Introduction: 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. Methods: 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 th and June 10 th of 2020. The complete blood counts and lymphocyte subpopulations were analyzed for each patient. Results: 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, p -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. Conclusion: 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.
【저자키워드】 COVID-19, SARS-CoV-2, children, lymphocyte, CD4+/CD8+ lymphocytes, 【초록키워드】 pathology, coronavirus, immune response, Pathogenesis, severe COVID-19, Pneumonia, SARS-COV-2 infection, cytokine, immune system, CD4, CD8, lymphopenia, T cell, Lymphocyte subset, complete blood count, Patient, Mild, severe pneumonia, real-time RT-PCR, group, university, disease, Analysis, acute respiratory syndrome, Pediatric patient, Sample size, Medical Sciences, subject, severe group, center, Severe case, hematological, Hyper-inflammatory responses, abnormality, Tehran, while, Effect, Seven, described, analyzed, reported, the disease, hospitalized patient, subset, laboratory feature, lymphocyte subpopulation, 【제목키워드】 CD4, Effect, peripheral, Ratio,