Development of a routine newborn screening protocol for severe combined immunodeficiency - 15/08/11
, William J. Grossman, MD, PhD c, Ronald H. Laessig, PhD a, Gary L. Hoffman, BS a, Charles D. Brokopp, DrPH a, Daniel F. Kurtycz, MD a, Michael F. Cogley, BS a, Thomas J. Litsheim, BS a, Murray L. Katcher, MD, PhD b, d, John M. Routes, MD c
Reprint requests: Mei W. Baker, MD, University of Wisconsin School of Medicine and Public Health, 465 Henry Mall, Madison, WI 53706.Abstract |
Background |
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.
Objective |
To determined the feasibility of detecting SCID in newborns by quantitating T-cell receptor excision circles (TRECs) from dried blood spots (DBSs) on newborn screening (NBS) cards.
Methods |
DNA was extracted from DBSs on deidentified NBS cards, and real-time quantitative PCR (RT-qPCR) was used to determine the number of TRECs. Positive controls consisted of DBS from a 1-week-old T−B−NK+ patient with SCID and whole blood specimens selectively depleted of naive T cells.
Results |
The mean and median numbers of TRECs from 5766 deidentified DBSs were 827 and 708, respectively, per 3.2-mm punch (
3 μL whole blood). Ten samples failed to amplify TRECs on initial analysis; all but 1 demonstrated normal TRECs and β-actin amplification on retesting. No TRECs were detected in either the SCID or naive T-cell–depleted samples, despite the presence of normal levels of β-actin.
Conclusions |
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.
Le texte complet de cet article est disponible en PDF.Key words : Dried blood spots, hematopoietic stem cell transplantation, newborn screening, real-time quantitative PCR, severe combined immunodeficiency, T-cell receptor excision circles
Abbreviations used : DBS, HSCT, NBS, NK, PBMCs, RT-qPCR, SCID, TREC, WBC
Plan
| Supported by the Jeffrey Modell Foundation, the Children’s Hospital of Wisconsin Foundation, the Children’s Research Foundation, and the Wisconsin State Laboratory of Hygiene. |
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| Disclosure of potential conflict of interest: M. W. Baker has received research support from the Jeffrey Modell Foundation and the Centers for Disease Control and Prevention. W. J. Grossman is an employee of Merck & Co and has received research support from the National Institutes of Health and the Midwest Athletes Against Childhood Cancer (MACC) Fund. R. H. Laessig has received research support from the Jeffrey Modell Foundation and has provided legal consultation or expert witness testimony in a case related to methodology. J. M. Routes has received research support from the National Institutes of Health and Baxter Pharmaceuticals. The rest of the authors have declared that they have no conflict of interest. |
Vol 124 - N° 3
P. 522-527 - septembre 2009 Retour au numéro
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