Triagem Neonatal De Imunodeficiências Graves Combinadas Por Meio De Trecs E Krecs: Segundo Estudo Piloto No Brasil

Abstract

Objective: To validate the quantification of T-cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs) by real-time polymerase chain reaction (qRT-PCR) for newborn screening of primary immunodeficiencies with defects in T and/or B cells in Brazil.Methods: Blood samples from newborns and controls were collected on filter paper. DNA was extracted and TRECs, and KRECs were quantified by a duplex real-time PCR. The cutoff values were determined by receiver operating characteristic curve analysis using SPSS software (IBM®, Armonk, NY, USA).Results: Around 6,881 samples from newborns were collected and TRECs and KRECs were quantified. The TRECs values ranged between 1 and 1,006 TRECs/µL, with mean and median of 160 and 139 TRECs/µL, respectively. Three samples from patients with severe combined immunodeficiency (SCID) showed TRECs below 4/µL and a patient with DiGeorge syndrome showed undetectable TRECs. KRECs values ranged from 10 to 1,097 KRECs/µL, with mean and median of 130 and 108 KRECs/µL. Four patients with agammaglobulinemia had results below 4 KRECs/µL. The cutoff values were 15 TRECs/µL and 14 KRECs/µL and were established according to the receiver operating characteristic curve analysis, with 100% sensitivity for SCID and agammaglobulinemia detection, respectively.Conclusions: Quantification of TRECs and KRECs was able to diagnose children with T- and/or B-cell lymphopenia in our study, which validated the technique in Brazil and enabled us to implement the newborn screening program for SCID and agammaglobulinemia.

Newborn Screening for SCID and Other Severe Primary Immunodeficiency in the Polish-German Transborder Area: Experience From the First 14 Months of Collaboration

“…It was especially apparent in children born <28 weeks of gestation. Such observations have been reported in several other publications ( 32 , 50 ). Regarding the KREC values, we did not notice a higher rate of KREC results below cut off in children born <28 weeks of GA.…”

“…In groups of extremely premature and very preterm newborns, the spread of KREC values was greater than in children born ≤ 32 weeks. In a study by Kanegae et al, KREC values did not vary according to GA and in the studies by Barbaro et al and de Felipe et al KREC levels did show a downward trend with decreasing GA ( 25 , 50 ). Further evaluation is needed and may provide data to define the reason for these differences and their clinical implications.…”

A Novel Homozygous JAK3 Mutation Leading to T-B+NK– SCID in Two Brazilian Patients

“…Thus, blood was collected on Guthrie cards and TREC and KREC quantification was used to assess the numbers of naïve T and B cells of Patient 1. While TRECs were undetectable, KRECs were normal (158 molecules / μL of blood) ( 8 ), in accordance with the abnormal lymphocyte's immunophenotyping, which showed a T-B+ profile. Repeated immunophenotyping at age 11 and 12 months revealed decreasing T and NK cell numbers Table 1 .…”

“…Newborn screening for SCID is a reliable, cost-effective and feasible method to reach this goal ( 18 , 19 ). Recently, two articles were published reporting the results of two Brazilian pilot programs on newborn screening using TRECs ( 20 ) and then TRECs and KRECs ( 8 ), demonstrating that the technology and know-how to implement newborn screening is available in Brazil.…”

Diagnostic significance of excision rings of T- and B-cell receptor gene rearrangement for the diagnosis of immune disorders in newborns

“…Нами выявлено снижение уровня TREC у недоношенных детей -127, 5 [58,4; 372,5] Снижение показателей TREC у недоношенных новорожденных подтверждено в зарубежных исследованиях [2,4,18,19]. известно, что уровни TREC во многом зависят от срока гестации и уменьшаются преимущественно у детей, рожденных до 30 недель [2-5, 18, 19].…”