Artykuły w czasopismach na temat „Inborn errors of immunity”

Inborn Errors of Immunity (IEI) are a heterogeneous group of disorders characterized by a defect in the function of at least one, and often more, components of the immune system. The aim of this narrative review is to discuss the epidemiology, the pathogenesis and the correct management of tumours in patients with IEI. PubMed was used to search for all of the studies published over the last 20 years using the keywords: “inborn errors of immunity” or “primary immunodeficiency” and “cancer” or “tumour” or “malignancy”. Literature analysis showed that the overall risk for cancer in children with IEI ranges from 4 to 25%. Several factors, namely, age of the patient, viral infection status and IEI type can influence the development of different cancer types. The knowledge of a specific tumour risk in the presence of IEI highlights the importance of a synergistic effort by immunologists and oncologists in tracking down the potential development of cancer in known IEI patients, as well as an underlying IEI in patients with newly diagnosed cancers. In the current genomic era, the creation of an international registry of IEI cases integrated with malignancies occurrence information is fundamental to optimizing the diagnostic process and to evaluating the outcomes of new therapeutic options, with the hope to obtain a better prognosis for these patients.

The immune system's function is to protect against microorganisms, but infection is nonetheless the most frequent cause of death in human history. Until the last century, life expectancy was only ∼25 years. Recent increases in human life span primarily reflect the development of hygiene, vaccines, and anti-infectious drugs, rather than the adjustment of our immune system to coevolving microbes by natural selection. We argue here that most individuals retain a natural vulnerability to infectious diseases, reflecting a great diversity of inborn errors of immunity.

Introduction. Inborn errors of immunity include a broad spectrum of genetic diseases, in which a specific gene mutation might alter the entire emphasis and approach for an individual patient.Objective. To conduct a comprehensive analysis of the correlation between phenotypic and molecular diagnoses in patients with confirmed inborn errors of immunity at a tertiary hospital in Cali, Colombia.Materials and methods. We conducted a retrospective study in which we sequentially evaluated all available institutional medical records with a diagnosis of inborn errors of immunity.Results. In the Clinical Immunology Service of the Hospital Universitario del Valle, 517 patients were evaluated. According to the IUIS-2022 classification, 92 patients (17.35%) were definitively diagnosed with an inborn error of immunity. Of these, 38 patients underwent genetic studies. The most prevalent category was predominantly antibody deficiencies (group III) (38/92 - 41.3%). A broad spectrum of genetic defects, novel and previously reported, were described, including mutations in the following genes: ATM, BTK, ERBIN, MAB21L2, RAG2, SAVI, SH2D1A, STAT1, SYK, and TMEM173. Less frequent findings included cases of the WHIM syndrome, SYK gain-of-function, and IL-7 deficiency.Conclusions. The establishment of the Clinical Immunology Service in the Hospital Universitario del Valle has emerged as a pivotal resource, catering to individuals with limited financial means and covered by public health insurance within the southwest region of Colombia. Molecular genetics confirmatory diagnosis was achieved in 38 patients (41.3%) with inborn errors of immunity and changed the diagnosis in 24 cases (26%).

Background: Inborn errors of immunity originate from monogenic mutations that should be considered in the suggestive diagnosis of patients with recurrent or severe infections, allergies, autoimmunity, autoinflammatory diseases, bone marrow failure and malignancy. Case report: Pediatric patient, male, 4 years old, treated in the medical service for fever of 39°C, difficult to control. The simple chest x-ray reported left pulmonary consolidation. The infectious condition evolved into necrotizing pneumonia of the left upper lobe, so it was decided to perform a lobectomy. The diagnosis of some inborn error of immunity was suspected. The determination of serum immunoglobulins reported IgA below the reference values. At 4 years he continued to have decreased serum IgA (5.5 mg/dL). Conclusion: The diagnosis of selective IgA deficiency is established after 4 years of life; However, due to the patient’s severe infection, addressing some inborn error of immunity had to be implemented. Keywords: Recurrent infections; Inborn error of immunity; Necrotizing pneumonia; Lobectomy; IgA; Selective IgA deficiency.

