Clinical and Genetic Spectrum of Inborn Errors of Immunity in a Tertiary Care Center in Southern India

Objectives To study the incidence, clinical manifestations, and genetic spectrum of primary immunodefciency diseases (PID)/inborn errors of immunity (IEI) in a tertiary care hospital in Southern India. Methods A retrospective analysis of all patients with a clinical suspicion of PID/IEI seen at a tertiary care hospital was performed. All patients had at least one or more warning signs of PID. Serum immunoglobulin levels and other targeted investigations were performed as warranted by the clinical presentation. All families with suspected PID were counseled and ofered genetic testing. Results A total of 225 children were evaluated for PID during the study period of 6 y. Fifty-six of them did not meet the European Society of Immunodefciencies (ESID) criteria (working defnition of clinical diagnosis) and were excluded. An IEI was found in 30/49 (61.2%) patients. The most frequent reason for referral was recurrent/unusual or serious infections (28%), or cytopenia (16%). Group IV diseases of immune dysregulation was the most common category (19%), followed by group III predominant antibody defciencies in 23/163 (14%), as per the International Union of Immunological Societies (IUIS) classifcation. Conclusions This study highlights the heterogeneity of the present cohort, the underuse of genetic tests, and eforts to provide optimal care for children with possible IEI in this center.

Linfoma de Burkitt como complicación de la agammaglobulinemia de Bruton / Burkitt's lymphoma as a complication of Bruton's Agammaglobulinemia

Introducción: La agammaglobulinemia de Bruton es una inmunodeficiencia primaria (IDP) originada por una mutación del gen que codifica la tirosina kinasa de Bruton (BTK). Se sospecha principalmente en varones con infecciones frecuentes de las vías respiratorias y tiene entre otras complicaciones, los tumores, fundamentalmente linfoproliferativos. Se reportan agammaglobulinemias autosómicas recesivas con similares características clínicas en ambos sexos. Objetivo: Presentar el primer caso pediátrico reportado en Cuba, con diagnóstico de linfoma de Burkitt asociado a esta inmunodeficiencia primaria y que además utilizó tratamiento combinado sustitutivo de inmunoglobulinas y antitumoral. Presentación del caso: Paciente masculino, que a los 2 años se le realizó diagnóstico de enfermedad de Bruton. Con el tratamiento de reemplazo con inmunoglobulina endovenosa (Intacglobín) se mantuvo tres años sin infecciones graves. A los 5 años de edad presentó linfoma de Burkitt, tratado con poliquimioterapia, según el esquema AEIOP al que se asoció rituximab. Aunque no se dispone de la detección por biología molecular de la mutación del gen BTK, la disminución por debajo del 2 por ciento de las células B CD19+ y los valores ausentes de IgG, IgA e IgM permitieron el diagnóstico. Conclusión: Coexistieron con resultados clínicos satisfactorios el tratamiento antitumoral y la terapia de reemplazo con inmunoglobulina endovenosa. El paciente se mantiene con buen estado general(AU)

Introduction: Bruton's Agammaglobulinemia is a primary immunodeficiency (PID) caused by a mutation in the gene that encodes Bruton's tyrosine kinase (BTK). It is suspected mainly in men with frequent respiratory tract infections and has, among other complications, tumors, mainly lymphoproliferative. Autosomal recessive agammaglobulinemias with similar clinical characteristics have been reported in both sexes. Objective: To present the first pediatric case reported in Cuba, with a diagnosis of Burkitt's lymphoma associated with PID and that also used combined immunoglobulin replacement and antitumor therapy. Case report: 2-year-old male diagnosed with Bruton's disease. With the replacement treatment with intravenous immunoglobulin (Intacglobin), he maintained three years without serious infections. At 5 years of age, he presented Burkitt's lymphoma, treated with polychemotherapy according to the AEIOP scheme, associating Rituximab. Although do not have molecular biology detection of the BTK gene mutation, the decrease of CD19 + B cells to below 2 percent and the absent values of IgG, IgA and IgM allowed the diagnosis. Conclusion: Antitumor treatment and intravenous immunoglobulin replacement therapy coexisted with satisfactory clinical results. The patient remains in good general condition(AU)

Human Inborn Errors of Immunity (HIEI): predominantly antibody deficiencies (PADs): if you suspect it, you can detect it

