001). In addition, PSA concentration was significantly higher in prostate cancer patients than in BPH patients (p < .001). Also, the PSA-based ROC. analysis showed an area under the curve of 0.87 (p < .0001). CONCLUSION: CD73 expression is more likely expressed in prostate cancer stromal tissues than in benign prostatic hyperplasia tissues. The features of prostate cancer in Black Africans suggest CD73 expression as a possible target for immunotherapy in this population.

Allergen sensitization and polysensitization pattern of adults and children in an urban Sub-Saharan African setting (Libreville, Gabon).

Background: It is believed that allergic diseases are increasing in Africa. However, the health sector in Africa has yet to catch up with this paradigm shift. We looked at the number of patients referred to us for allergy testing and investigated allergen sensitization. Methods: A retrospective analysis was done on 97 serum allergen-specific IgE results collected from patients suspected of having allergies in Libreville from 2018 to 2021. Specific IgE responses to 180 allergens were investigated. The general sensitization patterns were analyzed. Also analyzed were sensitization patterns for adults and children. The difference in the IgE-binding allergen positivity rate between groups was calculated by using the chi-square (χ2) test. Results: The allergens most commonly causing sensitization were from mites (65%), barley (48%), peach (48%), dog and/or cat dander (44%), house dust (44%), peanut (39%), tomato (39%), cockroach (37%), crab (36%), garlic and/or onion (34%), rye (34%), egg white (32%), shrimp (32%), kiwi (32%), soya bean (32%), citrus mix (29%), cheese (27%), milk (27%), walnut (27%), ox-eye daisy (24%) and orchard grass (24%). Moreover, 60% of patients (36 of 60) were polysensitized to inhalant allergens, 53% (31 of 58) were polysensitized to food allergens, and 29% (14 of 48) were polysensitized to inhalant and food allergens; 65% of patients (53 of 81) were sensitized to allergens originating from mites, fungi (including Candida albicans, Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum, and Pennicillium notatum), or bacteria (staphylococcal enterotoxin B). Conclusions: The sensitization pattern of allergens in our setting is rich and varied, with a high prevalence of polysensitization.