Objective: To evaluate the association between the expanded lymphoid profile and inborn errors of immunity using flow cytometry. Methods: Observational and cross-sectional, case-control study, carried out in patients with a diagnosis or clinical suspicion of inborn errors of immunity, treated at the Santísima Trinidad Children’s Hospital in Córdoba, Argentina, from August 2021 to November 2022. Clinical data were collected, and peripheral blood samples were obtained for flow cytometry analysis, using the PIDOT tube, to identify lymphocyte subpopulations. For statistical analysis, Fisher’s exact test, odds ratio and binary logistic regression model were used. Results: 40 cases and 20 controls were analyzed. The most frequently altered lymphocyte subpopulations were: CD4+ n (63%), Mem c/s (60%) and Mem s/s (55%). A statistically significant association was found between several lymphocyte subpopulations and health-disease status. Binary logistic regression reported Mem s/s and CD4+n as altered lymphocyte subpopulations with a greater probability to have inborn errors of immunity. Conclusion: This study contributes to improving the understanding of inborn errors of immunity and demonstrates a strong association with altered lymphocyte subpopulation profiles. Mem s/s and CD4+n emerge as relevant biomarkers for diagnosis. Heterogeneity in different diseases and in flow cytometry underlines the importance of evaluating each patient individually, to improve diagnosis and treatment. Keywords: Inborn errors of immunity; Flow cytometry; Lymphocyte subpopulations; Diagnostic markers.

The epigenome bridges environmental factors and the genome, fine-tuning the process of gene transcription. Physiological programs, including the development, maturation and maintenance of cellular identity and function, are modulated by intricate epigenetic changes that encompass DNA methylation, chromatin remodeling, histone modifications and RNA processing. The collection of genome-wide DNA methylation data has recently shed new light into the potential contribution of epigenetics in pathophysiology, particularly in the field of immune system and host defense. The study of patients carrying mutations in genes encoding for molecules involved in the epigenetic machinery has allowed the identification and better characterization of environment-genome interactions via epigenetics as well as paving the way for the development of new potential therapeutic options. In this review, we summarize current knowledge of the role of epigenetic modifications in the immune system and outline their potential involvement in the pathogenesis of inborn errors of immunity.

Inborn errors of immunity are genetic defects of the immune system, causing increased susceptibility to infection, autoinflammation, autoimmunity and immune dysregulation. Next-generation sequencing has enabled exponential identification of novel inborn errors of immunity due to mutations in genes encoding for proteins that participate in the immune response. However, genomic sequencing often yields multiple variants in potential candidate genes, hence functional validation of these genetic defects becomes paramount to achieve diagnosis and discovery. Genome-editing technologies such as CRISPR-Cas9 have allowed exponential advances on discovery of new primary immunodeficiencies, enabling appropriate diagnosis and treatment. This review summarizes the heterogeneous clinical presentation of primary immunodeficiencies and contextualizes the rationale for functional validation studies to achieve diagnosis and discovery, subsequently leading to the application of directed therapies.

AbstractThe most recent updated classification of inborn errors of immunity/primary immunodeficiencies, compiled by the International Union of Immunological Societies Expert Committee, was published in January 2020. Within days of completing this report, it was already out of date, evidenced by the frequent publication of genetic variants proposed to cause novel inborn errors of immunity. As the next formal report from the IUIS Expert Committee will not be published until 2022, we felt it important to provide the community with a brief update of recent contributions to the field of inborn errors of immunity. Herein, we highlight studies that have identified 26 additional monogenic gene defects that reach the threshold to represent novel causes of immune defects.

Inborn errors of immunity are a heterogeneous group of genetically determined disorders that compromise the immune system, predisposing patients to infections, autoinflammatory/autoimmunity syndromes, atopy/allergies, lymphoproliferative disorders, and/or malignancies. An emerging manifestation is susceptibility to fungal disease, caused by yeasts or moulds, in a superficial or invasive fashion. In this review, we describe recent advances in the field of inborn errors of immunity associated with increased susceptibility to fungal disease.