Abstract Objective: This minireview gathers the scientific foundations of the literature on genetic errors in the development of the humoral immune system to help pediatricians suspect these defects. Sources: A systemic search using the PubMed MEDLINE database was performed for all Predominantly Antibody Deficiencies (PADs) described in the 2020 IUIS Expert Committee for PID classification system, combined with terms for hypogammaglobulinemia. Search terms for PADs were based on the listed names and affected genes as classified by the IUIS 2020. Abstracts of the results were reviewed to find relevant case series, review articles of PADs associated with infection, opportunistic infection, autoimmunity, cytopenias, malignancies, inflammatory diseases, neurological and respiratory diseases. References from relevant articles were further reviewed for additional references. Relevant findings were grouped in accordance with the IUIS 2020 classification system. Clinical and genetic features, if known, were described. Data synthesis: PADs refer to impaired antibody production due to molecular defects intrinsic to B cells or a failure of interaction between B and T cells. The patients develop recurrent or chronic infection or respond to the antigens with dysregulation of the immune function, causing severe allergy, autoimmunity, inflammation, lymphoproliferation and malignancy. The diagnosis is a combined exercise of clinical and laboratory investigation similar to that performed by Bruton (1952). In the context of SARS-CoV-2 infection, the experience of XLA and CVID patients has been surprising. Variants in 39 genes were reported as causing PADs, but the clinical heterogeneity within each variant is not clear. Conclusion: Bruton (1952) used clinical expertise and protein electrophoresis to identify XLA. The IUIS (2020) committee used immunoglobulins and B lymphocyte to characterize PADs. Pediatricians should suspect it to detect it and prevent morbidities that can have an astonishing and irreversible impact on the child's life.

Infecção por SARS-CoV-2 em paciente com agamaglobulinemia ligada ao X tratado com altas doses de imunoglobulina endovenosa e plasma de convalescente / SARS-CoV-2 infection in a patient with X-linked agammaglobulinemia treated with high doses of intravenous immunoglobulin and convalescent plasma

A pandemia pelo vírus SARS-CoV-2 atingiu adultos, crianças e penalizou indivíduos idosos e com comorbidades como diabetes, doença cardíaca, hipertensão e obesidade. A maioria dos infectados são assintomáticos ou têm sintomas leves, entretanto 15% podem apresentar pneumonia e 5% síndrome respiratória aguda grave. Apresentamos um caso de agamaglobulinemia ligada ao X (XLA) em paciente masculino de 27 anos que se infectou com SARS-CoV-2. Os pacientes com XLA não possuem linfócitos B e não produzem anticorpos devido a uma mutação no gene Bruton tirosino-quinase (BTK), responsável pela maturação dos linfócitos B. Ele infectou-se e foi internado em hospital de Ivoti/RS. A evolução da pneumonia foi rápida, necessitando transferência para o Hospital de Clínicas de Porto Alegre (HCPA) no 10° dia de evolução. Iniciou com infusão de imunoglobulinas, tendo utilizado o total de 400 gramas devido ao intenso catabolismo da IgG, mantendo-se sua concentração entre 700-900 mg/dL. Necessitou de ventilação mecânica, oxigenação por membrana extracorpórea (ECMO) e hemodiálise. Foi administrado plasma de convalescente (PC), 300 mL, por duas vezes, com melhora clínico-radiológica e retirada da ventilação mecânica. Piorou e repetiu outras 4 infusões de PC (total de 1717 mL), negativando o vírus na orofaringe (RT-PCR). Em 3 ocasiões teve sepse, debelada rapidamente. Apresentou anemia, com necessidade de transfusão frequente. Identificou-se linfopenia de CD3, CD4, CD8, NK e ausência de linfócitos B. A linfopenia foi revertida com a recuperação clínica e a alta hospitalar aconteceu no 70° dia de internação.

The SARS-CoV-2 pandemic has affected adults and children and penalized older people and those with comorbidities such as diabetes, heart disease, hypertension and obesity. Most of those infected are asymptomatic or have mild symptoms, but 15% may have pneumonia and 5% acute respiratory distress syndrome. We report a case of X-linked agammaglobulinemia (XLA) in a 27-yearold man who was infected with SARS-CoV-2. XLA patients do not have B lymphocytes and do not produce antibodies because of mutations in the Bruton tyrosine-kinase gene, responsible for the maturation of B cells. This patient was infected and then admitted to a hospital in Ivoti, southern Brazil. Pneumonia progressed rapidly, requiring transfer to the Hospital de Clínicas de Porto Alegre on the 10th day. Intravenous immunoglobulin infusions were initiated, using a total of 400 grams because of an intense catabolism of IgG, and the concentration was kept around 700- 900 mg/dL. Mechanical ventilation, extracorporeal membrane oxygenation and hemodialysis were necessary. Convalescent plasma (CP) was administered (2x300 mL) and then followed by clinical and radiological improvement and interruption of mechanical ventilation. Then he got sicker and had to return to invasive support and received 4 extra CP infusions (total of 1717 mL), until a negative reverse-transcriptase polymerase chain reaction (RT-PCR) for SARS-CoV-2 was obtained. On 3 occasions he had sepsis, promptly managed. He had anemia, requiring frequent transfusion, and lymphopenia (CD3, CD4, CD8, NK), with absence of B lymphocytes. Lymphopenia was reverted during recovery, and he was discharged from the hospital on the 70th day.

