Comparative analysis of TREC and KREC concentration levels in children at medical and biological risk (CHD – frequently ill children, children who have been operated for congenital heart defect with combined thymectomy, children – without it) and tho

The purpose of the study was to compare and analyze the levels of KREC (kappa-deleting recombination excision circle) and TREC (T cell receptor excision circle) levels, which indirectly reflect impaired maturation of T and/or B lymphocytes, in children of the medical and biological risk group and the comparison group (patients considered relatively healthy, relative to the population). The medical and biological risk groups were: 1) 15 children with operated congenital heart defects with combined thymectomy and 9 without it; the average age is 5 months ±4 months and 7 months ±3 months, respectively; and 2) 27 children with relatively frequent morbidity of the respiratory tract (acute respiratory viral infection more than 8 times a year) aged 1.6±1.4 months, among whom the proportion attending a preschool institution is 20 people (74%). The comparison groups were: 1) 16 relatively healthy children (health group 1) aged 1.7±1.6 years, among whom the proportion of those attending a preschool institution was 13 people (81%); and 2) 48 apparently healthy newborn children, whose average age was 15±12 days. Quantitative determination of TREC and KREC was carried out using a multiplex test system developed at the Institute of Chemical Biology and Fundamental Medicine of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk). The average concentrations of TREC and KREC were determined in apparently healthy newborns. Children with a high incidence of infectious respiratory morbidity (more than 8 cases of acute respiratory viral infection per year) had a significantly higher risk of developing disorders of both T cell and B cell immunity, compared with the healthy population. Children who underwent total thymectomy during surgical treatment of congenital heart defects had a higher risk of developing immunodeficiency conditions, affecting predominantly T cell immunity, in comparison with the group of children operated on with preservation of the thymus gland.