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First pilot study for newborn screening of severe T and B lymphopenias in Colombia
Sebastián Gutiérrez-Hincapié1, Carlos Muskus-López2, Isaura Pilar Sánchez3
1Grupo de Inmunodeficiencias Primarias, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
Insights
This pilot study explored neonatal screening for congenital lymphopenias using T-cell and B-cell receptor excision circles (TREC and KREC). Results showed normal levels in newborns, suggesting the method
Area of Science:
- Immunology
- Neonatal Screening
- Genetics
Context:
- Congenital lymphopenias increase infection susceptibility in newborns.
- Early detection is crucial for timely treatment and preventing severe outcomes.
- Colombia lacks established newborn screening for these conditions.
Purpose:
- To pilot neonatal screening for congenital lymphopenias in Medellín, Colombia.
- To quantify T-cell receptor excision circles (TRECs) and B-cell receptor excision circles (KRECs) in newborn blood samples.
- To establish preliminary cut-off values for TREC and KREC for future screening programs.
Summary:
- Quantified TRECs and KRECs in 1,092 newborns and 6 patients using dried blood spots and qPCR.
- Patients with suspected lymphopenia had undetectable or very low TREC levels.
- Normal TREC and KREC levels were observed in screened newborns; correlations with birth weight and prematurity were noted.
Impact:
- Presents the first preliminary study for early lymphopenia detection in Colombia.
- Proposes TREC and KREC cut-off values (119 and 69 copies/μl, respectively) for national newborn screening.
- Aims to improve early diagnosis, treatment, and outcomes for infants with congenital lymphopenias.
Introduction:
Congenital lymphopenias cause increased susceptibility to infections in children apparently healthy at birth. Earlier detection of these conditions would facilitate prompt treatment, prevent potentially serious disease complications and early deaths, and save healthcare resources.
Objective:
To perform a pilot study for neonatal screening of congenital lymphopenias by the quantification of TREC and KREC –T- and B-cell receptor excision circles– in peripheral blood samples from newborns in Medellín, Colombia.
Materials And Methods:
Blood samples from 1,092 newborns and six referred patients with suspected lymphopenia were collected by heel or toe-finger prick and dropped onto a filter paper. Thereafter, DNA was extracted and levels of TRECs and KRECs were measured by qPCR.
Results:
The six patients with suspected lymphopenia showed undetectable or very low TREC levels. All newborns screened presented normal TREC and KREC levels. A positive correlation was found between TREC or KREC values quantified from two different filter papers. Detectable levels of the receptor excision circles decrease considerably after 24 weeks of the dried blood spot sample storage. We identified a positive association between low TREC levels and low birth weight; and a negative correlation between KREC values and prematurity. Finally, no statistical differences were found between TREC or KREC levels and delivery method.
Conclusion:
We describe the first preliminary study for the early detection of lymphopenias in Colombia. We proposed to use a cut-off value of 119 and 69 copies/μl blood of TREC and KREC, respectively for future newborn screening programs in our country.
