Objective: To investigate the influencing factors for lymphocyte subsets in children 0 to 6 years of age.
Methods: Umbilical artery blood samples from 45 healthy full-term infants and venous blood samples from 79 healthy children between 0 and 6 years were collected. According to the methods of delivery, the full-term infants were divided into vaginal delivery group (n=22) and cesarean section group (n=23). Healthy children were divided into different age groups: 28 days to 12 months (n=25), 1-3 years (n=26), and 3-6 years (n=28). Lymphocyte subsets were examined by flow cytometry. The influencing factors including delivery method, sex, and age, which might have an effect on the lymphocyte subsets, were analyzed.
Results: There were significant differences in T and Ts cell counts, percentage of B cells, and percentage and count of natural killer (NK) cells between the full-term infants of vaginal delivery and cesarean section (P<0.05). The absolute counts and percentages of different lymphocyte subsets showed no significant differences between males and females in healthy children (P>0.05). The counts of all lymphocyte subsets except Ts and NK cells varied significantly between different age groups (P<0.05).
Conclusions: Lymphocyte subsets in children under 6 years of age are more profoundly affected by age. Delivery method is also a contributing factor in newborn infants. The reference range of lymphocyte subsets in children should be established for different age groups.