Severe combined immunodeficiency (SCID), the most severe form of T-cell immunodeficiency, can be screened at birth by quantifying T-cell receptor excision circles (TRECs) in dried blood spot (DBS) ...samples. Early detection of this condition speeds up the establishment of appropriate treatment and increases the patient's life expectancy. Newborn screening for SCID started in January 2017 in Catalonia, the first Spanish and European region to universally include this testing. The results obtained in the first 2 years of experience are evaluated here. All babies born between January 2017 and December 2018 were screened. TREC quantification in DBS (1.5 mm diameter) was performed with the Enlite Neonatal TREC kit from PerkinElmer (Turku, Finland). In 2018, the retest cutoff in the detection algorithm was updated based on the experience gained in the first year, and changed from 34 to 24 copies/μL. This decreased the retest rate from 3.34 to 1.4% (global retest rate, 2.4%), with a requested second sample rate of 0.23% and a positive detection rate of 0.02%. Lymphocyte phenotype (T, B, NK populations), expression of CD45RA/RO isoforms, percentage and intensity of TCR αβ and TCR γδ, presence of HLA-DR+ T lymphocytes, and
lymphocyte proliferation were studied in all patients by flow cytometry. Of 130,903 newborns screened, 30 tested positive, 15 of which were male. During the study period, one patient was diagnosed with SCID: incidence, 1 in 130,903 births in Catalonia. Thirteen patients had clinically significant T-cell lymphopenia (non-SCID) with an incidence of 1 in 10,069 newborns (43% of positive detections). Nine patients were considered false-positive cases because of an initially normal lymphocyte count with normalization of TRECs between 3 and 6 months of life, four infants had transient lymphopenia due to an initially low lymphocyte count with recovery in the following months, and three patients are still under study. The results obtained provide further evidence of the benefits of including this disease in newborn screening programs. Longer follow-up is needed to define the exact incidence of SCID in Catalonia.
Acylcarnitine and amino acid analyses of dried blood spot (DBS) samples using tandem mass spectrometry in newborn screening (NBS) programmes can generate false positive (FP) results. Therefore, ...implementation of second-tier tests (2TTs) using DBS samples has become increasingly important to avoid FPs. The most widely used 2TT metabolites include methylmalonic acid, 3-hydroxypropionic acid, methylcitric acid, and homocysteine.
We simultaneously measured 46 underivatised metabolites, including organic acids, acylglycine and acylcarnitine isomers, homocysteine, and orotic acid, in DBS samples using tandem mass spectrometry. To validate this method, we analysed samples from 147 healthy newborns, 160 patients with genetic disorders diagnosed via NBS, 20 patients with acquired vitamin B12 deficiency, 10 newborns receiving antibiotic treatment, and nine external quality control samples.
The validation study revealed that 31 metabolites showed good analytical performance. Furthermore, this method detected key metabolites for all diseases associated with increased levels of the following acylcarnitines: C3, C4, C5, C4DC/C5OH, and C5DC. The sensitivity of this method to detect all diseases was 100 %, and the specificity was 74-99 %, except for glutaric aciduria type 1. This method can also be used to diagnose mitochondrial fatty acid β-oxidation disorders (FAODs) and urea cycle defects (UCDs).
We have described a 2TT panel of 31 metabolites in DBS samples based on an easy and rapid method without derivatisation. Its implementation allowed us to distinguish between different organic acidurias, some FAODs, and UCDs. This new strategy has increased the efficiency of our NBS programme by reducing FP and false negative results, second sample requests, and the time required for diagnosis.
Newborn Screening for SCID: Experience in Spain (Catalonia) Argudo-Ramírez, Ana; Martín-Nalda, Andrea; González de Aledo-Castillo, Jose Manuel ...
International journal of neonatal screening,
07/2021, Letnik:
7, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Newborn screening (NBS) for severe combined immunodeficiency (SCID) started in Catalonia in January-2017, being the first Spanish and European region to universally include this testing. In Spain, a ...pilot study with 5000 samples was carried out in Seville in 2014; also, a research project with about 35,000 newborns will be carried out in 2021–2022 in the NBS laboratory of Eastern Andalusia. At present, the inclusion of SCID is being evaluated in Spain. The results obtained in the first three and a half years of experience in Catalonia are presented here. All babies born between January-2017 and June-2020 were screened through TREC-quantification in DBS with the Enlite Neonatal TREC-kit from PerkinElmer. A total of 222,857 newborns were screened, of which 48 tested positive. During the study period, three patients were diagnosed with SCID: an incidence of 1 in 74,187 newborns; 17 patients had clinically significant T-cell lymphopenia (non-SCID) with an incidence of 1 in 13,109 newborns who also benefited from the NBS program. The results obtained provide further evidence of the benefits of early diagnosis and curative treatment to justify the inclusion of this disease in NBS programs. A national NBS program is needed, also to define the exact SCID incidence in Spain.
