Clinical manifestations of SARS-CoV-2 infection range from mild to critically severe. The aim of the study was to highlight the immunological events associated with the severity of SARS-CoV-2 infection, with an emphasis on cells of innate immunity. Thirty COVID-19 patients with mild/moderate symptoms and 27 patients with severe/critically severe symptoms were recruited from the Clinical Center of Kragujevac during April 2020. Flow cytometric analysis was performed to reveal phenotypic and functional alterations of peripheral blood cells and to correlate them with the severity of the disease. In severe cases, the number of T and B lymphocytes, dendritic cells, NK cells, and HLA-DR-expressing cells was drastically decreased. In the monocyte population proportion between certain subsets was disturbed and cells coexpressing markers of M1 and M2 monocytes were found in intermediate and non-classical subsets. In mild cases decline in lymphocyte number was less pronounced and innate immunity was preserved as indicated by an increased number of myeloid and activated dendritic cells, NK cells that expressed activation marker at the same level as in control and by low expression of M2 marker in monocyte population. In patients with severe disease, both innate and adoptive immunity are devastated, while in patients with mild symptoms decline in lymphocyte number is lesser, and the innate immunity is preserved.

Introduction/Objective Bacterial vaginosis (BV) is defined as disequilibrium of vaginal microbiota due to proliferation of Gram-negative/variable anaerobes and reduction/depletion of vaginal lactobacilli. Difficulties in interpreting microscopically categorized findings in diagnosis of BV need a molecular analysis of bacteria present in vaginal discharge of patients. In this regard, we performed real-time qPCR analysis of vaginal discharge samples with the goal to explore in which extent prevalence and amount of anaerobes, Gardnerella vaginalis and Atopobium vaginae, are related to findings obtained by microscopy. Methods This study enrolled 111 asymptomatic pregnant women between 24 and 28 weeks of pregnancy. Gram-stained vaginal smears were evaluated microscopically. Afterwards, DNA of bacteria was extracted from Gram slides and real-time qPCR was performed with the aim to detect and quantify G. vaginalis and A. vaginae. Results The data of our study showed that 53.2% of patients had normal results, while 20.7% and 26.1% of patients had intermediary (IMD) and BV results, respectively. G. vaginalis and A. vaginae were more frequently found in IMD and BV than in healthy patients; also, the average bacterial number of G. vaginalis and A. vaginae were significantly higher in BV and IMD than in the group with normal findings (p = 0.000). Comparing mutual relation of G. vaginalis and A. vaginae, the prevalence and number of G. vaginalis were in all groups significantly higher than A. vaginae. Conclusion The data of our study have shown that in distinguishing normal from BV findings, quantification of bacteria may be more important than just molecular detection of bacteria.

Clinical manifestations of SARS-CoV-2 infection range from mild to critically severe. The aim of the study was to highlight the immunological events associated with the severity of SARS-CoV-2 infection, with an emphasis on cells of innate immunity. Thirty COVID-19 patients with mild/moderate symptoms and 27 patients with severe/critically severe symptoms were recruited from the Clinical Center of Kragujevac during April 2020. Flow cytometric analysis was performed to reveal phenotypic and functional alterations of peripheral blood cells and to correlate them with the severity of the disease. In severe cases, the number of T and B lymphocytes, dendritic cells, NK cells, and HLA-DR-expressing cells was drastically decreased. In the monocyte population proportion between certain subsets was disturbed and cells coexpressing markers of M1 and M2 monocytes were found in intermediate and non-classical subsets. In mild cases decline in lymphocyte number was less pronounced and innate immunity was preserved as indicated by an increased number of myeloid and activated dendritic cells, NK cells that expressed activation marker at the same level as in control and by low expression of M2 marker in monocyte population. In patients with severe disease, both innate and adoptive immunity are devastated, while in patients with mild symptoms decline in lymphocyte number is lesser, and the innate immunity is preserved.