Newborn Screening for Severe Combined Immunodeficiency-A History of the TREC Assay

The incidence of Severe Combined Immunodeficiency (SCID) in Manitoba, (1/15,000), is at least three to four times higher than the national average and that reported from other jurisdictions. It is overrepresented in two population groups: Mennonites (ZAP70 founder mutation) and First Nations of Northern Cree ancestry (IKBKB founder mutation). We have previously demonstrated that in these two populations the most widely utilized T-cell receptor excision circle (TREC) assay is an ineffective newborn screening test to detect SCID as these patients have normal numbers of mature T-cells. We have developed a semi-automated, closed tube, high resolution DNA melting procedure to simultaneously genotype both of these mutations from the same newborn blood spot DNA extract used for the TREC assay. Parallel analysis of all newborn screening specimens utilizing both TREC analysis and the high resolution DNA procedure should provide as complete ascertainment as possible of SCID in the Manitoba population.

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High-Throughput Multiplexed T-Cell–Receptor Excision Circle Quantitative PCR Assay with Internal Controls for Detection of Severe Combined Immunodeficiency in Population-Based Newborn Screening

Clinical Chemistry ◽

10.1373/clinchem.2010.144915 ◽

2010 ◽

Vol 56 (9) ◽

pp. 1466-1474 ◽

Cited By ~ 59

Author(s):

Jacalyn L Gerstel-Thompson ◽

Jonathan F Wilkey ◽

Jennifer C Baptiste ◽

Jennifer S Navas ◽

Sung-Yun Pai ◽

...

Keyword(s):

Quality Assurance ◽

Newborn Screening ◽

T Cell Receptor ◽

Severe Combined Immunodeficiency ◽

Cell Receptor ◽

Population Based ◽

Combined Immunodeficiency ◽

Clinical Validity ◽

Trec Assay ◽

Blood Spot

BACKGROUND Real-time quantitative PCR (qPCR) targeting a specific marker of functional T cells, the T-cell–receptor excision circle (TREC), detects the absence of functional T cells and has a demonstrated clinical validity for detecting severe combined immunodeficiency (SCID) in infants. There is need for a qPCR TREC assay with an internal control to monitor DNA quality and the relative cellular content of the particular dried blood spot punch sampled in each reaction. The utility of the qPCR TREC assay would also be far improved if more tests could be performed on the same newborn screening sample. METHODS We approached the multiplexing of qPCR for TREC by attenuating the reaction for the reference gene, with focus on maintaining tight quality assurance for reproducible slopes and for prevention of sample-to-sample cross contamination. Statewide newborn screening for SCID using the multiplexed assay was implemented, and quality-assurance data were recorded. RESULTS The multiplex qPCR TREC assay showed nearly 100% amplification efficiency for each of the TREC and reference sequences, clinical validity for multiple forms of SCID, and an analytic limit of detection consistent with prevention of contamination. The eluate and residual ghost from a 3.2-mm dried blood spot could be used as source material for multiplexed immunoassays and multiplexed DNA tests (Multiplex Plus), with no disruption to the multiplex TREC qPCR. CONCLUSIONS Population-based SCID newborn screening programs should consider multiplexing for quality assurance purposes. Potential benefits of using Multiplex Plus include the ability to perform multianalyte profiling.

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A Multiplex Immunoassay Using the Guthrie Specimen to Detect T-Cell Deficiencies Including Severe Combined Immunodeficiency Disease

Clinical Chemistry ◽

10.1373/clinchem.2010.144329 ◽

2010 ◽

Vol 56 (9) ◽

pp. 1460-1465 ◽

Cited By ~ 14

Author(s):

David K Janik ◽

Barbara Lindau-Shepard ◽

Anne Marie Comeau ◽

Kenneth A Pass

Keyword(s):