After infections, malignancies, lymphomas especially, are the second most frequent cause of death in patients with inborn errors of immunity. Factors predetermining the appearance and aggressiveness of lymphomas include gene defects, defects of immune surveillance and regulation as well as infections with oncogenic viruses. Aggressive non-Hodgkin lymphomas, mostly diffuse large B-cell and Bukit subtypes are predominant in deoxyribonucleic acid repair defects, while Hodgkin lymphoma becomes equally present in patients with defects of immune regulation. Marginal zone and mucosa-associated lymphoid tissue lymphomas, appear to be frequent in defects of antibody production, especially in patients with common variable immune deficiency. The prevalence of Epstein-Barr virus may vary within entities, but there is no entity without at least a few cases of lymphoma and Epstein-Barr virus co-infection. Standard treatment of lymphomas associated with deoxyribonucleic acid repair defects and severe combined deficiencies, is stem cell transplantation. Lymphomas in inborn errors of immunity with a less severe clinical presentation, should be treated with immunochemotherapy and monoclonal antibodies (Brentuximab, Rituximab) wherever feasible. There is no data about the usefulness of checkpoint inhibitors, bi-specific antibodies and T-cells with chimeric antigen receptor. Allogeneic stem cell transplantation represents a major indication for treatment of relapse/refractory lymphomas in any inborn error of immunity. Potential benefit of therapy with Chimeric antigen receptor Natural-killer cells in lymphomas associated with inborn errors of immunity, remains to be seen in future studies.

Current gene therapy for inborn errors of immunity have involved the use of gene addition approaches with viral delivery. This main strategy has had demonstrated success mainly in severe combined immune deficiency, Wiskott-Aldrich syndrome, and chronic granulomatous disease. Despite the increasing success of gene therapy, there are limitations of gene therapy, and, therefore, hematopoietic stem cell transplantation continues to be the preferred option. With improvements in viral delivery through next-generation lentiviral vectors and the advent of gene editing with CRISPR-Cas9, the efficacy and safety of gene therapy may soon surpass hematopoietic stem cell transplantation. Furthermore, these advances improve the viability of gene therapy for inborn errors of immunity primarily through decreased risk of transplantation-related complications. Therefore, despite current limitations, gene therapy for inborn errors of immunity is poised to continue to expand to more patients and indications.

Objectives Inborn errors of immunity (IEI) are prevalent in tribal cultures due to frequent consanguineous marriages. Many of these disorders are autosomal recessive, resulting from founder mutations; hence they are amenable to prevention. The primary objective of this study was to evaluate the pathogenicity of novel variants of IEI found among Emiratis. Methods This retrospective data collection study reports novel variants of IEI detected by diagnostic exome sequencing. Pathogenicity prediction was based on scoring tools, amino acid alignment, and Jensen–Shannon divergence values. Results Twenty-one novel variants were identified; nine were frameshift, three nonsense, four intronic (one pathogenic), and five missense (two pathogenic). Fifteen variants were likely pathogenic, of which 13 were autosomal recessive and two uncertain inheritance. Their clinical spectra included combined immunodeficiency, antibody deficiency, immune dysregulation, defects in intrinsic/innate immunity, and bone marrow failure. Conclusion The described novel pathogenic variants are core to a planned national screening program that aims toward IEI prevention. Future studies, however, are needed to confirm their natural history in individual patients and estimate their prevalence in the community.

Inborn errors of immunity (IEI) are inherited disorders that lead to defects in the development and/or function of the immune system. The number of disorders that can be treated by haematopoietic stem-cell transplantation (HSCT) has increased rapidly with the advent of next-generation sequencing. The methods used to transplant children with IEI have improved dramatically over the last 20 years. The introduction of reduced-toxicity conditioning is an important factor in the improved outcome of HSCT. Treosulfan has myeloablative and immunosuppressive properties, enabling engraftment with less toxicity than traditionally used doses of busulfan. It is firmly incorporated into the conditioning guidelines of the Inborn Errors Working Party of the European Society for Blood and Marrow Transplantation. Unlike busulfan, pharmacokinetically guided dosing of treosulfan is not part of routine practice, but data are emerging which indicate that further improvements in outcome may be possible, particularly in infants who have a decreased clearance of treosulfan. It is likely that individualized dosing, not just of treosulfan, but of all agents used in conditioning regimens, will be developed and implemented in the future. This will lead to a reduction in unwanted variability in drug exposure, leading to more predictable and adjustable exposure, and improved outcome of HSCT, with fewer late adverse effects and improved quality of life. Such conditioning regimens can be used as the basis to study the need for additional agents in certain disorders which are difficult to engraft or require high levels of donor chimerism, the dosing of individual cellular components within grafts, and effects of adjuvant cellular or immunotherapy post-transplant. This review documents the establishment of treosulfan worldwide, as a safe and effective agent for conditioning children with IEI prior to HSCT.

