Immune Checkpoints Receptors Expression of Macrophage/Monocytes in Response to Acute Viral Respiratory Infection.

Background: We aimed to monitor the phenotypic changes in macrophages and their polarization in patients with acute viral respiratory diseases, including coronavirus disease diagnosis, focusing on the variations in the percentages of macrophages and monocytes and their sub-populations in those patients compared to healthy control. Moreover, we defined the correlation between macrophage subtypes and some inflammatory indices.

Methods: Twenty-seven patients with clinical and radiologic diagnosis of acute viral respiratory infection admitted in Al-Azhar and Assiut University hospitals were recruited. Fresh peripheral blood samples were collected from all patients and healthy controls for flow cytometric analysis using BD FACSCanto II analyzer equipped with three lasers.

Results: Compared to healthy controls, accumulation of cluster of differentiation (CD)11B⁺CD68⁺ macrophages (M) (P = 0.018), CD274⁺ M1 (P = 0.01), CD274⁺ M2 (P < 0.001), and CD80^-CD206⁺ M2 (P = 0.001) was more evident in patients. Moreover, CD273⁺ M2 (P = 0.03), CD80⁺CD206^- M1 (P = 0.002), and CD80⁺CD86⁺ M1 (P = 0.002) were highly expressed in controls compared with patients.

Conclusion: The examination of clinical specimens obtained from patients with signs of acute respiratory viral infection showed the role of the macrophage in the immune response. Dysfunction in macrophages results in heightened immune activity and inflammation, which plays a role in the progression of viral diseases and the emergence of accompanying health issues. This malfunction in macrophages is a common characteristic seen in various viruses, making it a promising focus for antiviral therapies with broad applicability. The immune checkpoint could be a target for immune modulation in patients with severe symptoms.