ABSTRACT
Objective: In COVID-19 disease, it was observed that T lymphocytes decreased numerically, both CD4+ and CD8+ could decrease, and sometimes the CD8+ level increased significantly. The virus-specific CD8+ T-cells are thought to be TEM or TEMRA cells. However, the characteristics of these cells, particularly their role in the pathogenesis of SARS-CoV-2 infection or COVID-19 disease, are unclear. Therefore, this study aimed to examine the flow cytometric changes observed in T helper, T cytotoxic cells, and subtypes during diagnosis in pediatric patients diagnosed with COVID-19 infection with SARS-CoV-2 PCR positivity. Methods: Twenty-two children aged 0-18, diagnosed with COVID-19, with flow cytometry;T Helper Cell (TH), T Cytotoxic Cell (TC), T Naive Cells (TN), Central Memory (TCM), Effector Memory (TEM), RA + Effector memory (TEMRA) and Recent Thymic Emigrants (RTEs) were studied. Results: T cell counts were found to be expected in all age groups. The CD4/CD8 ratio increased in the under-five and over 16 age group. While TCM among CD4+T cells decreased in the group above 16 years of age, TEM decreased in all age groups. RTEs decreased in all except the age group 16+. Naive CD8+ T cells (TN) were found to be high in all age groups. Conclusion: A low number of CD4+ and CD8+ lymphocytes have been reported as a distinctive laboratory finding in 2019 Coronavirus disease (COVID-19). Having enough naive T cells is essential for the immune system to respond consistently to unknown pathogens. This study found that these cells were higher than expected in children.
ABSTRACT
Objective: During viral infections, antibody production of B cells are critical for protective immunity. It is known that the COVID-19 disease has a milder course in children. It is crucial to evaluate the causes of this situation from a pediatrician's perspective to determine the treatment goals of the disease. We aimed to examine the flow cytometric changes in B cells and subtypes observed in children diagnosed with the COVID-19 infection. Materials and Methods: This is a prospective cohort study including 22 children aged 0-18 who had been diagnosed with COVID-19. CD19+B cells, CD27- IgD+ naive B, CD21low immature B, CD21lowCD38low active B, CD27- IgD- double-negative B, CD27- non-memory B, CD27+ memory B, CD27+IgD- switched memory B, and CD27+IgD+ non-switched memory B cells were studied using flow cytometry. Results: B cells counts decreased as a percentage in the 2-5 years age group and the 10-16 age group as an absolute number. Naive and non-memory B cell frequencies increased in the 5-10 years old and over 16 years old groups. Double negative B cells were normal in all age groups. Non-memory B cells increased in the 5-10 and over 16 years old groups, whereas memory B cells decreased. In all groups, switched memory B cells decreased. Non-switched memory B cell counts were within reference ranges in all groups except for the over 16 years group. Conclusion: Although the decrease in B cell count is associated with the severity of the disease, naive B cell subgroups did not decrease in the pediatric patients included in the study. All groups showed increased switched memory B cell counts, in accordance with the literature. Unlike adults, naive B cells, non-switched memory B cells, and double-negative B cells were normal in children.
ABSTRACT
Objective: During viral infections, antibody production of B cells are critical for protective immunity. It is known that the COVID-19 disease has a milder course in children. It is crucial to evaluate the causes of this situation from a pediatrician's perspective to determine the treatment goals of the disease. We aimed to examine the flow cytometric changes in B cells and subtypes observed in children diagnosed with the COVID-19 infection. Materials and Methods: This is a prospective cohort study including 22 children aged 0-18 who had been diagnosed with COVID-19. CD19(+)B cells, CD27(-)IgD(+) naive B, CD21(low )immature B, CD21(low)CD38(low) active B, CD27(-)IgD(-) double-negative B, CD27(-) non-memory B, CD27(+) memory B, CD27(+)IgD(-) switched memory B, and CD27(+)IgD(+) non-switched memory B cells were studied using flow cytometry. Results: B cells counts decreased as a percentage in the 2-5 years age group and the 10-16 age group as an absolute number. Naive and non-memory B cell frequencies increased in the 5-10 years old and over 16 years old groups. Double negative B cells were normal in all age groups. Non-memory B cells increased in the 5-10 and over 16 years old groups, whereas memory B cells decreased. In all groups, switched memory B cells decreased. Non-switched memory B cell counts were within reference ranges in all groups except for the over 16 years group. Conclusion: Although the decrease in B cell count is associated with the severity of the disease, naive B cell subgroups did not decrease in the pediatric patients included in the study. All groups showed increased switched memory B cell counts, in accordance with the literature. Unlike adults, naive B cells, non-switched memory B cells, and double-negative B cells were normal in children.
ABSTRACT
Introduction: SARS-CoV-2 binds to angiotension coverting enzyme-2 (ACE-2) receptors on the surface of the the host cells. ACE receptors are found in bone marrow (BM). SARS-CoV-2 can reduce hematopoiesis in all cell lines by infecting the BM cells directly and by changing the local RAS in addition to the suppression by cytokines during the course of COVID-19. However, there has been no study that could demonstrate the presence of SARS-CoV-2 in BM. Therefore in this study, we aim to demonstrate SARS-CoV-2 in the BM and investigate the changes in the BM of critically ill COVID-19 patients. Materials and method: This study is single center research and six critically ill COVID-19 patients were included in the study. Flowcytometry and RT-PCR were studied in BM aspiration samples. Histopathological evaluation of bone marrow biopsy materials was performed. Results: The most striking finding in BM was reactive plasmacytosis. CD4 / CD8 ratio of 3 patients was reversed (<1). There was an average of 90% CD14+ CD16- classical monocyte. In 1 patient SARS-CoV-2 was demonstrated in BM cells by RT-PCR. Conclusion: To the best of our knowledge, this is the first study which demonstrated SARS-CoV-2 in the BM. In our study revealed an increase in polyclonal plasma cells, CD14+ CD64+ CD68+ active monocytes in BM and demonstrated SARS-CoV-2 in the BM by RT-PCR analysis in 1 patient. Evaluation of flowcytometric analysis of the BM in COVID-19 patients may help the scientists to understand the pathogenesis of SARS-CoV-2 and its effects on hematopoietic cells. © 2021 A. CARBONE Editore. All rights reserved.