Patients with 22q11.2 deletion are known to have immune abnormalities. Data on the immune profile of non-syndromic patients with conotruncal heart defects are limited.

A prospective study evaluated the genetic and immunological profiles and early to mid-term postoperative outcomes of patients with conotruncal heart defects.

Infants with 22q11.2 deletion had low leukocyte counts, while low total lymphocyte counts were observed in all patients except infants without a genetic syndrome. Reduced CD3+, CD4+, and CD8+ cells were found in 22q11.2 deletion neonates and infants, as well as in infants without a genetic syndrome. Immunoglobulin G, M, and A abnormalities occurred across all groups. T cell receptor excision circle levels were lowest in patients with complex heart defects. Kappa-deleting recombination excision circle levels were increased in patients without a genetic syndrome. Early postoperative infections were frequent in all groups. Neonates with 22q11.2 deletion had longer ICU stay and higher need for antibiotics and hospital readmission at 3 and 6 months of follow-up.

Neonates and infants with conotruncal heart defects have low preoperative T lymphocyte counts, reduced T cell receptor excision circle and immunoglobulin levels, and high incidence of postoperative infections. Higher kappa-deleting recombination excision circle levels compensated the T cell disbalances in patients without a genetic syndrome. The presence of a 22q11.2 deletion with conotruncal heart defects was associated with prolonged mechanical ventilation, longer ICU length of stay, higher need for antibiotic treatment after discharge from the hospital, and readmission risk in neonates after cardiac surgery.