SARS-CoV-2 nosocomial outbreaks in the first COVID-19 wave were likely associated with a shortage of personal protective equipment and scarce indications on control measures. Having covered these ...limitations, updates on current SARS-CoV-2 nosocomial outbreaks are required. We carried out an in-depth analysis of a 27-day nosocomial outbreak in a gastroenterology ward in our hospital, potentially involving 15 patients and 3 health care workers. Patients had stayed in one of three neighboring rooms in the ward. The severity of the infections in six of the cases and a high fatality rate made the clinicians suspect the possible involvement of a single virulent strain persisting in those rooms. Whole-genome sequencing (WGS) of the strains from 12 patients and 1 health care worker revealed an unexpected complexity. Five different SARS-CoV-2 strains were identified, two infecting a single patient each, ruling out their relationship with the outbreak; the remaining three strains were involved in three independent, overlapping, limited transmission clusters with three, three, and five cases. Whole-genome sequencing was key to understand the complexity of this outbreak. IMPORTANCE We report a complex epidemiological scenario of a nosocomial COVID-19 outbreak in the second wave, based on WGS analysis. Initially, standard epidemiological findings led to the assumption of a homogeneous outbreak caused by a single SARS-CoV-2 strain. The discriminatory power of WGS offered a strikingly different perspective consisting of five introductions of different strains, with only half of them causing secondary cases in three independent overlapping clusters. Our study exemplifies how complex the SARS-CoV-2 transmission in the nosocomial setting during the second COVID-19 wave occurred and leads to extending the analysis of outbreaks beyond the initial epidemiological assumptions.
Faced with the prospect of a collapsed health system
due to the COVID-19 pandemic, the professionals involved
in the Neonatal Screening Programme (NSP) of
Catalonia had to adapt to this situation in ...a flexible, forceful
and efficient manner. The most important goals were
to prevent the risk of infection in the professionals, in families
and their newborns, as well as to ensure the same
effectiveness for the early detection of the diseases included
in our programme.
To this end, the laboratory was reorganised by dividing
the staff into groups and the spaces were redistributed. It
was also necessary to modify several protocols and circuits,
especially for the management of early discharges
from maternity centres, and for the collection of the necessary
second samples (from newborns with inconclusive
results or for low quality samples). In general, a 36%
reduction in the time of arrival of these second samples at
the laboratory was achieved with respect to the previous
circuit. In the specific case of cystic fibrosis detection, the
implementation of a new strategy meant a 100% reduction
in the request for second samples and a 70% reduction in
the age of diagnosis of the newborn.
After evaluating these changes, it can be concluded
that in the face of the pandemic, the NSP of Catalonia
showed determined leadership, aligning all its professionals,
ensuring the continuity of the activity in the programme
and generating new opportunities. The new processes
and circuits implemented have been definitively
consolidated, improving the efficiency of the programme.
Ante la crisis de un sistema sanitario colapsado debido
a la pandemia por la COVID-19, los profesionales
implicados en el Programa de Cribado Neonatal (PCN)
de Cataluña nos tuvimos que adaptar a dicha situación de
forma ágil, contundente y eficiente. Los objetivos prioritarios
fueron prevenir el riesgo de contagio tanto en los
profesionales sanitarios como en las familias y sus recién
nacidos, así como asegurar la misma eficacia para la detección
precoz de las enfermedades incluidas en el PCN.
Para ello, se reorganizó el laboratorio dividiendo en
grupos al personal y se redistribuyeron los espacios.
También fue necesario modificar varios protocolos y circuitos,
en especial para la gestión de las altas precoces
de los centros maternales y para la toma de las segundas
muestras necesarias (de recién nacidos que presentaron
resultados dudosos o por muestra inválida). En general, se
consiguió una reducción del 36% del tiempo de llegada de
estas segundas muestras al laboratorio respecto al circuito
anterior. Para la detección de la fibrosis quística, la implementación
de una nueva estrategia supuso una reducción
del 100% en la solicitud de segundas muestras y del 70%
en la edad de diagnóstico del recién nacido.
