Comparação da resposta imunológica periférica e achados histopatológicos placentários de gestantes e puérperas infectadas ou não por Sars-CoV2

Abstract

The immune response of pregnant women with COVID-19, as well as the histopathological changes in the placenta caused by the infection, have not yet been elucidated. The characterization of lymphocyte subpopulations and natural killer (NK) cells, via flow cytometry, in the peripheral blood of pregnant and postpartum women infected or not by SARS-CoV-2, together with placental histopathological analysis, can contribute with more evidence on the effects caused by COVID-19 during the puerperal pregnancy period. In this cross-sectional study, the peripheral levels of total T lymphocytes, TCD4+ lymphocytes (ThL), TCD8+ lymphocytes (TcL), B lymphocytes and NK cells, in pregnant and postpartum women with positive and negative PCR for SARS-CoV-2 were compared. In addition, a comparison of placental histopathological findings was performed, using the Hematoxylin/Eosin staining method, of part of the parturients included in the study. The collection of peripheral blood and placental tissue samples took place between May 2021 and March 2022, in a teaching hospital in the northeast region of Brazil. Immunophenotyping was performed in 99 women, of which 78 (78.8%) had a confirmed diagnosis of COVID-19. Pregnant women and postpartum women infected with SARS-CoV-2 had higher levels of cytotoxic T cells, median (ME) = 574.2; interquartile range (IIQ) = 382.4, when compared with uninfected patients, ME = 404.7; IIQ = 363.5); p = 0.032. Pregnant women with COVID-19 had a lower mean CD3+ count (1,351.1 ± 337.7) compared to postpartum women with the disease (1,605.6 ± 538.6); t (53.6) = -2.45, p = 0.009. Likewise, lower CD16+/56+ (113.3; IIQ = 172.0) and CD3+/CD16-56+ (52.1; IQ = 53.4) medians were found in pregnant women with COVID-19, when compared with the group of postpartum women without COVID19 (191.2; IIQ = 192.5); U = 396.0, p = 0.043 and (70.8; IIQ = 91.6); U = 376.5, p = 0.025, respectively. Histopathological analysis was performed on 30 placentas, of which 10 parturients had a diagnosis of COVID-19 confirmed by PCR (33.3%). Results revealed higher levels of congestion, focal chronic villitis, and acute funisitis in placentas from COVID-19 positive parturients. Negative parturients had a higher percentage of intervillous hemorrhage with thrombus formation, dystrophic calcification, placental infarction except marginal and acute capsular deciduitis. However, there was no statistically significant difference between the groups, nor a predominant histopathological pattern in pregnant women infected by the virus in the sample studied for comparison of placental findings. Pregnant women and postpartum women with COVID-19 had significantly higher levels of cytotoxic T cells in peripheral blood, but there was no difference in placental histopathological findings, although the group with confirmed infection had a higher percentage of congestion, focal chronic vilitis and acute funisitis.