Clinical heterogeneity in families with multiple cases of inborn errors of immunity.

BACKGROUND: Inborn errors of immunity (IEI) are a diverse range of genetic immune system illnesses affecting the innate and/or adaptive immune systems. Variable expressivity and incomplete penetrance have been reported in IEI patients with similar clinical diagnoses or even the same genetic mutation. METHODS: Among all recorded patients in the national IEI registry, 193 families with multiple cases have been recognized. Clinical, laboratory and genetic variability were compared between 451 patients with different IEI entities. RESULTS: The diagnosis of the first children led to the earlier diagnosis, lower diagnostic delay, timely treatment and improved survival in the second children in the majority of IEI. The highest discordance in familial lymphoproliferation, autoimmunity and malignancy were respectively observed in STK4 deficiency, DNMT3B deficiency and ATM deficiency. Regarding immunological heterogeneity within a unique family with multiple cases of IEI, the highest discordance in CD3+, CD4+, CD19+, IgM and IgA levels was observed in syndromic combined immunodeficiencies (CID), while non-syndromic CID particularly severe combined immunodeficiency (SCID) manifested the highest discordance in IgG levels. Identification of the first ATM-deficient patient can lead to improved care and better survival in the next IEI children from the same family. CONCLUSION: Intrafamilial heterogeneity in immunological and/or clinical features could be observed in families with multiple cases of IEI indicating the indisputable role of appropriate treatment and preventive environmental factors besides specific gene mutations in the variable observed penetrance or expressivity of the disease. This also emphasizes the importance of implementing genetic evaluation in all members of a family with a history of IEI even if there is no suspicion of an underlying IEI as other factors besides the underlying genetic defects might cause a milder phenotype or delay in presentation of clinical features. Thus, affected patients could be timely diagnosed and treated, and their quality of life and survival would improve.

The Autoimmune Manifestations in Patients with Genetic Defects in the B Cell Development and Differentiation Stages.

PURPOSE: Primary B cell defects manifesting as predominantly antibody deficiencies result from variable inborn errors of the B cell lineage and their development, including impairments in early bone marrow development, class switch recombination (CSR), or terminal B cell differentiation. In this study, we aimed to investigate autoimmunity in monogenic patients with B cell development and differentiation defects. METHODS: Patients with known genetic defects in the B cell development and differentiation were recruited from the Iranian inborn errors of immunity registry. RESULTS: A total of 393 patients with a known genetic defect in the B cell development and differentiation (257 males; 65.4%) with a median age of 12 (6-20) years were enrolled in this study. After categorizing patients, 109 patients had intrinsic B cell defects. More than half of the patients had defects in one of the ATM (85 patients), BTK (76 patients), LRBA (34 patients), and DOCK8 (33 patients) genes. Fifteen patients (3.8%) showed autoimmune complications as their first manifestation. During the course of the disease, autoimmunity was reported in 81 (20.6%) patients at a median age of 4 (2-7) years, among which 65 patients had mixed intrinsic and extrinsic and 16 had intrinsic B cell defects. The comparison between patients with the mentioned four main gene defects showed that the patient group with LRBA defect had a significantly higher frequency of autoimmunity compared to those with other gene defects. Based on the B cell defect stage, 13% of patients with early B cell defect, 17% of patients with CSR defect, and 40% of patients who had terminal B cell defect presented at least one type of autoimmunity. CONCLUSION: Our results demonstrated that gene mutations involved in human B cell terminal stage development mainly LRBA gene defect have the highest association with autoimmunity.

Clinical and Immunologic Characteristics of Non-Hematologic Cancers in Patients with Inborn Errors of Immunity.