Molecular, cellular, and clinical studies of human inborn errors of immunity have revolutionized our understanding of their pathogenesis, considerably broadened their spectrum of immunological and clinical phenotypes, and enabled successful targeted therapeutic interventions. These studies have also been of great scientific merit, challenging a number of immunological notions initially established in inbred mice while revealing previously unrecognized mechanisms of host defense by leukocytes and other cells and of both innate and adaptive tolerance to self.

Inborn errors of immunity (IEI) are disorders mostly caused by mutations in genes involved in host defense and immune regulation. Different degrees of gastrointestinal (GI) involvement have been described in IEI, and for some IEI the GI manifestations represent the main and characteristic clinical feature. IEI also carry an increased risk for atopic manifestations. Eosinophilic gastrointestinal diseases (EGIDs) are emerging disorders characterized by a chronic/remittent and prevalent eosinophilic inflammation affecting the GI tract from the esophagus to the anus in the absence of secondary causes of intestinal eosinophilia. Data from the U.S. Immunodeficiency Network (USIDNET) reported that EGIDs are more commonly found in patients with IEI. Considering this element, it is reasonable to highlight the importance of an accurate differential diagnosis in patients with IEI associated with mucosal eosinophilia to avoid potential misdiagnosis. For this reason, we provide a potential algorithm to suspect an EGID in patients with IEI or an IEI in individuals with a diagnosis of primary EGID. The early diagnosis and detection of suspicious symptoms of both conditions are fundamental to prevent clinically relevant complications.

The technological advances in diagnostics and therapy of primary immunodeficiency are progressing at a fast pace. This review examines recent developments in the field of inborn errors of immunity, from their definition to their treatment. We will summarize the challenges posed by the growth of next-generation sequencing in the clinical setting, touch briefly on the expansion of the concept of inborn errors of immunity beyond the classic immune system realm, and finally review current developments in targeted therapies, stem cell transplantation, and gene therapy.

The immune system protects the body. When defenses are compromised, people with hereditary immunological disorders become vulnerable to many life-threatening infections. Inborn errors of immunity (primary immunodeficiencies), manifested in patients in increased susceptibility to infectious diseases, autoimmune diseases, allergies, and malignant neoplasms. Today, this group of diseases is still considered quite rare. However, the development of diagnostic technologies expands the list of nosologies associated with inborn errors of immunity. Neonatal screening for inborn errors of immunity could solve many of the problems of these patients, but the procedure is not carried out in the Russian Federation. Therefore, diagnostics based on an analysis of the clinical manifestations of diseases. In most cases, the disease is diagnosed in early childhood. Here, the role of both the parents of the child-patient and the medical staff is important. The health and life of the child depends on their awareness of the disease, methods of diagnosis, treatment. This group of diseases is chronic, under an hour, severe. In the absence of timely diagnosis and proper therapy, it can be fatal. The article describes the experience of applied quantitative research conducted by the method of questioning patients with primary immunodeficiencies (parents of underage patients), about their disease, methods of treatment, problems arising in the long-term struggle with this complex disease. The author notes that patients and primary care doctors or general practitioners are poorly informed about diseases associated with primary immunodeficiencies. It is concluded that it is necessary to increase the informational medical culture of the population, especially the young, as participants in the interaction "doctor-patient" and representatives of the interests of minor children-patients with inborn errors of immunity.

