Increased Activation Markers of Adaptive Immunity in Patients with Severe COVID-19.

COVID-19 is a pandemic disease and is widespread over the world. This disease shows a 5.1% mortality. The understanding of the disease has expanded rapidly in many areas, including virological, epidemiological, clinical, and management dimensions. To better understand the inflammatory and immune profiles that impact the pathogenesis and development of severe COVID-19 symptoms, further studies are essential. This research aims to explore the inflammatory and adaptive immune responses associated with COVID-19, considering factors such as genetic diversity and environmental exposure among Saudi patients. The goal is to determine if patients with severe COVID-19 exhibit different disease phenotypes. This case-control study includes 115 participants (healthy and with COVID-19 infection), 55 of which had confirmed cases of COVID-19 in intensive care units (ICUs) at different hospitals in Makkah City, Saudi Arabia. Whole blood samples were collected from June to September 2021 for cellular analyses, and inflammation marker data were collected from hospital records. The expression of activation markers on B (CD27 and CD38) and T cells (CD27 and HLA-DR) was obtained using the flow cytometry technique. Also, serum was collected for cytokine measurements, including IL-6, INF-γ, and TNF- α. The results indicated that lymphopenia and excessive T cell activation were more prevalent in severe cases than in healthy individuals. Furthermore, the results revealed that severe COVID-19 patients had an increased frequency of CD19+ B cells, with changes in B cell subsets. The current study implies impairment and changes in the phenotype of adaptive cells (including T and B cells), with an increase in HLA-DR molecules and inflammation markers with pro-inflammatory cytokines in severe COVID-19 cases. The current study implies impairment and changes in the phenotype of adaptive cells (including T and B cells), with an increase in HLA-DR molecules and inflammation markers in severe COVID-19 cases, which could be targeted for therapeutic interventions. This might be a valuable approach for the diagnosis and treatment of severe COVID-19 cases.