Inborn errors of immunity (IEI) are a heterogeneous group of inherited disorders, and almost 500 genes associated with these disorders have been identified. Defects in IEI genes lead to diverse clinical manifestations including increased susceptibility to recurrent or prolonged infections, immune dysregulation phenotypes (such as severe atopy, allergy, autoimmunity, and uncontrolled inflammation, lymphoproliferation), as well as predisposition to malignancies. Although the majority of IEI patients present hematologic cancers, the characteristics of other types of cancers are not well described in these groups of patients. By investigating 5384 IEI patients registered in the Iranian national registry the clinical and immunologic phenotypes of patients with non-hematologic cancers were compared with other malignant and non-malignant patients. Solid tumors were reported <20% of malignant IEI patients (n = 27/144 patients) and appeared to be very heterogeneous by type and localization as well as molecular defects (mainly due to DNA repair defect resulted from ATM deficiency). The correlation between the type of malignancy and survival status was remarkable as patients with non-hematologic cancers survive higher than IEI patients with hematologic cancers. Our findings showed that different types of malignancy could be associated with specific entities of IEI. Therefore, the education of physicians about the risk of malignancies in IEI is required for personalized treatment and appropriate management of patients.

How do nuclear factor kappa B (NF-κB)1 and NF-κB2 defects lead to the incidence of clinical and immunological manifestations of inborn errors of immunity?

INTRODUCTION: Genetic defects affect the manner of the immune system's development, activation, and function. Nuclear factor-kappa B subunit 1 (NF-κB1) and NF-κB2 are involved in different biological processes, and deficiency in these transcription factors may reveal clinical and immunological difficulties. AREAS COVERED: This review article gathers the most frequent clinical and immunological remarkable characteristics of NF-κB1 and NF-κB2 deficiencies. Afterward, an effort is made to describe the biological mechanism, which is likely to be the cause of these clinical and immunological abnormalities. EXPERT OPINION: The present review article has explained the mechanism of contributions of the NF-κB1 and NF-κB2 deficiency in revealing immunodeficiency symptoms, specifically immunological and clinical manifestations. These mechanisms demonstrate the importance of NF-κB1 and NF-κB2 signaling pathways for B and T cell development, activation, antibody production, and immunotolerance. The manifestation of a mutation can range from no symptoms to severe complications in a family.

NF-κB1 and NF-κB2 are the transcription factors that have an essential role in the development and function of the immune system. Several mutations in the NF-κBs could lead to inborn errors of immune manifestations.There are different reports of NF-κB mutations with various clinical and immunological manifestations, whereas the mechanisms behind the appearance of these have been less discussed. We collected frequent clinical and immunological manifestations from the literature and discussed the likely biological cause of their occurrence. Here we clarify the potential mechanism that defects in NF-κB1 and NF-κB2 signaling lead to inadequate B and T cells function, specifically, insufficient switched memory B cells and class-switched antibodies and autoimmunity. We also focused on the straight correlation between deficiencies in immune system responses caused by defects in NF-κB and susceptibility to recurrent infections and other clinical problems.Since our understanding of the mechanisms of signaling pathways such as NF-κB deficiencies from genetic mutations to clinical manifestations in PIDs is limited, further in vitro and animal model studies are necessary to assess these pathways' comprehensive roles in immunodeficiency more accurately. [Figure: see text].

Diversity of malignancies in patients with different types of inborn errors of immunity.

Genetic defects in the development, maturation, and/or function of the immune cells can lead to Inborn errors of immunity (IEI) which may predispose patients to malignancies. The overall risk for cancer in children with IEI ranges from 4 to 25% and the type of malignancy is highly dependent on the specific mutant gene underlying IEI. We investigated 3056 IEI patients registered in the Iranian national registry between the years 1999 and 2020 in this retrospective cohort study. The frequency of malignancy and its association with the type of IEI in these patients were evaluated. A total of 82 IEI patients with malignancy were enrolled in this study. Among them, predominantly lymphoma was the most common type of malignancy (67.1%), followed by leukemia (11%), and cancers of the head and neck (7.3%). Among identified lymphoma cancers, non-Hodgkin's lymphomas were the most frequent type (43.9%) followed by different subtypes of Hodgkin's lymphoma (23.2%). Solid tumors (18.3%) appeared to be very heterogeneous by type and localization. The correlation between the type of malignancy and survival status and the association between the type of malignancy and IEI entities were unremarkable. The awareness of the association between the presence of IEI and cancer highlights the importance of a synergistic effort by oncologists and immunologists in the early diagnosis of malignancy and personalized therapeutic strategies in IEI patients.

