Infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which is the causal agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic, has claimed more than 6.8 million lives worldwide. It remains imperative to understand the immune responses to SARS-CoV-2, particularly in high-risk groups, to formulate better vaccination and treatment strategies.
Study
A recent study analyses the adaptive, innate, and humoral immune responses to SARS-CoV-2 using samples from 119 women.
Blood samples were collected from 23 pregnant women with polymerase chain reaction (PCR)-confirmed COVID-19, 12 of whom developed an acute infection and 14 recovered from infection. Similarly, blood samples of 33 non-pregnant women with COVID-19 were collected, 12 of whom were acutely infected and 14 were convalescent. For the control group, blood samples from 21 healthy pregnant and 42 non-pregnant women who did not have a history of COVID-19 were obtained.
This study qualified 217 immunological parameters and analyzed blood samples from one to 258 days after disease onset. This long-term analysis provides a comprehensive map of immune responses during acute and convalescent phases of SARS-CoV-2 infection in pregnant women.
Results
Comparable antibody characteristics were observed between pregnant and non-pregnant women with COVID-19. Additionally, SARS-CoV-2 receptor binding domain (RBD) and N-specific immunoglobulin G (IgG) antibodies were detected in the cord blood of convalescent pregnancies.
Consistent with previous studies, the presence of SARS-CoV-2-specific antibodies in pregnant women was observed post-infection.
Cellular immunity in pregnant and nonpregnant women with SARS-CoV-2 infection was also compared, which demonstrated typical activation patterns of classical αβ CD4+ and CD8+ T-cells. NK and γδ T-cell activation was similar during acute infection, which indicates that both groups induce similar innate responses after SARS-CoV-2 infection.
Women undergoing a healthy pregnancy have a higher abundance of activated NK and γδ T-cells, which could have prevented the development of acute SARS-CoV-2 infection. Lower levels of circulating MAIT cells were also found in healthy pregnant women, which remained consistent, even during the acute infection phase.
In the second and third trimesters of a healthy pregnancy, higher frequencies of a CD56+ γδ T-cell subset were observed as compared with nonpregnant women. Higher levels of human leukocyte antigen (HLA)-DR-expressing γδ T-cells were observed, thus indicating the role of activated γδ T-cells during a normal pregnancy.
An increased frequency of interleukin 8 (IL-8), IL-10, and IL-18 were observed in healthy pregnant women, which remained elevated during SARS-CoV-2 infection. Pregnant and non-pregnant women with SARS-CoV-2 infection shared similar chemokine and cytokine profiles, except GRO-a and eotaxin.
Consistent with previous studies, the current study revealed a Th2 cytokine response in pregnant women, with a few differences in its level between pregnant and non-pregnant women with acute COVID-19. Immune cell analysis of the placenta of women with a healthy pregnancy and those with COVID-19 revealed comparable levels of NK and T-cell activation.
Conclusion
Similar levels of antibody production and adaptive cellular responses were observed between unvaccinated pregnant and non-pregnant women with acute or convalescent SARS-CoV-2 infection. Nevertheless, the NK and γδ T-cell activation, as well as inflammation, were altered during pregnancy.
Taken together, the findings of this study provide important insights into the immune responses during pregnancy, which can help formulate better treatment strategies for pregnant women with COVID-19.
Source:
https://www.news-medical.net/news/20230416/Pregnant-women-show-unique-immune-response-to-COVID-19.aspx