Inborn errors of immunity are monogenic disorders that predispose patients to immune dysregulation, autoimmunity, and infection. Some autoimmune diseases, such as autoimmune cytopenias, systemic lupus erythematosus, and inflammatory bowel diseases, are increasingly recognized as phenotypes of inborn errors of immunity.The objective of this article was to identify red flags or clinical/laboratory markers to suspect inborn errors of immunity in patients with autoimmune cytopenias, systemic lupus erythematosus, and inflammatory bowel diseases through a systematic literature review.The study followed the systematic reviews and meta-analysis guidelines (PRISMA). After selection, we included 36 articles, and their methodological quality was verified using the Joanna Briggs Institute tools for individual risk of bias analysis.The principal red flags in autoimmune cytopenias are chronic, recurrent, and refractory cytopenias, recurrent infection, severe infectious complications associated with immunosuppressive treatment, and chronic lymphoproliferation. In systemic lupus erythematosus, red flags include age of onset before five years, severe organ involvement, chilblain lesions, and chronic lymphoproliferation. For inflammatory bowel diseases, red flags are an age of onset before two years, resistance to conventional therapies, atypical endoscopic or histologic findings, and consanguineous parents. Autoimmune diseases may be the primary manifestation of inborn errors of immunity in pediatric and adult patients. An early diagnosis of a monogenic disorder allows for the tailoring of effective treatment plans, providing prognostic information to families, and offering genetic counseling.

Abstract We report the updated classification of Inborn Errors of Immunity/Primary Immunodeficiencies, compiled by the International Union of Immunological Societies Expert Committee. This report documents the key clinical and laboratory features of 430 inborn errors of immunity, including 64 gene defects that have either been discovered in the past 2 years since the previous update (published January 2018) or were characterized earlier but have since been confirmed or expanded upon in subsequent studies. The application of next-generation sequencing continues to expedite the rapid identification of novel gene defects, rare or common; broaden the immunological and clinical phenotypes of conditions arising from known gene defects and even known variants; and implement gene-specific therapies. These advances are contributing to greater understanding of the molecular, cellular, and immunological mechanisms of disease, thereby enhancing immunological knowledge while improving the management of patients and their families. This report serves as a valuable resource for the molecular diagnosis of individuals with heritable immunological disorders and also for the scientific dissection of cellular and molecular mechanisms underlying inborn errors of immunity and related human diseases.

Introduction. Inborn errors of immunity is a diverse group of rare diseases caused by over 400 genetic mutations affecting the immune system and increasing infection susceptibility, autoimmunity, and malignancy. Hematopoietic stem cell transplantation offers a curative option for some inborn errors of immunity, with haploidentical donors providing a viable alternative when identical donors are unavailable.Objective. To determine survival, usefulness of weekly chimerism monitoring, immune reconstitution, and complications in patients with inborn errors of immunity who underwent haploidentical hematopoietic stem cell transplantation at a reference center in Colombia.Materials and methods. We conducted a retrospective and observational study of a case series of pediatric patients who underwent haploidentical hematopoietic stemcell transplantation with post-transplant cyclophosphamide and follow-up with weekly chimerism. Survival analysis was performed using the Kaplan-Meier method.Results. Sixteen patients with haploidentical familial donor transplantation were included. The most frequent diagnosis was severe combined immunodeficiency (n=5). Eleven out of seventeen patients received a non-myeloablative conditioning regimen. Twelve out of sixteen patients developed acute graft-versus-host disease. Out of these, 3 corresponded to grades III-IV. Post-transplant infections affected 14 of the subjects, predominating bacterial agents. Median T-cell chimerism was greater than 80% during the follow-up. Reconstitution of B and T lymphocytes was achieved in more than 80%. Overall survival at five years was 81%. Survival at 100 days was 94%.Conclusion. Haploidentical hematopoietic stem cell transplantation using post-transplant cyclophosphamide is a viable alternative for inborn errors of immunity when an identical donor is unavailable. Serial chimerism monitoring is useful for graft follow-up.