La citometría de flujo como auxiliar en el diagnóstico de las inmunodeficiencias primarias humorales / Flow-cytometry as an auxiliary in the diagnosis of primary humoral immunodeficiencies

Resumen Antecedentes: Las deficiencias de anticuerpos abarcan un amplio espectro de patologías y constituyen aproximadamente 50 % de las inmunodeficiencias primarias; con la citometría es posible evaluar el estado inmunológico de forma rápida, efectiva y a bajo costo. Objetivo: Evaluar mediante citometría de flujo, las células de pacientes con tres tipos de inmunodeficiencias primarias humorales. Método: Mediante citometría de flujo se analizaron muestras de sangre de pacientes y sujetos sanos con distintos anticuerpos monoclonales. Resultados: Mediante diversas tinciones se demostró disminución severa de linfocitos B en pacientes con agammaglobulinemia ligada al cromosoma X, la falta de expresión de CD154 en pacientes con síndrome de hiperinmunoglobulina M y heterogeneidad de subpoblaciones de linfocitos B en pacientes con inmunodeficiencia común variable. Conclusión: Con la citometría de flujo es posible realizar el diagnóstico temprano de inmunodeficiencias primarias con un nivel de confianza elevado y, en muchos casos, identificar los genes implicados.

Abstract Background: Antibody deficiencies encompass a wide spectrum of pathologies and constitute approximately 50 % of primary immunodeficiencies; with cytometry, it is possible to evaluate the immune status rapidly, effectively and at low cost. Objective: To assess, by means of flow cytometry, the cells of patients with three types of primary humoral immunodeficiencies. Method: Using flow cytometry, blood samples from patients and healthy subjects were analyzed with different monoclonal antibodies. Results: Using various stains, a severe decrease in B lymphocytes was shown in patients with X-linked agammaglobulinemia, as well as a lack of CD154 expression in patients with hyper-immunoglobulin M syndrome, and heterogeneity of B lymphocyte subpopulations in patients with common variable immunodeficiency. Conclusion: Flow cytometry enables early diagnosis of primary immunodeficiencies with a high level of confidence and, in many cases, identification of the genes involved.

Diagnóstico genético de pacientes con agammaglobulinemia primaria atendidos en centros peruanos de tercer nivel / Genetic diagnosis of patients with primary agammaglobulinemia treated at third level peruvian centers

Las agammaglobulinemias primarias (AP) resultan de alteraciones específicas en las células B, lo cual, conduce a baja producción de anticuerpos. La sospecha diagnóstica se establece con el antecedente de infecciones a repetición, inmunoglobulinas bajas y la ausencia linfocitos B CD19+. El diagnóstico se confirma mediante el análisis genético y la detección de una mutación ligada en el cromosoma X o autosómico recesiva o dominante. En Perú, no hay literatura sobre AP ni reportes sobre el genotipo de los pacientes con sospecha de AP. Bajo este escenario, se realizó un estudio que describió el genotipo de pacientes con sospecha de AP. Se encontraron 20 pacientes con mutaciones en el gen BTK y una mutación autosómica recesiva IGHM. Se hallaron 13 mutaciones hereditarias y siete mutaciones de novo. Se concluye que las AP son, en su mayoría, mutaciones en el gen BTK que corresponden con AP ligadas al cromosoma X.

