Evaluation of lymphocyte subsets and NK cells in septic children.

BACKGROUND: Disorders of lymphocyte subpopulations counts and NK cells may not only contribute to impaired elimination of pathogens, but also be an important factor in the development of generalized inflammatory reaction. The aim of the paper was the analysis of subpopulations of lymphocytes and NK cells in children with sepsis and after recovery. MATERIAL/METHODS: The study comprised 25 septic children (17 infants and 8 children aged from 1 to 3 years). The control group consisted of 25 healthy children. The study was conducted in the initial phase of sepsis and then repeated 2 to 3 months after recovery. In all the children, the percentage and absolute numbers of basic lymphocyte subsets and NK cells in blood serum were evaluated. RESULTS: In the course of sepsis, the absolute number of activated lymphocytes T in the youngest children was higher in comparison with the control group. After recovery, the percentage and absolute counts of CD4 lymphocytes in all the children and CD3/CD4 lymphocytes ratio in the youngest children were considerably lower than in the control group. The percentage and absolute number of NK cells in the youngest children after recovery were higher in comparison with the control group. CONCLUSIONS: In children who underwent sepsis, depression traits of cellular immunity are observed. The occurrence of defensive system disorders after recovery may be an important factor in recurrent infections and creates the necessity of immune system monitoring in children with the history of sepsis for the purpose of prevention.