Genetic and immunologic evaluation of children with inborn errors of immunity and severe or critical COVID-19.

BACKGROUND: Most severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals are asymptomatic or only exhibit mild disease. In about 10% of cases, the infection leads to hypoxemic pneumonia, although it is much more rare in children. OBJECTIVE: We evaluated 31 young patients aged 0.5 to 19 years who had preexisting inborn errors of immunity (IEI) but lacked a molecular diagnosis and were later diagnosed with coronavirus disease 2019 (COVID-19) complications. METHODS: Genetic evaluation by whole-exome sequencing was performed in all patients. SARS-CoV-2-specific antibodies, autoantibodies against type I IFN (IFN-I), and inflammatory factors in plasma were measured. We also reviewed COVID-19 disease severity/outcome in reported IEI patients. RESULTS: A potential genetic cause of the IEI was identified in 28 patients (90.3%), including mutations that may affect IFN signaling, T- and B-cell function, the inflammasome, and the complement system. From tested patients 65.5% had detectable virus-specific antibodies, and 6.8% had autoantibodies neutralizing IFN-I. Five patients (16.1%) fulfilled the diagnostic criteria of multisystem inflammatory syndrome in children. Eleven patients (35.4%) died of COVID-19 complications. All together, at least 381 IEI children with COVID-19 have been reported in the literature to date. Although many patients with asymptomatic or mild disease may not have been reported, severe presentation of COVID-19 was observed in 23.6% of the published cases, and the mortality rate was 8.7%. CONCLUSIONS: Young patients with preexisting IEI may have higher mortality than children without IEI when infected with SARS-CoV-2. Elucidating the genetic basis of IEI patients with severe/critical COVID-19 may help to develop better strategies for prevention and treatment of severe COVID-19 disease and complications in pediatric patients.

The Effects of Stimulation with PMA/Ionomycin on CD4+ T Cell Proliferation and Surface CD4 Molecule Modulation of Patients with LRBA Deficiency and CVID with the Unsolved Genetic Defect.

BACKGROUND: Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiencies. LPS-responsive beige-like anchor protein (LRBA) deficiency is a combined immunodeficiency characterized by a CVID-like phenotype. Affected patients by LRBA and CVID present a wide range of clinical manifestations, including hypogammaglobulinemia, recurrent infections, autoimmunity, as well as T cell abnormality. METHODS: The study population comprised of patients with CVID (n=10), LRBA deficiency (n=11), and healthy controls (n=12). CD4+ T cell frequency and CD4 MFI (mean fluorescence intensity) were evaluated using flow cytometry before and after stimulation with PMA/ION. RESULTS: The frequencies of CD4+ T cells were significantly lower in patients with LRBA deficiency than in HCs before and after treatment. In the unstimulated state, the CD4+ T cells frequency in CVID patients was significantly lower than in HCs. There were no statistically significant differences between patients and healthy individuals in CD4+ T cell proliferation. Compared to HCs, LRBA and CVID patients showed a lower CD4 MFI in unstimulated conditions. Furthermore, CD4 MFI decreased in both patients and the control group following activation. CONCLUSION: Despite the reported decrease in CD4+ T cell frequency in patients with CVID and LRBA deficiency, our findings demonstrated that their CD4+ T cells have a normal proliferative response to stimuli similar to healthy individuals.

Evaluation of Expression of LRBA and CTLA-4 Proteins in Common Variable Immunodeficiency Patients.

