Lymphocyte Subsets in Mild COVID-19 Pediatric Patients

Objective: The reasons for a high prevalence of asymptomatic or mild coronavirus disease (COVID-19) and rare severe disease in children have been explained by non-immune and immune mechanisms. This study aimed to evaluate the immune system’s response to severe acute respiratory syndrome coronavirus 2 by investigating lymphocyte subsets.

Materials and Methods: This study included 33 coronavirus disease positive children, of whom 12 had mild disease and 21 had an asymptomatic infection as the patient group and 26 age- and gender-matched healthy children as the control group. The demographic information, symptoms, physical examination findings, complete blood count, C-reactive protein (CRP), procalcitonin, and lymphocyte subsets were recorded in all subjects.

Results: Leukocyte, lymphocyte, monocyte count, and hemoglobin levels of our pediatric coronavirus disease patients were similar to the control group. Neutrophil was lower in the coronavirus disease cases compared to the control group. CRP and procalcitonin levels of asymptomatic cases were similar to the control group. B cell count, CD8+ T cell count, and CD4/CD8 ratio (dividing the CD4 cell count by the CD8 cell count) ratio were similar in the patient and control groups. Natural killer, T cell, and CD4+ T cell counts were significantly higher in the whole patient group compared to the control group.

Conclusion: One reason for mild severe acute respiratory syndrome coronavirus 2 infection in children may be an increase in some lymphocyte subsets such as natural killer cells, T cell, and CD4+ T cell. Understanding the answer to the question of why children develop more protective immunity to the virus could be an essential step for developing new treatments.

The newborn conjunctival flora at the post delivery 24 hours

Purpose

The aim of this study was to investigate the aerobic conjunctival flora of neonates and the effects of delivery type on conjunctival flora development in neonates who were born with normal spontaneous vaginal delivery (SVD) or elective caesarean section (C/S) and who were not given prophylactic antibiotic eye drops after birth.

Methods

This cross-sectional study included 95 healthy newborns. One day after the delivery, conjunctival samples were taken from newborns who were born with normal SVD or elective C/S, and not given prophylactic antibiotic eye drops after birth. Newborns with conjunctival hyperemia and discharge were excluded from study. Samples were plated in blood agar, EMB, and chocolate agar. These cultures were incubated at 37 °C for 24-48 h. Antibiotic sensitivity was evaluated using Kirby-Bauer disc diffusion method.

Results

Staphylococcus aureus (S.aureus) growth was observed in 7 (70%) and coagulase negative staphylococcus (CNS) growth in 2 (20%) out of 10 eyes with bacterial growth in 9 culture positive newborns born with C/S. Two S.aureus strains were resistant to methicillin. On the other hand, CNS growth was observed in the conjunctival cultures of 17 out of 19 eyes with bacterial growth in 16 culture positive newborns born with SVD. In 2 eyes with CNS growth, there was also S.aureus growth. The positive cultures for S.aureus were significantly higher in the conjunctival cultures of neonates born with C/S compared to neonates born with SVD, where CNS growth was significantly lower (P = 0.002). All isolates were susceptible to vancomycin, teicoplanin, and gatifloxacin. Two isolates were resistant to methicillin.

Conclusions

In deliveries with C/S, the newborn does not contact the vagina. This may result in changes of bacterial characteristic of the flora. Culture positivity for S.aureus was higher in C/S compared to SVD, which may be important in case neonatal conjunctivitis develops.