Inborn errors of immunity (IEI) are a group of disorders that are mostly caused by genetic mutations affecting immune host defense and immune regulation. Although IEI present with a wide spectrum of clinical features, in about one third of them various degrees of gastrointestinal (GI) involvement have been described and for some IEI the GI manifestations represent the main and peculiar clinical feature. The microbiome plays critical roles in the education and function of the host’s innate and adaptive immune system, and imbalances in microbiota-immunity interactions can contribute to intestinal pathogenesis. Microbial dysbiosis combined to the impairment of immunosurveillance and immune dysfunction in IEI, may favor mucosal permeability and lead to inflammation. Here we review how immune homeostasis between commensals and the host is established in the gut, and how these mechanisms can be disrupted in the context of primary immunodeficiencies. Additionally, we highlight key aspects of the first studies on gut microbiome in patients affected by IEI and discuss how gut microbiome could be harnessed as a therapeutic approach in these diseases.

Inborn errors of immunity (IEI) also referred to as primary immunodeficiencies, are a heterogeneous group of rare genetic disorders affecting the immune system. IEI may present as increased susceptibility to infectious diseases, autoimmunity, autoinflammatory and malignant diseases. There are currently more than 400 different genes identified that may cause IEI.1 Hematopoietic Stem Cell Transplantation (HSCT) can correct the immune defect of several of these diseases and is currently considered the treatment of choice for some severe forms of IEI.2 In Brazil, the first transplant performed for a patient with IEI was in 1990, at the National Cancer Institute in Rio de Janeiro. It was a patient with Chediak-Higashi Syndrome that was transplanted after diagnosing a Lymphoma. The first report of Brazilian experience of HSCT for PID was published in 2018 and included data from transplants in 221 patients transplanted from July 1990 to December 2015 in 11 centers which participated in the Brazilian collaborative group.3 Transplants in patients with IEI are highly complex and should be performed in centers with continuous and significant experience in these procedures and that participate in collaborative studies. In these rare disorders, single-center reports of small cohorts are of limited value. For that reason, both Europe (IEWP/EBMT (Inborn Errors Working Party/European Group for Blood and Marrow Transplantation) and USA (PIDTC (Primary Immune Deficiency Treatment Consortium) formed collaborative groups to study outcomes of HSCT in PID and elaborate protocols to standardize treatment in participating institutions. The Brazilian Pediatric study group on HSCT strongly recommends that centers transplanting patients with IEI should collaborate with international groups and follow the joint EBMT/ESID Inborn Errors Working Party guidelines.4 We also recommend that international treatment protocols should be adapted taking into consideration patients’ performance status and particularities found in our country (BCG vaccination, socio-demographic characteristics). The main IEIs that can be treated with HSCT are described in the Table 1. Severe Combined Immunodeficiency (SCID): Severe combined immunodeficiencies (SCID) are a group of rare, monogenic diseases that are characterized by a block in the development of T lymphocytes. Typical SCID are characterized by the absence of T lymphocytes and deficient T-lymphocyte proliferation. Lymphocyte immunophenotyping show different patterns considering the presence of B and/or NK cells, that are generally correlated with the causative genetic defect. There are currently more than 14 different genes that were described causing SCID, the most frequent being: IL2RG, JAK3 (T-B+NK-); RAG 1/2, DCLRE1C (T-B-NK+); ADA (T-B-NK-); IL7RA (T-B+NK+). HSCT is the only stablished curative therapy for patients with SCID. More recently, Gene therapy is appearing as a very promising alternative treatment and potentially may substitute HSCT as a standard of care for these patients, but as of today only one therapy has been commercially licensed by the European Medicines Agency (Strimvelis®) for ADA SCID. Clinical studies are ongoing for other genetic defects. 