Common variable immunodeficiency (CVID) is a primary immunodeficiency disease with a heterogeneous genetic background. Lipopolysaccharide-responsive beige-like anchor (LRBA), as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), have important regulatory roles in the immune responses. Here, we have investigated the expression of LRBA and CTLA-4 proteins in CVID patients with at least one presentation of early-onset occurrence, autoimmunity, or enteropathy. In this study, 20 newly diagnosed CVID patients without infection only phenotype, and ten healthy individuals were enrolled. The expressions of LRBA and CTLA-4 proteins were assessed by western blotting and flow cytometry, respectively. The patients were divided into two groups of autoimmunity-positive (11 cases) and autoimmunity-negative (9 patients). LRBA and CTLA-4 expressions were significantly lower in autoimmune-positive patients than in healthy individuals (P = .03 and P = .03, respectively). Autoimmune-negative patients had lower expression of LRBA and CTLA-4 than the control group, although it was not significant. There was a positive correlation between the expressions of LRBA and CTLA-4 in both groups of patients (P < .05). Furthermore, the highest frequency of LRBA (85.7%) and CTLA-4 (71.4%) defects was detected in those with concomitant presence of autoimmunity, enteropathy, and early-onset occurrence. Concurrent presence of autoimmunity, enteropathy, and early-onset occurrence in CVID patients could be indicative of a lack of expression in LRBA and CTLA-4 proteins. This could be helpful in early diagnosis and initiation of appropriate treatment in these patients prior to genetic confirmation.

The spectrum of ATM gene mutations in Iranian patients with ataxia-telangiectasia.

BACKGROUND: Ataxia-telangiectasia (A-T) is a rare genetic disorder characterized by a distinct range of clinical manifestations, including progressive ataxia, immunodeficiency, and radiosensitivity. METHODS: Clinical data, laboratory results, and genetic data were collected from forty-three A-T patients. Whole-exome sequencing and Sanger sequencing were done for the patients clinically diagnosed as suffering from A-T. Based on the phenotype severity of the disease, patients were divided into severe and mild subgroups. RESULTS: The median (IQR) age of diagnosis in this cohort was 5 (3-7) years, and various types of clinical manifestations, including fever (P =.005), lower respiratory tract infection (P = .033), diarrhea (P = .014), and hepatosplenomegaly (P = .032), were significantly higher among patients diagnosed with the severe phenotype. Our results showed a correlation between phenotype severity and mutation type. The chance of having severe phenotype in patients who have severe mutations, including frameshift and nonsense, was 7.3 times higher than in patients who were categorized in the mild genotype group (odds ratio = 7.3, P = .006). Thirty-four types of mutations including 9 novel mutations were observed in our study. CONCLUSION: Molecular analysis provides the opportunity for accurate diagnosis and timely management in A-T patients with chronic progressive disease, especially infections and the risk of malignancies. This study characterizes for the first time the broad spectrum of mutations and phenotypes in Iranian A-T patients, which is required for carrier detection and reducing the burden of disease in the future using the patients' families and for the public healthcare system.

Impact of SARS-CoV-2 Pandemic on Patients with Primary Immunodeficiency.

Although it is estimated that COVID-19 life-threatening conditions may be diagnosed in less than 1:1000 infected individuals below the age of 50, but the real impact of this pandemic on pediatric patients with different types of primary immunodeficiency (PID) is not elucidated. The current prospective study on a national registry of PID patients showed that with only 1.23 folds higher incidence of infections, these patients present a 10-folds higher mortality rate compared to population mainly in patients with combined immunodeficiency and immune dysregulation. Therefore, further management modalities against COVID-19 should be considered to improve the survival rate in these two PID entities using hematopoietic stem cell transplantation and immunomodulatory agents.

Monogenic Primary Immunodeficiency Disorder Associated with Common Variable Immunodeficiency and Autoimmunity.

