scholarly journals When Screening for Severe Combined Immunodeficiency (SCID) with T Cell Receptor Excision Circles Is Not SCID: a Case-Based Review

2021 ◽  
Author(s):  
David Buchbinder ◽  
Jolan E. Walter ◽  
Manish J. Butte ◽  
Wan-Yin Chan ◽  
Maria Chitty Lopez ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Severe Combined Immunodeficiency ◽  
Cell Receptor ◽  
Combined Immunodeficiency ◽  
Excision Circles ◽  
Case Based

Neonatal Lymphopenia Screening Is Important For Early Diagnosis of Severe Combined Immunodeficiency

2021 ◽  
Author(s):  
Aykut Poyraz ◽  
Murat Cansever ◽  
Ipek Muderris ◽  
Turkan Patiroglu
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Umbilical Cord Blood ◽  
Lymphocyte Count ◽  
Blood Count ◽  
Complete Blood Count ◽  
Severe Combined Immunodeficiency ◽  
Cell Receptor ◽  
Combined Immunodeficiency ◽  
Excision Circles

Objective T-cell receptor excision circles are expensive for neonatal severe combined immunodeficiency screening in developing countries. We aimed to detect immunodeficiencies presenting with lymphopenia to enable screening in the general population and to improve awareness regarding lymphopenia among clinicians. Study Design This study was conducted prospectively. In all newborns included, complete blood count from umbilical cord blood samples was recorded. Absolute lymphopenia was defined as absolute lymphocyte count <3,000/mm3 in umbilical cord blood sample. Complete blood count was repeated at month 1 in cases found to have lymphopenia. Results Overall, 2,000 newborns were included in the study. Absolute lymphopenia was detected in 42 newborns (2.1%), while lymphocyte count was >3,000/mm3 in 1,958 newborns (97.9%). Two infants with persisted lymphopenia at the end of the first month; therefore, further evaluations such as lymphocyte subsets for severe combined immunodeficiency (SCID) were done. In the first infant, the lymphocyte subgroups were detected as compatible with T (−), B (−), natural killer cells (NK) (+) SCID phenotype RAG defect. Sanger sequencing revealed that NM_000448 c.2209C > T (p.R737C) homozygous mutation of RAG1 gene. In the other infant, the lymphocyte subgroups were found as considered with T (−), B (+) NK (−) SCID phenotype JAK3 defect. Both patients underwent hematopoietic stem cell transplantation from human leukocyte antigen-matched family member. Conclusion Absolute lymphopenia by complete blood count is a more simpler, relatively noninvasive and inexpensive screening methodfor detection of SCID in newborns compared with T-cell receptor excision circles technique. Key Points

scholarly journals T-cell receptor and K-deleting recombination excision circles in newborn screening of T- and B-cell defects: review of the literature and future challenges

2013 ◽  
Vol 2 (1) ◽  
pp. 3 ◽  
Author(s):  
Marco Chiarini ◽  
Cinzia Zanotti ◽  
Federico Serana ◽  
Alessandra Sottini ◽  
Diego Bertoli ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
T Cell Receptor ◽  
Severe Combined Immunodeficiency ◽  
Cell Receptor ◽  
The United States ◽  
Combined Immunodeficiency ◽  
Blood Spots ◽  
T Cell Lymphopenia ◽  
Excision Circles

Since its introduction as a public health programme in the United States in the early 1960s, newborn blood screening (NBS) has evolved from the detection of phenylalanine levels on filter paper to the application of DNA-based technologies to identify T-cell lymphopenia in infants with severe combined immunodeficiency. This latter use of NBS has required the development of an assay for T-cell lymphopenia based on the quantification of T-cell receptor excision circles (TRECs) that could be performed on dried blood spots routinely collected from newborn infants. The TREC-based NBS was developed six years ago, and there have already been 7 successful pilot studies since then. Similarly, efforts are now being made to establish a screen for B-cell defects, in particular agammaglobulinaemia, taking advantage of the introduction of the method for the quantification of K-deleting recombination excision circles (KRECs). A further achievement of NBS could be the simultaneous recognition of T- and B-cell defects using the combined quantification of TRECs and KRECs from Guthrie card blood spots. This approach may help the early identification of infants with T- and B-cell deficiencies so that they can then be referred to specialised paediatric centres, where a precise diagnosis of severe combined immunodeficiency and agammaglobulinaemia can be performed, and where then they can immediately receive specific therapy. Simultaneous TREC and KREC quantification should also allow classification of patients into subgroups and help identify children with less serious primary immunodeficiencies. This would help avoid the opportunistic infections and frequent hospitalisations that result from a late or lack of diagnosis.

Identification of Severe Combined Immunodeficiency by T-Cell Receptor Excision Circles Quantification Using Neonatal Guthrie Cards

2009 ◽  
Vol 155 (6) ◽  
pp. 829-833 ◽  
Author(s):  
Yoichi Morinishi ◽  
Kohsuke Imai ◽  
Noriko Nakagawa ◽  
Hiroki Sato ◽  
Katsuyuki Horiuchi ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Severe Combined Immunodeficiency ◽  
Cell Receptor ◽  
Combined Immunodeficiency ◽  
Excision Circles ◽  
Guthrie Cards

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

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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