Primary agammaglobulinemia result from specific alterations in B cells, which lead to low antibody production. Diagnostic suspicion is established with a history of repeated infections, low immunoglobulins, and absence of CD19+ B lymphocytes. The diagnosis is confirmed by genetic analysis and the detection of a mutation linked to the X or autosomal recessive or dominant chromosome. In Peru, there is no literature on primary agammaglobulinemia and no reports on the genotype of patients with suspected primary agammaglobulinemia. Under this scenario, a study was performed to describe the genotype of patients with suspected primary agammaglobulinemia. Twenty (20) patients were found with mutations in the BTK gene and an autosomal recessive IGHM mutation. Thirteen (13) hereditary mutations and seven de novo mutations were found. It is concluded that the group of primary agammaglobulinemia are mostly mutations in the BTK gene, corresponding to X-linked agammaglobulinemia.

Clinical, immunological and genetic characteristic of patients with clinical phenotype associated to LRBA-deficiency in Colombia / Características clínicas, inmunológicas y genéticas de pacientes con el fenotipo asociado a deficiencia LRBA en Colombia

Abstract Background: LPS-responsive beige -like anchor protein (LRBA) deficiency is a primary immunodeficiency disease caused by loss of LRBA protein expression, due to biallelic mutations in LRBA gene. LRBA deficiency patients exhibit a clinically heterogeneous syndrome. The main clinical complication of LRBA deficiency is immune dysregulation. Furthermore, hypogammaglobulinemia is found in more than half of patients with LRBA-deficiency. To date, no patients with this condition have been reported in Colombia Objective: To evaluate the expression of the LRBA protein in patients from Colombia with clinical phenotype associated to LRBA-deficiency. Methods: In the present study the LRBA-expression in patients from Colombia with clinical phenotype associated to LRBA-deficiency was evaluated. After then, the clinical, the immunological characteristics and the possible genetic variants in LRBA or other genes associated with the immune system in patients that exhibit decrease protein expression was evaluated. Results: In total, 112 patients with different clinical manifestations associated to the clinical LRBA phenotype were evaluated. The LRBA expression varies greatly between different healthy donors and patients. Despite the great variability in the LRBA expression, six patients with a decrease in LRBA protein expression were observed. However, no pathogenic or possible pathogenic biallelic variants in LRBA, or in genes related with the immune system were found. Conclusion: LRBA expression varies greatly between different healthy donors and patients. Reduction LRBA-expression in 6 patients without homozygous mutations in LRBA or in associated genes with the immune system was observed. These results suggest the other genetic, epigenetic or environmental mechanisms, that might be regulated the LRBA-expression.

Resumen Antecedentes: la deficiencia de LRBA (del inglés, LPS-responsive beige -like anchor protein) es una inmunodeficiencia primaria causada por la pérdida de la expresión de la proteína LRBA, debido a mutaciones bialélicas en el gen LRBA. Los pacientes con deficiencia de LRBA exhiben un síndrome clínicamente heterogéneo. La principal complicación clínica de la deficiencia de LRBA es la desregulación inmune. Además, la hipogammaglobulinemia se encuentra en más de la mitad de los pacientes con deficiencia de LRBA. Hasta la fecha, no se han reportado pacientes con esta afección en Colombia Objetivo: Evaluar la expresión de la proteína LRBA en pacientes de Colombia con fenotipo clínico asociado a deficiencia de LRBA Métodos: En el presente estudio se evaluó la expresión de LRBA en pacientes de Colombia con fenotipo clínico asociado a deficiencia de LRBA. Después de eso, se evaluaron las características clínicas, inmunológicas y las posibles variantes genéticas en LRBA o en otros genes asociadados con el sistema inmune en pacientes que exhiben una disminución de la expresión de la proteína. Resultados: En total, se evaluaron 112 pacientes con diferentes manifestaciones clínicas asociadas al fenotipo clínico LRBA. La expresión de LRBA varía mucho entre diferentes donantes sanos y pacientes. A pesar de la gran variabilidad en la expresión de LRBA, se observaron seis pacientes con una disminución en la expresión de la proteína LRBA. Sin embargo, no se encontraron variantes bialélicas patógenas o posibles patógenas en LRBA, o en genes relacionados con el sistema inmune. Conclusión: La expresión de LRBA varía mucho entre diferentes donantes sanos y pacientes. Se observó reducción de la expresión de LRBA en 6 pacientes sin mutaciones homocigotas en LRBA o en genes asociados. Estos resultados sugieren los otros mecanismos genéticos, por ejemplo epigenéticos o ambientales, que podrían estar regulados por la expresión de LRBA

Agammaglobulinemia ligada al cromosoma X, lo crucial del diagnóstico y tratamiento oportunos / Agammaglobulinemia linked to the X chromosome, the crucial of timely diagnosis and treatment

