Adoptive Transfer of Regulatory T Cells Induced by Pregnancy May Mitigate the Severity of COVID-19 Infection in Pregnant Women

Severe coronavirus disease of 2019 (COVID-19) usually begins approximately one week after the onset of symptoms. Dyspnea is the most common symptom of severe disease and is often accompanied by hypoxemia. Progressive respiratory failure develops in many patients with severe COVID-19 after the onset of dyspnea and hypoxemia. These patients commonly meet the criteria for acute respiratory distress syndrome (ARDS), which is defined as the acute onset of bilateral infiltrates, severe hypoxemia, and lung edema. The majority of patients with severe COVID-19 showed some thromboembolic complications as well central or peripheral nervous system complications. Severe COVID-19 may also lead to acute cardiac, kidney, and liver injury, cardiac arrhythmias, coagulopathy, and shock. These organ failures may be associated with uncontrolled inflammation characterized by elevations in C-reactive protein and pro-inflammatory cytokines, including Interleukin-6, Interleukin-1, and tumor necrosis factor-α. This may associate with high fevers, thrombocytopenia, and exacerbating lung and cardiovascular complications. According to the American College of Obstetricians and Gynecologists (ACOG), the relative risk of COVID-19 infection is considerably lower relative to the risk of pandemic H1N1 (hemagglutinin type 1 and neuraminidase type 1) influenza infection in pregnant women. Less severe COVID-19 in pregnancy also was reported. Regulatory T cells (Tregs) are important in controlling adverse inflammatory reactions in severe COVID-19 making them effective cells for immunotherapy in severe COVID-19. Impairment in the number and/or function of Tregs was reported in severe COVID-19. Tregs are also part of the complex network of immune cells at the feto-maternal interface, and in peripheral blood that may have a critical role in facilitating implantation, placental development, and maintaining maternal tolerance. Pregnancy-induced Tregs are developed to control immune responses against paternal antigens. This review provides a new insight into whether the severity of COVID-19 could be influenced by the adoptive transfer of pregnancy-induced regulatory T cells in pregnant women. © 2023 The Author(s).