The Role of Immune Markers in Predicting Infectious Complications in Children with Congenital Heart Defects

The literature review presents data from a limited number of available studies conducted over the last two decades on immunological deficiency in congenital heart defects (CHDs), which is the cause of frequent infectious complications before and after cardiac surgery. Several studies based on screenings at various levels indicate the presence of primary and secondary immunodeficiency in CHDs, in particular about 13 genetic syndromes in which CHD is combined with immunodeficiency. The available data suggests a greater severity of immunological disorders in patients with critical CHDs, cyanotic CHDs, and conotruncal defects with T-cell dysfunction and deficiency of immunoglobulins (especially the IgG class, mainly IgG4) than in patients with shunts and obstructive defects. To identify defects in the T- and B-cell components of the immune system, quantification of the DNA of T-cell receptor excision circles (TRECs) and K-deleting recombination excision circles (KRECs)-by-products of the maturation of T- and B-cell receptors- has proven helpful in the world practice of neonatal screening. It allows the evaluation of a number of functionally mature T- and B-cells. In Russia, however, its widespread use started only in 2023. Data on the use of this assay in infants with CHDs are represented by isolated case reports. In Russia, a combination of CHD and primary immunodeficiency was found in 37% of cases in the Sverdlovsk Region. We conducted our own study of 200 children with CHD; 5% of cases were syndromic forms of CHD. 48.5% of children were admitted to the cardiac surgery clinic in critical condition. A decrease in the TREC level was detected in 23.5% of cases, including all children with syndromic CHD. In the group of patients with immunological disorders, there were significantly more children with cyanotic CHD, children admitted in critical condition, and children with conotruncal defects. Infectious complications in the postoperative period (sepsis, pneumonia, tracheobronchitis, postoperative wound infection) were observed significantly more often in 47 children with reduced TREC levels compared to children with normal TREC levels (P = .00000, in 36% and 3.6%, respectively). The analysis of publications confirms the prognostic value of TREC and KREC screening for targeted preoperative preparation to reduce postoperative complications and decrease the risk of mortality in CHDs.