INTRODUCCIÓN. La Agammaglobulinemia ligada al cromosoma X es un tipo de inmunodeficiencia primaria originada por una mutación en el gen que codifica a la proteína responsable del proceso madurativo de los linfocitos B, provocando la disminución o ausencia de inmunoglobulinas en sangre periférica y la predisposición a procesos infecciosos a repetición, sobre todo a nivel del tracto respiratorio y digestivo. La sospecha clínica orienta la solicitud de pruebas complementarias de forma secuencial. El tratamiento consiste en la administración sustitutiva de por vida de inmunoglobulina humana. CASO CLÍNICO. Se presentó el caso de un niño de 8 años de edad con infecciones respiratorias altas y bajas a repetición, con estudios radiográficos de tórax que revelaron una atelectasia persistente, en quien la sospecha clínica dio paso a los evaluativos inmunológico y genético. RESULTADOS. El diagnóstico fue realizado a los 6 años de edad con recuento sérico de inmunoglobulinas por debajo del rango para la edad, citometría de flujo con CD19+ del 0,08% y genética con mutación del gen BTK. Se instauró tratamiento con Inmunoglobulina humana a 400 mg/Kg cada 4 semanas, se monitorizó los niveles de IgG antes de cada infusión. DISCUSIÓN. La Agammaglobulinemia ligada al cromosoma X constituye una enfermedad poco prevalente e infradiagnosticada en la que la sospecha clínica representa la base del abordaje, lo que permitió el tratamiento sustitutivo apropiado. CONCLUSIÓN. El diagnóstico y tratamiento oportunos permitieron evitar el desarrollo de infecciones respiratorias graves, mejorar la calidad de vida del niño y el asesoramiento genético familiar.

INTRODUCTION. X-linked Agammaglobulinemia is a type of primary immunodeficiency caused by a mutation in the gene that encodes the protein responsible for the maturation process of B lymphocytes, causing the decrease or absence of immunoglobulins in peripheral blood and the predisposition to repeated infectious processes, especially at the level of the respiratory and digestive tracts. Clinical suspicion guides the request for complementary tests sequentially. The treatment consists of lifelong substitute administration of human immunoglobulin. CASE REPORT. The case of an 8-year-old boy with repeated high and low respiratory infections was presented, with chest radiographic studies that revealed persistent atelectasis, in whom clinical suspicion gave way to immunological and genetic evaluations. RESULTS. The diagnosis was made at 6 years of age with serum immunoglobulin counts below the age range, flow cytometry with CD19 + of 0,08% and genetics with BTK gene mutation. Treatment with human Immunoglobulin at 400 mg / Kg every 4 weeks was initiated, IgG levels were monitored before each infusion. DISCUSSION. X- linked Agammaglobulinemia is a rare and underdiagnosed disease in which clinical suspicion represents the basis of the approach, which allowed for appropriate replacement. CONCLUSION. Timely diagnosis and treatment allowed to avoid the development of serious respiratory infections, improve de child ́s quality of life and family genetic couseling.

Approach to the patient with vitamin D-deficient osteomalacia due to X-linked agammaglobulinemia / 中华内分泌代谢杂志

Osteomalacia is a metabolic bone disease characterized by impaired mineralization of bone matrix. VitaminD deficiency contributes to a decrease in the efficiency of intestinal calcium and phosphorus absorption, resulting in secondary hyperparathyroidism and an inadequate calcium-phosphorus product, thereby causing osteomalacia. We present a patient who was diagnosed as vitamin D-deficient osteomalacia due to X-linked agammaglobulinemia ( XLA) , and the genetic analysis of the BTK gene revealed a missense mutation ( c.82C>T) . It should be attached great importance to etiological analysis of osteomalacia, and XLA may also be a cause of vitamin D deficiency.

Retinite por citomegalovírus em paciente com Síndrome de Good / Cytomegalovirus retinitis in Good Syndrome

Resumo A Síndrome de Good é uma síndrome paraneoplásica caracterizada pela associação de timoma e hipogamaglobulinemia, cursando com imunossupressão. Relatamos um caso raro de retinite por citomegalovírus em paciente com esta síndrome.

Abstract Good syndrome is a paraneoplastic syndrome characterized by the association of thymoma and hypogammaglobulinemia, with immunosuppression. We report a rare case of cytomegalovirus retinitis in a patient with this syndrome.