BACKGROUND: Common variable immunodeficiency (CVID) is the most frequent primary immunodeficiency disorder mainly characterized by recurrent bacterial infections besides other immunological defects including loss of or dysfunction of B cells and decreased immunoglobulin levels. In this study, our aim is to evaluate clinical, immunological, and molecular data of patients with a primary clinical diagnosis of CVID and autoimmune phenotype with a confirmed genetic diagnosis. METHODS: Among 297 patients with CVID, who were registered in the Iranian Primary Immunodeficiency Registry at Children's Medical Center Hospital in Iran, 83 patients have been genetically examined and 27 patients with autoimmunity and confirmed genetic mutations were selected for analysis. Whole-exome sequencing and confirmatory Sanger sequencing methods were used for the study population. A questionnaire was retrospectively filled for all patients to evaluate demographic, laboratory, clinical, and genetic data. RESULTS: In the 27 studied patients, 11 different genetic defects were identified, and the most common mutated gene was LRBA, reported in 17 (63.0%) patients. Two patients (7.7%) showed autoimmune complications as the first presentation of immunodeficiency. Eleven patients (40.7%) developed one type of autoimmunity, and 16 patients (59.3%) progressed to poly-autoimmunity. Most of the patients with mono-autoimmunity (n = 9, 90.0%) primarily developed infectious complications, while in patients with poly-autoimmunity, the most common first presentation was enteropathy (n = 6, 37.6%). In 13 patients (61.9%), the diagnosis of autoimmune disorders preceded the diagnosis of primary immunodeficiency. The most frequent autoimmune manifestations were hematologic (40.7%), gastrointestinal (48.1%), rheumatologic (25.9%), and dermatologic (22.2%) disorders. Patients with poly-autoimmunity had lower regulatory T cells than patients with mono-autoimmunity. CONCLUSION: In our cohort, the diagnosis of autoimmune disorders preceded the diagnosis of primary immunodeficiency in most patients. This association highlights the fact that patients referring with autoimmune manifestations should be evaluated for humoral immunity.

Leishmaniasis and Autoimmunity in Patient with LPS-Responsive Beige-Like Anchor Protein (LRBA) Deficiency.

BACKGROUND/OBJECTIVE: LPS-responsive beige-like anchor protein (LRBA) deficiency is a combined immunodeficiency and immune dysregulation. The authors present a case report of LPSresponsive beige-like anchor protein (LRBA) deficiency with the history of autoimmunity, enteropathy and visceral leishmaniasis. Sirolimus therapy was started for autoimmunity and enteropathy but was discontinued due to recurrent leishmaniasis. Therefore, a common side-effect of many immunosuppressive drugs in patients with LRBA deficiency is increased susceptibility to infections. METHODS: Whole exome sequencing was performed to detect the underlying genetic mutation and Leishmania DNA was detected by the PCR technique in this patient. RESULTS: Whole exome sequencing of the patient reported a homozygous frameshift deletion mutation in the LRBA gene (NM_006726: exon29: c.4638delC, p. S1546fs). Leishmania DNA PCR was positive in this case. CONCLUSION: Parasite infections manifestations report in LRBA deficiency. Leishmania infections in patients with chronic diarrhea and autoimmunity should be considered for immunodeficiency.

Clinical, Immunologic, and Molecular Spectrum of Patients with LPS-Responsive Beige-Like Anchor Protein Deficiency: A Systematic Review.

BACKGROUND: LPS-responsive beige-like anchor protein (LRBA) deficiency is a primary immunodeficiency and immune dysregulation syndrome caused by biallelic mutations in the LRBA gene. These mutations usually abrogate the protein expression of LRBA, leading to a broad spectrum of clinical phenotypes including autoimmunity, chronic diarrhea, hypogammaglobulinemia, and recurrent infections. OBJECTIVE: Our aim was to systematically collect all studies reporting on the clinical manifestations, molecular and laboratory findings, and management of patients with LRBA deficiency. METHODS: We searched in PubMed, Web of Science, and Scopus without any restrictions on study design and publication time. A total of 109 LRBA-deficient cases were identified from 45 eligible articles. For all patients, demographic information, clinical records, and immunologic and molecular data were collected. RESULTS: Of the patients with LRBA deficiency, 93 had homozygous and 16 had compound heterozygous mutations in LRBA. The most common clinical manifestations were autoimmunity (82%), enteropathy (63%), splenomegaly (57%), and pneumonia (49%). Reduction in numbers of CD4+ T cells and regulatory T cells as well as IgG levels was recorded for 21.6%, 65.6%, and 54.2% of evaluated patients, respectively. B-cell subpopulation analysis revealed low numbers of switched-memory and increased numbers of CD21low B cells in 73.5% and 77.8% of patients, respectively. Eighteen (16%) patients underwent hematopoietic stem cell transplantation due to the severity of complications and the outcomes improved in 13 of them. CONCLUSIONS: Autoimmune disorders are the main clinical manifestations of LRBA deficiency. Therefore, LRBA deficiency should be included in the list of monogenic autoimmune diseases, and screening for LRBA mutations should be routinely performed for patients with these conditions.