Tras la evaluación de estos cambios, se puede concluir
que ante la pandemia el PCN de Cataluña mostró
un liderazgo decidido, alineando a todos sus profesionales,
asegurando la continuidad de la actividad en el programa
y generando nuevas oportunidades. Los nuevos
procesos y circuitos de trabajo implantados han quedado
definitivamente consolidados, mejorando la eficiencia
del programa.
Background: Newborn screening programmes
(NBSP) have experienced a qualitative breakthrough
due to the implementation of tandem mass spectrometry.
However, the tests used give rise to false positives ...(FP)
generating an excessive request for second samples with
the consequent anxiety of the families. In order to avoid this
problem several programmes have developed second-tier
tests (2TT).
Methods: This article presents our experience in the
implementation of 2TT in the NBSP of Catalonia, as well
as in other international programmes.
Results: From 2004 to the present, 2TT tests have been
developed for more than 30 diseases. The use of 2TT helps
to decrease the FP rate and increase the positive predictive
value (PPV). In the NBSP of Catalonia, the implementation
of 2TT for the detection of methylmalonic and propionic
acidemias, homocystinurias, maple syrup disease and citrulinaemia,
has managed to increase the PPV to 95% and decrease
the PF rate to less than 0.01%. In cystic fibrosis, the
application of 2TT slightly increases PPV but with a significant
decrease in the request for second samples and in the
number of cases referred to clinical units.
Conclusions: The introduction of 2TT in the NBSP
allows to reduce considerably the FP, decreases the number
of requested samples, as well as both anxiety and stress
of the families, at the same time that the hospital costs are
reduced and the PPV is increased, improving notably the
efficiency of the NBSP.
Fundamentos: Los programas de cribado neonatal
(PCN) han experimentado un gran avance cualitativo debido
a la implementación de la espectrometría de masas en
tándem. Sin embargo, las pruebas utilizadas dan lugar a falsos
positivos (FP) generando una excesiva solicitud de segundas
muestras con la consiguiente ansiedad de las familias.
Con el fin de evitar este problema diversos programas
han desarrollado pruebas de segundo nivel (2TT).
Métodos: En este artículo se presenta nuestra experiencia
en la implementación de 2TT en el PCN de
Cataluña, así como en otros programas internacionales.
Resultados: Desde el año 2004 hasta la actualidad
se han desarrollado pruebas de 2TT para más de 30 enfermedades.
La utilización de 2TT ayuda a disminuir la tasa
de FP y aumentar el valor predictivo positivo (VPP). En el
PCN de Cataluña, la implementación de 2TT para la detección
de acidemias metilmalónicas y propiónica, homocistinurias,
jarabe de arce y citrulinemia, ha conseguido aumentar
el VPP a un 95% y disminuir la tasa de FP a menos del
0,01%. En la fibrosis quística la aplicación de 2TT aumenta
ligeramente el VPP pero con disminución significativa de
la solicitud de segundas muestras y de los casos referidos a
las unidades clínicas.
Conclusiones: La introducción de los 2TT en los
PCN permite reducir considerablemente los FP, disminuye
el número de muestras solicitadas, así como la ansiedad y
el estrés de las familias, a la vez que se reducen los costes
hospitalarios y se aumenta el VPP, mejorando notablemente
la eficiencia de los PCN.
Severe combined immunodeficiency (SCID), the most
severe form of T-cell immunodeficiency, can be screened
at birth by quantifying T-cell receptor excision circles
(TREC) in dried blood spot (DBS) ...samples. Early detection
of this condition speeds up the establishment of
appropriate treatment and increases the patient’s life expectancy.
Newborn screening for SCID started in January
2017 in Catalonia, the first Spanish and European region
to universally include this testing. The results obtained
in the first three years and a half of experience (January
2017 – June 2020) are shown here, using EnLite Neonatal
TREC kit (Perkin Elmer) with 20 copies/μL as TREC detection
cutoff. Of 222,857 newborns screened, 48 tested
positive: three patients were diagnosed with SCID (incidence
1:74,285); 17 patients had clinically significant
T-cell lymphopenia (non-SCID) with an incidence of 1 in
13,109 newborns; twenty two patients were considered
false-positive cases because of an initially normal lymphocyte
count with normalization of TREC between 3 and
6 months of life; one case had transient lymphopenia due
to an initially low lymphocyte count with recovery in the
following months; and five patients are still under study.
The results obtained provide further evidence of the
benefits of including this disease in newborn screening
programs. Even longer follow-up could be necessary to
define the exact incidence of SCID in Catalonia.
