Placental pathology of the third trimester pregnant women from COVID-19.

AIMS: To explore the clinical characteristics and placental pathological changes of pregnant women with 2019 novel coronavirus (CoV) disease (COVID-19) in the third trimester, and to assess the possibility of vertical transmission. METHODS AND RESULTS: The placenta tissues were evaluated by using immunohistochemistry for inflammatory cells and Hofbauer cells, and using severe acute respiratory syndrome (SARS) CoV-2 RNA Fluorescence In-Situ Hybridization (FISH) and SARS-CoV-2 spike protein immunofluorescence (IF) double staining. All eight placentas from the third trimester pregnancy women were studied. All patients were cured, no clinical or serological evidence pointed to vertical transmission of SARS-CoV-2. Features of maternal vascular malperfusion (MVM) such as increased syncytial knots were present in all 8 cases (8/8), and increased focal perivillous fibrin depositions were presented in 7 cases (7/8). No significate chronic histiocytic intervillositis was noted in the placenta. The number of macrophages and inflammatory cells such as T cells, B cells and plasma cells in the placental villous was not significantly increased in all cases. Moreover, all of eight cases demonstrated negative results by FISH using a SARS-CoV-2 virus RNA probe and by IF using a monoclonal antibody against SARS-CoV-2 spike protein. CONCLUSIONS: We found no evidence of vertical transmission and adverse maternal-fetal outcomes in the placentas of third trimester COVID-19 pregnancy women, which provided further information for the clinical management of those women in the third trimester. However, further studies are still needed for patients with infections in different stage of gestation, especially in first and second trimester.

Pulmonary pathology of early-phase COVID-19 pneumonia in a patient with a benign lung lesion.

AIMS: An ongoing outbreak of 2019 novel coronavirus (CoV) disease (COVID-19), caused by severe acute respiratory syndrome (SARS) CoV-2, has been spreading in multiple countries. One of the reasons for the rapid spread is that the virus can be transmitted from infected individuals without symptoms. Revealing the pathological features of early-phase COVID-19 pneumonia is important for understanding of its pathogenesis. The aim of this study was to explore the pulmonary pathology of early-phase COVID-19 pneumonia in a patient with a benign lung lesion. METHODS AND RESULTS: We analysed the pathological changes in lung tissue from a 55-year-old female patient with early-phase SARS-CoV-2 infection. In this case, right lower lobectomy was performed for a benign pulmonary nodule. Detailed clinical, laboratory and radiological data were also examined. This patient was confirmed to have preoperative SARS-CoV-2 infection by the use of real-time reverse transcription polymerase chain reaction and RNA in-situ hybridisation on surgically removed lung tissues. Histologically, COVID-19 pneumonia was characterised by exudative inflammation. The closer to the visceral pleura, the more severe the exudation of monocytes and lymphocytes. Perivascular inflammatory infiltration, intra-alveolar multinucleated giant cells, pneumocyte hyperplasia and intracytoplasmic viral-like inclusion bodies were seen. However, fibrinous exudate and hyaline membrane formation, which were typical pulmonary features of SARS pneumonia, were not evident in this case. Immunohistochemical staining results showed an abnormal accumulation of CD4+ helper T lymphocytes and CD163+ M2 macrophages in the lung tissue. CONCLUSION: The results highlighted the pulmonary pathological changes of early-phase SARS-CoV-2 infection, and suggested a role of immune dysfunction in the pathogenesis of COVID-19 pneumonia.