TRIAGEM NEONATAL DE IMUNODEFICIÊNCIAS GRAVES COMBINADAS POR MEIO DE TRECS E KRECS: SEGUNDO ESTUDO PILOTO NO BRASIL / NEWBORN SCREENING FOR SEVERE COMBINED IMMUNODEFICIENCIES USING TRECS AND KRECS: SECOND PILOT STUDY IN BRAZIL

RESUMO Objetivo: Validar a quantificação de T-cell receptor excision circles (TRECs) e kappa-deleting recombination circles (KRECs) por reação em cadeia de polimerase (polymerase chain reaction, PCR) em tempo real (qRT-PCR), para triagem neonatal de imunodeficiências primárias que cursam com defeitos nas células T e/ou B no Brasil. Métodos: Amostras de sangue de recém-nascidos (RN) e controles foram coletadas em papel-filtro. O DNA foi extraído e os TRECs e KRECs foram quantificados por reação duplex de qRT-PCR. O valor de corte foi determinado pela análise de Receiver Operating Characteristics Curve, utilizando-se o programa Statistical Package for the Social Sciences (SSPS) (IBM®, Armonk, NY, EUA). Resultados: 6.881 amostras de RN foram analisadas quanto à concentração de TRECs e KRECs. Os valores de TRECs variaram entre 1 e 1.006 TRECs/µL, com média e mediana de 160 e 139 TRECs/µL, respectivamente. Três amostras de pacientes diagnosticados com imunodeficiência grave combinada (severe combined immunodeficiency, SCID) apresentaram valores de TRECs abaixo de 4/µL e um paciente com Síndrome de DiGeorge apresentou TRECs indetectáveis. Os valores de KRECs encontraram-se entre 10 e 1.097 KRECs/µL, com média e mediana de 130 e 108 KRECs/µL, e quatro pacientes com diagnóstico de agamaglobulinemia tiveram resultados abaixo de 4 KRECs/µL. Os valores de corte encontrados foram 15 TRECs/µL e 14 KRECs/µL, e foram estabelecidos de acordo com a análise da Receiver Operating Characteristics Curve, com sensibilidade de 100% para detecção de SCID e agamaglobulinemia, respectivamente. Conclusões: A quantificação de TRECs e KRECs foi capaz de diagnosticar crianças com linfopenias T e/ou B em nosso estudo, validando a técnica e dando o primeiro passo para a implementação da triagem neonatal em grande escala no Brasil.

ABSTRACT Objective: To validate the quantification of T-cell receptor excision circles (TRECs) and kappa-deleting recombination excision circles (KRECs) by real-time polymerase chain reaction (qRT-PCR) for newborn screening of primary immunodeficiencies with defects in T and/or B cells in Brazil. Methods: Blood samples from newborns and controls were collected on filter paper. DNA was extracted and TRECs, and KRECs were quantified by a duplex real-time PCR. The cutoff values were determined by receiver operating characteristic curve analysis using SPSS software (IBM®, Armonk, NY, USA). Results: Around 6,881 samples from newborns were collected and TRECs and KRECs were quantified. The TRECs values ranged between 1 and 1,006 TRECs/µL, with mean and median of 160 and 139 TRECs/µL, respectively. Three samples from patients with severe combined immunodeficiency (SCID) showed TRECs below 4/µL and a patient with DiGeorge syndrome showed undetectable TRECs. KRECs values ranged from 10 to 1,097 KRECs/µL, with mean and median of 130 and 108 KRECs/µL. Four patients with agammaglobulinemia had results below 4 KRECs/µL. The cutoff values were 15 TRECs/µL and 14 KRECs/µL and were established according to the receiver operating characteristic curve analysis, with 100% sensitivity for SCID and agammaglobulinemia detection, respectively. Conclusions: Quantification of TRECs and KRECs was able to diagnose children with T- and/or B-cell lymphopenia in our study, which validated the technique in Brazil and enabled us to implement the newborn screening program for SCID and agammaglobulinemia.

Triagem neonatal para imunodeficiência combinada grave / Newborn screening for severe combined immunodeficiency

As imunodeficiências primárias (IDP) são uma área recente e aindapouco conhecida da medicina. Pacientes com IDP apresentam, na maior parte dos casos, infecções graves e recorrentes de início precoce, elevada morbidade e mortalidade, resultando frequentemente em sequelas,elevado custo social e sofrimento dos familiares. Embora na Américado Norte e Europa se estime que sua incidência seja semelhante à dafenilcetonúria e do hipotireoidismo congênito (afecções congênitas quecontam com triagem neonatal), ainda faltam dados quanto à sua real incidência na população brasileira.O projeto em desenvolvimento no Instituto de Ciências Biomédicasda USP e Escola Paulista de Medicina da UNIFESP, visa contribuir para o avanço na implementação de testes de triagem neonatal para asimunodeficiências primárias, mais especificamente, ImunodeficiênciasCombinadas Graves, que constituem um grupo de doenças com diferentesdefeitos genéticos, que evoluem para o óbito precoce se não foremdiagnosticadas e tratadas a tempo e a Síndrome de DiGeorge, que seestima ser a síndrome genética de deleção mais prevalente (1:3.000nascidos vivos).Seguindo esta linha de pensamento, nossa hipótese é que no Brasilexiste um número desconhecido de pacientes com IDP não diagnosticadosou subdiagnosticados que após a implementação de técnicas de detecção molecular por triagem neonatal para a SCID e síndrome de DiGeorge, passarão a ser contabilizados e tratados corretamente, diminuindo portanto,a morbidade e mortalidade.