Paraparesis, leucodystrophy and brain atrophy are neurological manifestations of congenital immunodeficiency disease? / 中华实用儿科临床杂志

A 4-year-old boy complained of weakness of the lower limbs for one and a half month.The child had been diagnosed as X-linked agammaglobulinemia (XLA) at 1-year old.In recent one and a half month,he gradually suffered from activity intolerance and fatigue,inability to jump and run,staggering gait and slow speech.All the symptoms above indicated deteriorating motor function.The brain magnetic resonance imaging revealed abnormal signals in white matter and brain atrophy.The cerebrospinal fluid analysis detected the presence of oligoclonal immunoglobulin G band.In short term after intravenous immunoglobulin and methylprednisolone treatment,the boy's lower extremity function and speech speed were slightly improved.However,at 1-year follow-up,the boy's condition became even worse.The child could not sit without support and had difficulty in swallowing.The child could not speak or follow any commands.Neurological examination revealed spastic quadriplegia and pseudobulbar palsy.Progressive neurodegeneration is not a common syndrome in patients with XLA.Brain biopsy is an important approach clinically to find out etiology.

X-linked agammaglobulinemia in children / 中华实用儿科临床杂志

X-linked agammaglobulinemia (XLA) is one of the most common types of primary immunodeficiency disease in children,and is an antibody deficiency disease which is seen in men.Most XLA patients carry mutations in Bruton tyrosine kinase (BTK) gene,they typically present with very low numbers of peripheral B cells and a profound deficiency of all immunoglobulin isotypes.XLA is characterized by recurrent bacterial infections within 2 years,sometimes life-threatening.The prognosis of XLA has been improved by the treatment of gammaglobulin that allow normal concentrations of serum IgG.

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.

Two families of X-linked lymphoproliferative disease type 1 characterized by agammaglobulinemia / 中华儿科杂志

Objective@#To investigate the clinical and immunological laboratory features, mutations in SH2D1A gene and SAP protein expression in four children of two families with X-linked lymphoproliferative disease type 1(XLP-1).@*Method@#Four patients (Family A including Patient 1 and Patient 2, Family B including Patient 3 and Patient 4) and their maternal relatives were enrolled in this study. The clinical manifestation, EBV infection status and chest CT scan were analyzed. The absolute and relative numbers of lymphocyte subsets, T lymphocyte proliferative response, SAP protein expression were assessed by flow cytometry. Quantification of signal joint TCR rearrangementexcision circle (sjTRECs), CDR3 spectratyping of TCRvβ and gene mutation of SH2D1A were detected by PCR based on genomic DNA or cDNA.@*Result@#Four male patients from two families were diagnosed with XLP-1. The ages of disease onset were more than 1 year, more than 1 year, more than 1 month and 6 months. The ages at diagnosis were nine years and ten months, sixteen years and eight months, fourteen years and ten months, four years and nine months. All patients had recurrent infections and EBV infection. Patients 1, 2, and 3 had agammaglobulinemia and Patient 4 had hypogammaglobulinemia. Chest CT scan showed all patients had atelectasis and pneumonia, and Patient 3 had bronchiectasis. Patient 3 was diagnosised as Burkitt lymphoma. For immunological function, all patients exhibited reduced CD4/CD8 ratios, increased numbers of exhausted T lymphocyte, decreased number of NK cell. The numbers of total B lymphocyte and naïve B lymphocyte were normal, but the number of memory B lymphocyte declined in all cases. Four patients′ copy numbers of sjTRECs were low and CDR3 spectratypings of TCRvβ showed mildly skewed. But their T lymphocyte proliferative response was normal. SAP protein expression in four cases were measured by flow cytometry. Two patients from Family A were absent and two patients from Family B showed decreased values. SH2D1A gene sequence analysis showed that the patients of Family A harbored a nonsense mutation (c.163 C>T; p.R55X) in exon 2. Their mother and two sisters were carriers. A missense mutation of SH2D1A gene (c.278 G>A; p.G93D) in exon 3 was found in the patients of Family B. The mother was carrier. Four patients remain survived, Patient 3 gave up treatment, other three patients received IVIG therapy.@*Conclusion@#Four patients with XLP-1 from two families characterized by agammaglobulinemia have an extreme vulnerability to Epstein-Barr virus (EBV) infection. The functions of T cell, B cell and NK cell are impaired at different stages. The detection of SAP protein and SH2D1A gene are the key methods for diagnosis of XLP-1.