La inmunodeficiencia combinada grave (IDCG) es
la forma más grave de inmunodeficiencia primaria, que
afecta sobre todo a los linfocitos T, y puede ser detectada
al nacer mediante la cuantificación de los círculos de escisión
del receptor de linfocitos T (TREC) en una muestra
de sangre impregnada en papel (DBS). La detección precoz
de esta enfermedad permite establecer de forma temprana
un tratamiento adecuado en el paciente, permitiendo
así su curación. El cribado neonatal de IDCG comenzó
en Cataluña en enero de 2017, siendo la primera región
española y europea en incluirla oficial y universalmente
en su programa. En el presente trabajo se presentan los resultados
obtenidos durante los tres primeros años y medio
de experiencia (enero 2017 – junio 2020) empleando el kit
EnLite Neonatal TREC (Perkin Elmer), con un cutoff de
detección de TREC de 20 copias/μL. De 222.857 recién
nacidos analizados, cuarenta y ocho fueron detecciones
positivas: tres casos de IDCG (incidencia de 1:74.285);
diecisiete casos de linfopenia T no IDCG (incidencia de
1:13.109); veintidós casos falsos positivos (recuento de
linfocitos inicialmente normal, con normalización de
TREC entre los tres y seis meses de vida); un caso con
linfopenia transitoria (con un recuento de linfocitos inicialmente
bajo, que se normaliza en los meses siguientes);
y cinco pacientes se encuentran todavía en estudio.
Los resultados obtenidos aportan evidencias de los beneficios
que supone incluir esta enfermedad en los programas
de cribado neonatal. Podría ser necesario un seguimiento
todavía más prolongado para acabar de definir
la incidencia exacta de IDCG en Cataluña.
The Catalonian Newborn Screening Program
(CNSP) began in 1969, in Barcelona. It was promoted
by Dr. Juan Sabater Tobella and supported
by Barcelona Provincial Council and Juan March
Foundation. That ...is how the Institute of Clinical
Biochemistry was born, whose aims were diagnosis,
research and teaching, along with the spirit of contributing
to the prevention of mental retardation.
The CNSP began with the detection of phenylketonuria
(PKU), and, in 1982, the Program was expanded
with the inclusion of congenital hypothyroidism
detection. Towards 1990, the Program covered
almost 100% of all newborns (NB) in Catalonia.
In 1999, the CNSP was expanded with the incorporation
of cystic fibrosis. It took fourteen years,
until 2013, to make the largest expansion so far,
with the incorporation of 19 metabolic diseases to
the screening panel.
The detection of sickle cell disease began in
2015 and in 2017 the detection of severe combined
immunodeficiency was included.
Currently, the CNSP includes 24 diseases in its
main panel. Since 1969, 2,787,807 NBs have been
screened, of whom 1,724 have been diagnosed with
any of these diseases, and 252 of other disorders
by differential diagnosis with those included in
the main panel. The global prevalence is 1: 1,617
NBs affected by any of the diseases included in the
CNSP and 1: 1,140 NBs if incidental findings diagnosed
through the CNSP are included.
El Programa de Cribado Neonatal de Cataluña
(PCNC) se inició en el año 1969, en Barcelona, impulsado
por el Dr. Juan Sabater Tobella y apoyado
por la Diputación de Barcelona y la Fundación Juan
March. Así nació el Instituto de Bioquímica Clínica
para acometer funciones asistenciales, de investigación
y docencia, con el espíritu de contribuir a la
prevención del retraso mental.
El PCNC se inició con la detección de la fenilcetonuria
(PKU) y en el año 1982 se amplió con
la detección del hipotiroidismo congénito. Hacia el
año 1990 la cobertura territorial llegó casi al 100%
de todos los recién nacidos en Cataluña.
En 1999 se amplió el PCNC con la incorporación
de la fibrosis quística y tras catorce años, en
2013, se realizó la ampliación más numerosa hasta
ahora, con la incorporación de la detección de 19
enfermedades metabólicas hereditarias.
En el año 2015 comenzó la detección de la enfermedad
de células falciformes y en el 2017 la detección
de la inmunodeficiencia combinada grave.
Actualmente, el PCNC incluye la detección de
24 enfermedades. Desde su inicio en el año 1969,
se han cribado 2.787.807 recién nacidos, de los cuales
1.724 han sido diagnosticados de alguna de las
24 enfermedades que componen nuestro panel principal
y 252 por diagnóstico diferencial de las primeras.
En total la prevalencia global es de 1:1.617
RN afectos de alguna de las enfermedades incluidas
en el PCNC y de 1:1.140 RN si se incluyen los hallazgos
incidentales encontrados.
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