5-7 Patients with SCID are considered a pediatric emergency. HSCT must be performed as soon as possible with the more rapidly and best available donor. A matched related sibling that is not affected by the disease is the gold standard. If not available, alternative donors (matched unrelated bone marrow or umbilical cord blood donors) may be considered as long as they are readily available.8 Haploidentical family donors have been used since the late 80s, but the larger experience with this type of donor comes from studies with in vitro T-cell depletion (former CD34+ selection and currently CD3alfa/beta/CD19 depletion). This techniques are very expensive and not easily available in our country. The use of haploidentical donors with post-transplant cyclophosphamide (haplo-PTCy) is a more accessible alternative and its use in patients with SCID have been done in series of case. The larger experience in haplo-PTCy was published by the Brazilian group. In this study there were 34 patients with SCID that received a haplo-PTCy. These transplants should preferably be performed in centers with experience due to their high complexity. 9 Patients with SCID are profoundly susceptible to opportunistic infections and live vaccines are contraindicated. The Bacille Calmette Guerin (BCG) vaccine in these patients can promote disseminated infection by the vaccine strain and is associated with numerous complications, with increased rates of morbidity and mortality. If the patient has received BCG before diagnosis, prophylaxis with one or two drugs is recommended. For patients presenting with local or disseminated BCGosis, four or more drugs may be necessary for treatment.10 Also the rotavirus vaccine may cause bloody diarrhea sometimes mimicking Cow's milk protein allergy. Patients with SCID present with life-threatening infections (viral, fungal, bacterial) within the first year of life. HSCT success rates are highly correlated to the early diagnosis and the presence of infections at the time of transplant.11 For that reason, neonatal screening (measurement of T cell receptor excision circles levels) is encouraged and being implemented in different countries. In Brazil, a few pilot studies have been performed and currently the state of Minas Gerais and the city of São Paulo have started the screening program.12 Reference to a specialized center as soon as the diagnosis have been made is crucial, immunoglobulin (IVIg) replacement therapy and PJP prophylaxis must be started promptly and active infections need to be aggressively treated. Blood products need to be irradiated and leukodepleted before transfusion to avoid GVHD and CMV infection. Breast-feeding from a CMV positive mother should be discouraged. Access to a specialist, although essential, should not delay the immediate start of IVIg replacement and antimicrobial prophylaxis. SCID phenotype (presence of B and/or NK cells) and genetic defect (if available) are important in deciding which conditioning regimen to use. Although the most important outcome is developing a functional T-cell compartment, some degree of myeloid chimerism may help B-cell reconstitution and long-term thymic output. In addition, choice of the intensity of conditioning regimen may take into account the clinical and performance status of patients. In particular cases, HSCT can be performed without conditioning (T-B+NK- SCID, with matched sibling donor). In this situation only T cells from the donor will develop, while the myeloid compartment remains from the patient leading to a split chimerism. Some patients may not develop B-cell function, requiring lifelong IVIg replacement therapy. The majority of patients will need some conditioning and most indicated regimen include reduced dose of busulfan (pharmacokinetics is recommended – AUC 60–70 mg*h/L), associated with fludarabine +/- serotherapy (thymoglobulin or alemtuzumab) considering donor type. 4,13 Patients with ADA-deficiency are a particular type of SCID. Internationally there are other options of treatment besides HSCT, including enzyme replacement therapy and Gene Therapy.7 As these alternatives are not currently available in our country, HSCT remains the treatment of choice. For babies with SCID diagnosed by neonatal screening, as there is limited experience in newborns with regard to toxicity and tolerance of drugs used for conditioning, conditioned HSCT is not recommended before 6 to 8 weeks of age.4 Wiskott-Aldrich Syndrome HSCT is the main curative alternative, correcting the underlying immunodeficiency and thrombocytopenia. The outcome of transplantation in experienced centers is around 80-90% survival using related donors, voluntary bone marrow donors, umbilical cord blood or haploidentical donors. The most recommended conditioning regimen is myeloablative and the degree of donor chimerism, particular in the myeloid compartment, is associated with better results, especially related to correction of thrombocytopenia and autoimmunity. HSCT outcomes are more favorable in patients under 5 years of age and with fully matched donors.14,15 Hemophagocytic syndromes Familial Haemophagocytic lymphohistiocytosis (FHLH) is a clinical hyperinflammatory syndrome associated with an uncontrolled immune response, resulting in a cytokine storm caused by a primary immune defect. Several mutations have been described as causes of FHLH (PRF1, UNC13D, STX11, STXBP2) and other genetic syndromes can also have a clinical presentation similar to HLH (Chediak-Higashi Syndrome, Griscelli