Linfadenite recorrente. Caso clínico / Recurrent lymphadenitis. Case report

A imunodeficiência de variável comum é uma imunodeficiência primária de apresentação heterogênea, consistindo em um défice em imunoglobulinas. É caracterizada por infeções de repetição e predisposição para doenças autoimunes, granulomatosas e neoplásicas. Os autores apresentam o caso clínico de um doente com imunodeficiência comum variável manifestada por infeções cutâneas de repetição e linfadenite recorrente. Este caso tem como objetivo alertar para os aspetos clínicos desta imunodeficiência, a fim de permitir seu diagnóstico precoce, evitando-se prognósticos desfavoráveis.(AU)

Common variable immunodeficiency is a primary immunodeficiency with a heterogeneous presentation, characterized by decreased immunoglobulin levels. It is characterized by recurrent infections, predisposition to autoimmune, granulomatous and neoplastic diseases. The authors report a case of a patient with common variable immunodeficiency and history of skin infections and recurrent lymphadenitis. This case report aims to draw the attention to the clinical aspects of this immunodeficiency, in order to promote an early diagnosis, avoiding poor outcomes.(AU)

Clinical Manifestations and Treatment in Korean Patients with X-Linked Agammaglobulinemia

PURPOSE: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by mutations in the Bruton's tyrosine kinase (Btk) gene. The aim of this study was to investigate the clinical manifestations, molecular features, and treatment status of XLA in Korean patients at Seoul National University Children's Hospital. METHODS: Fourteen Korean boys with XLA showing serum agammaglobulinemia, non-detectable to less than 2% of peripheral B-cells, and mutation of the Btk gene were enrolled. We observed the clinical features, laboratory findings, status of treatment, and complications in these XLA patients. RESULTS: All XLA patients had a history of recurrent bacterial infections before diagnosis, and 20% of them had a neutropenia. Of the XLA patients 35.7% had a family history of XLA and 75% of their mothers were carriers. Btk gene analysis showed variable gene mutations in Xq22 including 9 amino acid substitutions, 3 frameshifts, 1 premature stop codon, and 1 splice defect. After intravenous immunoglobulin replacement therapy, infection episodes decreased, but complications such as bronchiectasis and chronic sinusitis remained. CONCLUSIONS: In patients less than 4 years of age with recurrent infection, analysis of serum gamma globulin levels and the Btk gene are recommended for the early diagnosis of XLA and for the appropriate prevention of recurrent infection.

Clinical Manifestations and Treatment in Korean Patients with X-Linked Agammaglobulinemia

PURPOSE: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency caused by mutations in the Bruton's tyrosine kinase (Btk) gene. The aim of this study was to investigate the clinical manifestations, molecular features, and treatment status of XLA in Korean patients at Seoul National University Children's Hospital. METHODS: Fourteen Korean boys with XLA showing serum agammaglobulinemia, non-detectable to less than 2% of peripheral B-cells, and mutation of the Btk gene were enrolled. We observed the clinical features, laboratory findings, status of treatment, and complications in these XLA patients. RESULTS: All XLA patients had a history of recurrent bacterial infections before diagnosis, and 20% of them had a neutropenia. Of the XLA patients 35.7% had a family history of XLA and 75% of their mothers were carriers. Btk gene analysis showed variable gene mutations in Xq22 including 9 amino acid substitutions, 3 frameshifts, 1 premature stop codon, and 1 splice defect. After intravenous immunoglobulin replacement therapy, infection episodes decreased, but complications such as bronchiectasis and chronic sinusitis remained. CONCLUSIONS: In patients less than 4 years of age with recurrent infection, analysis of serum gamma globulin levels and the Btk gene are recommended for the early diagnosis of XLA and for the appropriate prevention of recurrent infection.

Pyoderma Gangrenosum in a Patient with X-Linked Agammaglobulinemia

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disorder caused by germline mutations of B-cell tyrosine kinase (BTK) gene. It is characterized by decreased serum immunoglobulins levels and circulating mature B cells. This defect in humoral immunity leads to increased susceptibility to infection. Pyoderma gangrenosum (PG) is an uncommon, ulcerating, neutrophilic dermatosis. Here we report PG in an 8-year-old patient with XLA. The patient received intravenous immunoglobulin treatment in conjunction with prednisone and topical application of 0.03% tacrolimus ointment and the ulcer was almost completely healed in the 2 weeks of follow-up. The coexistence has been rarely reported. XLA may be a possible cofactor in the pathogenesis of PG.

