[Recommendations about immunizations in patients with inborn errors of immunity]. / Recomendaciones para la inmunización de pacientes con errores innatos de la inmunidad.

Inborn errors of immunity (IEI) are a heterogeneous group of hereditary disorders that affect in number and/or function different components of the immune system, resulting in an increased risk and severity of infections, autoimmune diseases, allergic manifestations, autoinflammation and malignancy. Inactivated vaccines are generally safe in these patients, but may be ineffective in some cases, due to difference in immunogenicity. However, live viral and bacterial vaccines may lead to disease, with high morbidity and mortality, so it is essential a previous immunological work-out. In this document, the Pediatric Immunology Work Group of the Sociedad Argentina de Pediatría summarizes recommendations about immunizations in patients with IEI, their household contacts, as well as in patients under immunosuppressive treatment and hematopoietic stem cell transplant recipients.

Los errores innatos de la inmunidad (EII) constituyen un grupo heterogéneo de enfermedades hereditarias que afectan el número y/o la función de los distintos componentes del sistema inmune, lo que predispone a un incremento de la tasa y gravedad de infecciones, enfermedades autoinmunes, manifestaciones alérgicas, autoinflamación y malignidad. En estos pacientes, la inmunización con vacunas inactivadas es generalmente segura, pero puede no ser efectiva en determinados grupos de EII, sin generar el efecto protector deseado. La aplicación de vacunas vivas atenuadas (virales y bacterianas) puede llevar al desarrollo de enfermedad asociada a la inmunización, con elevada morbimortalidad, por lo que amerita previamente consultar al especialista. El presente informe resume las conclusiones del Grupo de Trabajo de Inmunología de la Sociedad Argentina de Pediatría respecto a la vacunación en pacientes con EII y sus convivientes, en pacientes bajo inmunosupresión farmacológica y en receptores de trasplante de células precursoras hematopoyéticas.

A Clinical Neurological Approach to the Child With Adenosine Deaminase Deficiency.

BACKGROUND: Severe combined immunodeficiency secondary to adenosine deaminase deficiency is rare. The deficiency of this enzyme results in the accumulation of substrates in the tissues, including the brain. Clinical signs of neurological involvement may include seizures, neurodevelopmental disorders, hypotonia, and sensorineural hearing loss. Hematopoietic stem cell transplantation corrects the failure of the immune system but not the neurological involvement. OBJECTIVES: To describe the spectrum of neurological complications identified in a series of children with severe combined immunodeficiency due to adenosine deaminase deficiency. Additionally, we propose a neurological approach including electrophysiological, radiological, and neurocognitive studies to address this group of children in an efficient and timely manner. METHODS: A descriptive, observational, retro-, and prospective analysis of patients with a confirmed immunological diagnosis seen between 1996 and 2021 and referred to the Department of Neurology for neurological evaluation was conducted. RESULTS: Ten patients met the inclusion criteria. The median age at diagnosis was 4 months (range, 1-36 months). All patients had neurodevelopmental delay with hypotonia in six, language delay in three, sensorineural hearing loss in four, and spastic paraparesis in one patient. Two children developed an epileptic syndrome, consisting of generalized epilepsy in one and focal epilepsy in the other. Neuroimaging showed brain calcifications in the basal ganglia and/or centrum semiovale in four patients and enlarged subarachnoid spaces in two other patients. CONCLUSION: In this pediatric series, the rate of neurological involvement associated with abnormalities on neuroimaging was high. Although this involvement could be related to accumulation of adenosine metabolites in the central nervous system, the possibility of associated chronic infections should be ruled out. Given the neurological manifestations, it is important to involve the pediatric neurologist in the multidisciplinary follow-up team.

Cancer Prevalence in Children with Inborn Errors of Immunity: Report from a Single Institution.

BACKGROUND: Inborn Errors of Immunity (IEI) comprise several genetic anomalies that affect different components of the innate and adaptive responses, predisposing to infectious diseases, autoimmunity and malignancy. Different studies, mostly in adults, have reported a higher prevalence of cancer in IEI patients. However, in part due to the rarity of most of these IEI subtypes (classified in ten categories by the Primary Immunodeficiency Committee of the International Union of Immunological Societies), it is difficult to assess the risk in a large number of patients, especially during childhood. OBJECTIVE: To document the cancer prevalence in a pediatric cohort from a single referral institution, assessing their risk, together with the type of neoplasia within each IEI subgroup. METHOD: An extensive review of clinical records from 1989 to 2022 of IEI patients who at some point developed cancer before the age of sixteen. RESULTS: Of a total of 1642 patients with IEI diagnosis, 34 developed cancer before 16 years of age, showing a prevalence (2.1%) significantly higher than that of the general age matched population (0.22). Hematologic neoplasms (mostly lymphomas) were the most frequent malignancies. CONCLUSION: This study represents one of the few reports focused exclusively in pediatric IEI cases, describing not only the increased risk of developing malignancy compared with the age matched general population (a fact that must be taken into account by immunologists during follow-up) but also the association of the different neoplasms with particular IEI subtypes, thus disclosing the possible mechanisms involved.

Expanding spectrum, intrafamilial diversity, and therapeutic challenges from 15 patients with heterozygous CARD11-associated diseases: A single center experience.

CARD11-associated diseases are monogenic inborn errors of immunity involving immunodeficiency, predisposition to malignancy and immune dysregulation such as lymphoproliferation, inflammation, atopic and autoimmune manifestations. Defects in CARD11 can present as mutations that confer a complete or a partial loss of function (LOF) or contrarily, a gain of function (GOF) of the affected gene product. We report clinical characteristics, immunophenotypes and genotypes of 15 patients from our center presenting with CARD11-associated diseases. Index cases are pediatric patients followed in our immunology division who had access to next generation sequencing studies. Variant significance was defined by functional analysis in cultured cells transfected with a wild type and/or with mutated hCARD11 constructs. Cytoplasmic aggregation of CARD11 products was evaluated by immunofluorescence. Nine index patients with 9 unique heterozygous CARD11 variants were identified. At the time of the identification, 7 variants previously unreported required functional validation. Altogether, four variants showed a GOF effect as well a spontaneous aggregation in the cytoplasm, leading to B cell expansion with NF-κB and T cell anergy (BENTA) diagnosis. Additional four variants showing a LOF activity were considered as causative of CARD11-associated atopy with dominant interference of NF-kB signaling (CADINS). The remaining variant exhibited a neutral functional assay excluding its carrier from further analysis. Family segregation studies expanded to 15 individuals the number of patients presenting CARD11-associated disease. A thorough clinical, immunophenotypical, and therapeutic management evaluation was performed on these patients (5 BENTA and 10 CADINS). A remarkable variability of disease expression was clearly noted among BENTA as well as in CADINS patients, even within multiplex families. Identification of novel CARD11 variants required functional studies to validate their pathogenic activity. In our cohort BENTA phenotype exhibited a more severe and expanded clinical spectrum than previously reported, e.g., severe hematological and extra hematological autoimmunity and 3 fatal outcomes. The growing number of patients with dysmorphic facial features strengthen the inclusion of extra-immune characteristics as part of the CADINS spectrum. CARD11-associated diseases represent a challenging group of disorders from the diagnostic and therapeutic standpoint, especially BENTA cases that can undergo a more severe progression than previously described.