type II, XLP). Up to 20% of primary HLH may have no known genetic mutation. Initial treatment includes chemotherapy and immunosuppressants (recommended protocol HLH-2004), or antibody-based therapy (thymoglobuline, alemtuzumab) until acute symptoms are controlled. HSCT is the treatment of choice for primary HLH and may be performed with the best available donor. Best results are reported when patients have no active HLH at the time of transplant. Choice of conditioning regimen may take into account the type of donor, clinical status of the patient and disease control. Reduced toxicity regimens are recommended including bussulfan (with pharmacokinetics), fludarabine and serotherapy; or fludarabine and melphalan. The high incidence of failure of engraftment and mixed chimerism requiring further intervention must be taken into consideration when using regimens with melphalan. Stable mixed chimerism (some reports say >30%) may be sufficient to protect against disease relapse.4,16-20 Chronic granulomatous disease HSCT is the only established curative therapy for chronic granulomatous disease (CGD). Recent studies show excellent survival particular in younger patients, using reduced toxicity regimens, and matched donors. Preferred donors are matched sibling donor or a well matched unrelated donor. Carrier family donors should be avoided, but in the absence of other suitable donors, female carriers may be considered after functional analysis (DHR). The use of alternative donors is still associated with inferior results and HSCT should be performed in experienced centers. Reduced toxicity conditioning based on busulfan (with pharmacokinetics), fludarabine and serotherapy (thymoglobuline or alemtuzumab) is recommended. Also, conditionings based on treosulfan show excellent results, but this drug is not available in our country. Stable mixed chimerism may be sufficient to protect against infections. Patients with inflammatory symptoms (specially colitis) may need immunosuppressive treatment before HSCT to control symptoms, as inflammation may increase risk of graft failure and GVHD. 4,21,22 Primary Immune Regulatory Disorders (PIRD) Primary Immune Regulatory Disorders (PIRD) are an expanding group of diseases caused by gene defects in several different immune pathways, such as regulatory T cell function. There is a growing number of recent reports showing that some PIRD may benefit from HSCT. These include diseases such as IPEX syndrome, CTLA4 deficiency, LRBA and immune dysregulation with colitis (very early onset inflammatory bowel disease with genetic defect – IL10, IL10R). Patients with PIRD develop clinical manifestations associated with diminished and exaggerated immune responses and disease symptoms control is important to HSCT success. Targeted biological agents such as abatacept are increasingly available and can result in significant reduction in disease activity. Except for IPEX syndrome, that a large multicenter study showed advantage in overall survival and quality of life in transplanted patients compared to those treated with immunosuppression, these diseases are rare and only few series of cases treated with HSCT have been reported in the literature. For this reason, no general recommendations may be done at this point regarding transplant indication and treatment regimens. Therefore, we recommend that these patients be referred to specialized reference centers and discussed in an expert panel. 23-25

Purpose of review The purpose of this focused review is to discuss unusual presentations of viral infections in the context of specific inborn errors of immunity. We will discuss hyper immunoglobulin E (IgE) syndromes, epidermodysplasia verruciformis, and X-linked agammaglobulinemia as examples of inborn errors of immunity associated with specific presentations of viral infection and disease. Recent findings Advances in both genetic and viral diagnostics have broadened our understanding of viral pathogenesis in the setting of immune dysfunction and the variable phenotype of inborn errors of immunity. Dedicator of cytokinesis 8 (DOCK8) deficiency is now recognized as an inborn error of immunity within the hyper IgE syndrome phenotype and is associated with unusually aggressive cutaneous disease caused by herpes simplex and other viruses. Studies of patients with epidermodysplasia verruciformis have proven that rarely detected human papillomavirus subtypes may cause malignancy in the absence of adequate host defenses. Finally, patients with X-linked agammaglobulinemia may remain at risk for severe and chronic viral infections, even as immune globulin supplementation reduces the risk of bacterial infection. Summary Susceptibility to viral infections in patients with inborn errors of immunity is conferred by specific, molecular defects. Recurrent, severe, or otherwise unusual presentations of viral disease should prompt investigation for an underlying genetic defect.