TREC and KREC profiles in patients with inborn errors of immunity

Abstract

TREC/KREC analysis is utilized in neonatal screening for the detection of primary immunodeficiencies caused by genetic defects in proteins essential for T- and B-lymphocyte development. However, the diagnostic value of this method for the postnatal detection of various primary immunodeficiency forms has not yet been fully established. This study aimed to analyze the TREC/KREC profiles in patients with confirmed inborn errors of immunity. TREC/KREC levels were assessed in 44 patients using real-time PCR at the time of diagnosis. Nine patients were diagnosed with severe combined immunodeficiency (SCID), 25 with syndromic combined immunodeficiency, five with immune dysregulation disorders, and five with antibody production defects. Abnormal TREC/KREC values were observed in 100% of children with classical SCID, 56% with syndromic immunodeficiencies, and 80% with antibody production defects. Sub-threshold TREC/KREC levels were found in 55.6% of children with Louis-Bar syndrome, 40% with DiGeorge syndrome, and both patients with Nijmegen syndrome. Normal TREC levels were observed in two children with Wiskott-Aldrich syndrome, in cases of immune regulation disorders, and in isolated cases of Job syndrome and hyper-IgM syndrome. The lowest TREC values were identified in patients with combined immunodeficiency. These findings support the potential of the TREC/KREC assay as a tool for postnatal screening, including for patients with late-onset inborn errors of immunity.