Primary immunodeficiency disorders (PIDD) are a recently-recognizedand relatively unstudied area of medicine. Patients with PIDD frequentlypresent with the early onset of severe recurrent infections, high morbidityand mortality, frequently resulting in sequelae, high social cost, andfamily burden. While in North America and Europe it is estimated thatits incidence is similar to phenylketonuria and congenital hypothyroidism(congenital disorders that rely on neonatal screening), there is a lack ofdata on its actual incidence in Brazil.The project being developed at Institute of Biomedical Sciences,University of São Paulo and Federal University of São Paulo MedicalSchool, aims to contribute to the implementation of neonatal screeningtests for primary immunodeficiencies. More specifically, severe combinedimmunodeficiencies, a group of diseases with several genetic defects,may progress to early death if not diagnosed and treated early in life;and DiGeorge Syndrome, which is estimated to be the most prevalentgenetic deletion syndrome (1:3,000).Our hypothesis is that, in Brazil there is an unknown number ofpatients with undiagnosed or underdiagnosed disease, which, after theimplementation of detection techniques through newborn screening forSCID and DiGeorge Syndrome, will be accounted for and treated properly,reducing therefore, the morbidity and mortality.

Adenosin deaminasa como molécula coestimuladora y marcador de inmunidad celular / Adenosine deaminase as costimulatory molecule and marker of cellular immunity

La adenosin deaminasa (ADA), es una enzima del metabolismo de las purinas que ha sido objeto de mucho interés debido a que el defecto congénito de esta enzima causa el síndrome de inmunodeficiencia combinada severa. Una de las tres isoformas de la enzima (ecto-ADA) es capaz de unirse a la glicoproteína CD26 y a los receptores de adenosina A1 y A2B. La interacción ADA-CD26 produce una señal coestimuladora en los eventos de activación de las células T y en la secreción de IFN-g, TNF-a e IL-6. Durante dicha activación la actividad de la enzima está regulada de manera positiva por IL-2 e IL-12 y negativamente por IL-4, basado en un mecanismo de translocación. Diversos estudios señalan que los niveles séricos y plasmáticos de ADA se elevan en algunas enfermedades causadas por microorganismos que infectan principalmente a los macrófagos; así como en trastornos hipertensivos, lo cual podría representar un mecanismo compensatorio como consecuencia de la elevación de los niveles de adenosina y la liberación de mediadores hormonales e inflamatorios estimulados por la hipoxia.

Adenosine deaminase (ADA) is an enzyme of purine metabolism which has been the subject of much interest because the congenital defect of this enzyme causes severe combined immunodeficiency syndrome. One of the three isoforms of the enzyme (ecto-ADA) is capable of binding to the glycoprotein CD26 and adenosine receptors A1 and A2B. ADA-CD26 interaction produces a costimulatory signal in the events of T cell activation and secretion of IFN-g, TNF-a and IL-6. During this activation, the enzyme activity is regulated positively by IL-2 and IL-12 and negatively by IL-4, based on the mechanism of translocation. Diverse studies suggest that seric and plasmatic levels of ADA rise in some diseases caused by microorganisms infecting mainly the macrophages and in hypertensive disorders, which may represent a compensatory mechanism resulting from increased adenosine levels and the release of hormones and inflammatory mediators estimulated by hipoxia.

Severe combined immunodeficiency. King Hussein medical center experience

To describe the clinical experience of a single center in severe combined Immunodeficiency. a total of 14 patients who were admitted to the Pediatric Department at King Hussein Medical Center with a probable diagnosis of severe combined immunodeficiency over 6 years duration were studied. The study descried patients' population, clinical, family history, laboratory and radiological investigations, treatment options and prognosis. Twelve [86 percent] patients were males and two [14 percent] were females. Median age at presentation was 21 weeks. They all showed the same clinical presentation with few exceptions. We demonstrated maternofetal engraftment in two [14 percent] patients. Unusual post vaccination poliomyelitis type II was demonstrated in one patient. Skin abscess and deep-seated ulcers were seen in one patient. One patient with Viral Associated Hemophagocytosis Syndrome Dead siblings with similar illness were retrieved in most patients had anemia, lymphopnia, and severe pan-hypogammaglobulinemia at time of presentation. We confirmed neutropenia in only three [21 percent] patients. Blood cultures revealed heavy growth of Klebsiella and Pseudomonas organisms in nine [64 percent] patients. We found that intravenous immunoglobulins administration was partially useful. Bone marrow transplant was not done for any patient. One patient was under preparation for autologous bone marrow transplantation. Eleven patients died after a mean of four months after diagnosis. Two patients were in a relatively acceptable condition, and that last one was suffering from fulminant sepsis. The awareness of the referring physicians to immunodeficiency is sub optimal. Pediatricians are urged to pay attention to persistent Lymphopenia as a helpful clue for the diagnosis of severe combined Immunodeficiency in infants with unusual infections especially in families with positive family history. Live attenuated viral or bacterial immunization is contradicted in suspected immunodeficiency. Health education of families is an essential part of management of these patients