Effects of Coronavirus Disease 2019 (COVID-19) on Peripheral Blood Lymphocytes and Their Subsets in Children: Imbalanced CD4 + /CD8 + T Cell Ratio and Disease Severity

• Published in: Frontiers in pediatrics Vol. 9; p. 643299
• Main Authors: Mahmoudi, Shima, Yaghmaei, Bahareh, Sharifzadeh Ekbatani, Meisam, Pourakbari, Babak, Navaeian, Amene, Parvaneh, Nima, Haghi Ashtiani, Mohammad Taghi, Mamishi, Setareh
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 14-04-2021
• Subjects: CD4+/CD8+ lymphocytes; children; COVID-19; lymphocyte; Pediatrics; SARS-CoV-2; COVID-19; CD4+/CD8+ lymphocytes; SARS-CoV-2; children; lymphocyte
• ISSN: 2296-2360; 2296-2360
• DOI: 10.3389/fped.2021.643299

While pathogenesis in COVID-19 is not fully known and the effects between SARS-CoV-2 and the immune system are complicated, it is known that lymphopenia, hyper-inflammatory responses, and cytokines play an important role in the pathology of COVID-19. While some hematological abnormalities have been described among the laboratory features of COVID-19, there have not been studies reported on lymphocyte subset analyses in children. The aim of this study was to describe lymphocyte subsets in pediatric patients with mild/moderate or severe COVID-19.
The subjects in the study were children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia confirmed with the real-time RT-PCR. The subjects were admitted to the Children's Medical Center, affiliated with the Tehran University of Medical Sciences, between March 7
and June 10
of 2020. The complete blood counts and lymphocyte subpopulations were analyzed for each patient.
The study included 55 hospitalized patients with confirmed SARS-CoV-2 infection (34 patients (62%) with an observed mild/moderate case of the disease and 21 patients (38%) with severedisease). Lymphocyte counts were found to be lower in patients with a severe case (mean ± SD 1.6 ± 0.9 in the severe group vs. 2.3 ± 2.2 in the mild group). Compared to the group with mild/moderate pneumonia, children with severe pneumonia had an increased count of CD8
T cell and a lower percentage of CD4
T cell. However, the differences between the groups were negligible. Interestingly, the severe group had a lower CD4
/CD8
T cell ratio compared to the mild group (1.1 ± 0.47 vs. 1.4 ± 0.8,
-value: 0.063). CD4
/CD8
T cell ratio <2, 1.5, and 1 was found in 48 (87%), 40 (73%), and 19 cases (35%). All of the seven cases in which the subject passed (13%) had CD4
/CD8
T cell ratio of <2, 86% had CD4
/CD8
T cell ratio of <1.5, and 29% had CD4
/CD8
T cell ratio of <1.
The CD4
/CD8
T cell ratio was lower in patients with severe COVID-19 compared to those with mild/moderate form of disease. However, although a decline in CD4
/CD8
ratio may serve as a useful metric in analyzing of the derangement in immune responses in patients with severe COVID-19, further study with larger sample sizes is highly recommended.