T-cell receptor excision circles (TRECs) as routine newborn screening protocol for severe combined immunodeficiency (SCID)

Severe combined immunodeficiency (SCID) is characterized by the absence of functional T cells and B cells. Without early diagnosis and treatment, infants with SCID die from severe infections within the first year of life.

The researches tried to determined the feasibility of detecting SCID T(-)B(-)NK(+) in newborns by quantitating T-cell receptor excision circles (TRECs) from dried blood spots (DBSs) on newborn screening (NBS) cards (See what a TREC is here).

DNA was extracted from DBSs on deidentified NBS cards, and real-time quantitative PCR (RT-qPCR) was used to determine the number of TRECs.

No TRECs were detected in either the SCID or naive T-cell-depleted samples.

The authors concluded that the use of RT-qPCR to quantitate TRECs from DNA extracted from newborn DBSs is a highly sensitive and specific screening test for SCID. This assay is currently being used in Wisconsin for routine screening infants for SCID.


Severe combined immunodeficiency (SCID) - 4 groups according to T/B/NK cells (click to enlarge the image).

Population-based screening for SCID in neonates: The winner is T-cell receptor excision circles. JACI, 2012. See the TRECs figure here: http://goo.gl/dAXHv

References:

Development of a routine newborn screening protocol for severe combined immunodeficiency. Baker MW, Grossman WJ, Laessig RH, Hoffman GL, Brokopp CD, Kurtycz DF, Cogley MF, Litsheim TJ, Katcher ML, Routes JM. J Allergy Clin Immunol. 2009 May 29. [Epub ahead of print]
Mind Maps: Primary Immunodeficiency (PID)
Video: Universal Newborn Screening for Severe Combined Immunodeficiency (SCID) by Quantitating T Cell Receptor Excision Circles (TRECs). University of Wisconsin.

TRECs are the most accurate noninvasive tool to detect T-cell SCID http://goo.gl/B680e
Screening for T-cell lymphopenia and SCID recommended as an addition to the newborn screening programs in all states. Expert Rev Clin Immunol. 2011 Nov;7(6):761-8.
The state of Wisconsin approach to newborn screening for SCID: 5 infants with SCID detected in 3 years. JACI, 2012.