Agammaglobulinemia ligada al cromosoma X en adultos: Evolucion clínica / X-linked agammaglobulinemia in adults. Clinical evolution

La agammaglobulinemia ligada al cromosoma X (XLA) se caracteriza por la ausencia o reducción significativa de linfocitos B, niveles bajos o indetectables de inmunoglobulinas y, clínicamente, por infecciones principalmente respiratorias por bacterias capsuladas extracelulares y diarrea recurrente. El tratamiento de reemplazo con gammaglobulina ha permitido a la mayor parte de los enfermos llegar a adultos con una buena calidad de vida. Analizamos las características clínicas de 14 pacientes mayores de 18 años con diagnóstico de XLA asistidos en nuestra Unidad desde 2003, fecha en que fue derivado el primer paciente, hasta 2015. La edad promedio en el momento de la derivación fue de 20.4 años, en el momento de la última consulta de 25.5. El tiempo promedio de seguimiento fue de 59.8 meses. Previo al diagnóstico todos habían presentado infecciones, las más frecuentes fueron las respiratorias. Posteriormente al diagnóstico todos iniciaron tratamiento de reemplazo con gammaglobulina endovenosa, y a pesar de que las infecciones disminuyeron en frecuencia y gravedad, en este período se presentaron enfermedades con secuelas graves. Al comenzar el seguimiento en nuestra Unidad, 35.7% presentaban deterioro de la función respiratoria, solo grave en un paciente. Durante el seguimiento ninguno presentó deterioro de la función respiratoria ni complicaciones clínicas importantes. Tres pasaron a gammaglobulina subcutánea con buena tolerancia. El número de adultos con XLA es cada vez mayor, la mayoría llegan a la segunda década de la vida sin complicaciones graves y bajo tratamiento se mantienen libres de enfermedades infecciosas graves y de progresión de sus secuelas pulmonares.

X-linked agammaglobulinemia (XLA) is characterized by absent or severely reduced B cells, low or undetectable immunoglobulin levels and clinically by extracellular bacterial infections which mainly compromise the respiratory tract as well as recurrent diarrheas. The mainstay of treatment is gammaglobulin replacement therapy, which allows most patients to reach adulthood with high quality of life. We analyzed the clinical features of 14 patients over 18 years of age with XLA diagnosis that received treatment in our unit from the year 2003, the date the first patient was derived, until 2015. The average age at which patients were referred was 20.4 years old; age at the last consult was 25.5. The average follow-up time was 59.8 months. Previously to being diagnosed all patients had suffered infections, most frequently respiratory. After diagnosis all were started on intravenous gammaglobulin replacement treatment and in spite of infections being reduced in severity and frequency, there were cases of severe disease with long term sequelae. At the beginning of our follow-up 35.7% presented impaired respiratory function with only one case being severe. In no cases during this period did the respiratory function worsen, nor were there severe clinical complications. Three patients were switched to subcutaneous immunoglobulin treatment with good tolerance. The number of XLA cases is increasing, as most reach the second decade of life without serious complications and remain free of severe infectious disease and further impairment of their respiratory functions with the treatment.

A novel BTK gene mutation, c.82delC (p.Arg28 Alafs*5), in a Korean family with X-linked agammaglobulinemia / 소아과

X-linked agammaglobulinemia (XLA) is a hereditary humoral immunodeficiency that results from Bruton’s tyrosine kinase (BTK) gene mutations. These mutations cause defects in B-cell development, resulting in the virtual absence of these lymphocytes from the peripheral circulation. Consequently, this absence leads to a profound deficiency of lg all isotypes, and an increased susceptibility to encapsulated bacterial infections. A 15-month-old Korean boy presented with recurrent sinusitis and otitis media after 6 months of age, and had a family history of 2 maternal uncles with XLA. Laboratory tests revealed a profound deficiency of Ig isotypes, and a decreased count of CD19⁺ B cells in the peripheral circulation. Based on his family history and our laboratory test results, he was diagnosed with XLA. We performed BTK gene analysis of peripheral blood samples obtained from family members to confirm the diagnosis. Mutational analysis revealed a novel hemizygous frameshift mutation (c.82delC, p.Arg28Alafs*5), in the BTK gene. His mother and maternal grandmother were heterozygous carriers of this mutation and his two maternal uncles were hemizygous at the same position. After XLA diagnosis, intravenous immunoglobulin (400 mg/kg, monthly) treatment was initiated; recurrent sinusitis and otitis media were subsequently brought under control. To our knowledge, this is the first reported case of a Korean pedigree with a novel mutation in the BTK gene.