T Cell ◽

Newborn Screening ◽

Clinical Status ◽

Severe Combined Immunodeficiency ◽

Cross Reactivity ◽

Multiplex Assay ◽

Molecular Technique ◽

Combined Immunodeficiency ◽

Pilot Studies ◽

Trec Assay

BACKGROUND Severe combined immunodeficiency (SCID) fulfills many of the requirements for addition to a newborn screening panel. Two newborn screening SCID pilot studies are now underway using the T-cell receptor excision circle (TREC) assay, a molecular technique. Here we describe an immunoassay with CD3 as a marker for T cells and CD45 as a marker for total leukocytes that can be used with the Guthrie specimen. METHODS The multiplexing capabilities of the Luminex platform were used. Antibody pairs were used to capture and detect CD3 and CD45 from a single 3-mm punch of the Guthrie specimen. The assay for each biomarker was developed separately in identical buffers and then combined to create a multiplex assay. RESULTS Using calibrators made from known amounts of leukocytes, a detection limit of 0.25 × 106 cells/mL for CD3 and 0.125 × 106 cells/mL for CD45 was obtained. Affinity tests showed no cross-reactivity between the antibodies to CD3 and CD45. The multiplex assay was validated against 8 coded specimens of known clinical status and linked to results from the TREC assay that had identified them. All were correctly identified by the CD345 assay. CONCLUSIONS The performance parameters of the CD345 assay met the performance characteristics generally accepted for immunoassays. Our assay classifications of positive specimens concur with previous TREC results. This CD345 assay warrants evaluation as a viable alternative or complement to the TREC assay as a primary screening tool for detecting T-cell immunodeficiencies, including SCID, in Guthrie specimens.

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Newborn Screening for Severe Combined Immunodeficiency Using the Multiple of the Median Values of T-Cell Receptor Excision Circles

International Journal of Neonatal Screening ◽

10.3390/ijns7030043 ◽

2021 ◽

Vol 7 (3) ◽

pp. 43

Author(s):

Michael F. Cogley ◽

Amy E. Wiberley-Bradford ◽

Sean T. Mochal ◽

Sandra J. Dawe ◽

Zachary D. Piro ◽

...

Keyword(s):

T Cell ◽

Newborn Screening ◽

T Cell Receptor ◽

Severe Combined Immunodeficiency ◽

Cell Receptor ◽

Combined Immunodeficiency ◽

Individual Test ◽

Copy Numbers ◽

Excision Circles ◽

Trec Assay

All newborn screening programs screen for severe combined immunodeficiency by measurement of T-cell receptor excision circles (TRECs). Herein, we report our experience of reporting TREC assay results as multiple of the median (MoM) rather than using conventional copy numbers. This modification simplifies the assay by eliminating the need for standards with known TREC copy numbers. Furthermore, since MoM is a measure of how far an individual test result deviates from the median, it allows normalization of TREC assay data from different laboratories, so that individual test results can be compared regardless of the particular method, assay, or reagents used.

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Cost-effectiveness of newborn screening for severe combined immunodeficiency

European Journal of Pediatrics ◽

10.1007/s00431-019-03346-3 ◽

2019 ◽

Vol 178 (5) ◽

pp. 721-729 ◽

Cited By ~ 8

Author(s):

Catharina P. B. Van der Ploeg ◽

Maartje Blom ◽

Robbert G. M. Bredius ◽

Mirjam van der Burg ◽

Peter C. J. I. Schielen ◽

...

Keyword(s):

Cost Effectiveness ◽

Newborn Screening ◽

Severe Combined Immunodeficiency ◽

Combined Immunodeficiency

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Newborn Screening for Severe Combined Immunodeficiency: Do Preterm Infants Require Special Consideration?

International Journal of Neonatal Screening ◽

10.3390/ijns7030040 ◽

2021 ◽

Vol 7 (3) ◽

pp. 40

Author(s):

Anne E. Atkins ◽

Michael F. Cogley ◽

Mei W. Baker

Keyword(s):

Newborn Screening ◽

Premature Infant ◽

Gestational Age ◽

Linear Regression Analysis ◽

Severe Combined Immunodeficiency ◽

Cell Receptor ◽

Full Term ◽

Combined Immunodeficiency ◽

Term Infants ◽

Preterm Newborns

The Wisconsin Newborn Screening (NBS) Program began screening for severe combined immunodeficiency (SCID) in 2008, using real-time PCR to quantitate T-cell receptor excision circles (TRECs) in DNA isolated from dried blood NBS specimens. Prompted by the observation that there were disproportionately more screening-positive cases in premature infants, we performed a study to assess whether there is a difference in TRECs between full-term and preterm newborns. Based on de-identified SCID data from 1 January to 30 June 2008, we evaluated the TRECs from 2510 preterm newborns (gestational age, 23–36 weeks) whose specimens were collected ≤72 h after birth. The TRECs from 5020 full-term newborns were included as controls. The relationship between TRECs and gestational age in weeks was estimated using linear regression analysis. The estimated increase in TRECs for every additional week of gestation is 9.60%. The 95% confidence interval is 8.95% to 10.25% (p ≤ 0.0001). Our data suggest that TRECs increase at a steady rate as gestational age increases. These results provide rationale for Wisconsin’s existing premature infant screening procedure of recommending repeat NBS following an SCID screening positive in a premature infant instead of the flow cytometry confirmatory testing for SCID screening positives in full-term infants.

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