Outcome of BCG Vaccination in ADA-SCID Patients: A 12-Patient Series.

Vaccination with Bacillus Calmette-Guérin (BCG) can be harmful to patients with combined primary immunodeficiencies. We report the outcome of BCG vaccination in a series of twelve patients affected by adenosine deaminase deficiency (ADA-SCID). BCG vaccination resulted in a very high incidence of complications due to uncontrolled replication of the mycobacterium. All patients who developed BCG-related disease were treated successfully and remained free from recurrence of disease. We recommend the prompt initiation of enzyme replacement therapy and secondary prophylaxis to reduce the risk of BCG-related complications in ADA-SCID patients.

Quality of Life Evaluation in Saudi Arabian Pediatric Patients with Primary Immunodeficiency Diseases Receiving 20% Subcutaneous IgG Infusions at Home.

BACKGROUND AND AIMS: Subcutaneous immunoglobulin (SCIG) home infusion is widely used as an alternative to intravenous immunoglobulin (IVIG). This study aimed to determine the quality of life (QoL) of patients with primary immunodeficiency (PID) after switching to home-based SCIG. METHODS: In this prospective open-label single-center study, QoL was determined using the validated Arabic version of the Child Health Questionnaire at baseline and 3 and 6 months after switching from IVIG to SCIG. RESULTS: Twenty-four patients were recruited from July 2018 to August 2021, including 14 females and 10 males. The median age of the patients was 5 years (range, 0-14 years). The patients' diagnoses included severe combined immunodeficiency, combined immunodeficiency, agammaglobulinemia, Omenn syndrome, immunodysregulation, hyper-IgE syndrome, common variable immunodeficiency, and bare lymphocyte syndrome. The median duration on IVIG before inclusion was 40 months (range, 5-125 months). The QoL score showed a significant improvement in the patients' global health at 3 and 6 months compared with those at baseline and a significant improvement in the patients' general health at 3 and 6 months compared with that at baseline. The mean baseline serum IgG trough level was 8.8 ± 2.1 g/L. The mean serum IgG level was significantly higher on SCIG at both 3 and 6 months (11.7 ± 2.3 and 11.7 ± 2.5 g/L, respectively). CONCLUSIONS: This is the first study involving an Arab population to show improvement in the QoL of patients with PID after switching from hospital-based IVIG to home-based 20% SCIG.

Genetics of Inborn Errors of Immunity in highly consanguineous Middle Eastern and North African populations.

Consanguineous marriages in Middle Eastern and North African (MENA) countries are deeply-rooted tradition and highly prevalent resulting into increased prevalence of autosomal recessive diseases including Inborn Errors of Immunity (IEIs). Molecular genetic testing is an important diagnostic tool for IEIs since it provides a definite diagnosis, genotype-phenotype correlation, and guide therapy. In this review, we will discuss the current state and challenges of genomic and variome studies in MENA region populations, as well as the importance of funding advanced genome projects. In addition, we will review the MENA underlying molecular genetic defects of over 2457 patients published with the common IEIs, where autosomal recessive mode of inheritance accounts for 76% of cases with increased prevalence of combined immunodeficiency diseases (50%). The efforts made in the last three decades in terms of international collaboration and of in situ capacity building in MENA region countries led to the discovery of more than 150 novel genes involved in IEIs. Expanding sequencing studies within the MENA will undoubtedly be a unique asset for the IEI genetics which can advance research, and support precise genomic diagnostics and therapeutics.

Phenotypic and Genotypic Characterization of Hereditary Angioedema in Saudi Arabia.

Hereditary angioedema (HAE) is a potentially life-threatening autosomal dominant disorder affecting roughly 1:50,000 individuals. It is commonly characterized by swelling of the larynx, gastrointestinal tract, extremities, and skin. There is growing genetic heterogeneity associated with this disease but more than 95% of mutations are found in SERPING1, the gene which encodes complement 1 inhibitor (C1-INH). HAE cohorts from several populations have been published but no large scale study has been reported from the Arab world to date. Here we document the clinical and genetic findings of HAE patients from a single Saudi institution, which is a major referral center at the national level. A total of 51 patients across 17 unrelated families were recruited including two large multi-generational families, of which one contained an in-frame exonic deletion that was resolved through MLPA. Two cases were negative for all the genes we tested (including F12, PLG, ANGPT1, MYOF, KNG1, and HS3ST6). The predominant HAE subtype in our cohort was type I, at 76%. We were able to uncover a mutation in 49 patients (96%). No type III (normal C1-INH) patients were encountered in the clinic, suggesting that this subtype does not play a major role in HAE pathogenesis in Saudi Arabia. Additionally, the existence of four patients with consistently normal complement 4 (C4) levels alongside abnormal C1-INH profiles highlights the utility of dual screening for both proteins in suspected patients.

The Middle East and North Africa Diagnosis and Management Guidelines for Inborn Errors of Immunity.

Human inborn errors of immunity (IEI) are a group of 485 distinct genetic disorders affecting children and adults. Signs and symptoms of IEI are heterogeneous, and accurate diagnosis can be challenging and depends on the available human expertise and laboratory resources. The Middle East and North Africa (MENA) region has an increased prevalence of IEI because of the high rate of consanguinity with a predominance of autosomal recessive disorders. This area also exhibits more severe disease phenotypes compared with other regions, probably due to the delay in diagnosis. The MENA-IEI registry network has designed protocols and guidelines for the diagnosis and treatment of IEI, taking into consideration the variable regional expertise and resources. These guidelines are primarily meant to improve the care of patients within the region, but can also be followed in other regions with similar patient populations.

A homozygous truncating mutation of FGL2 is associated with immune dysregulation.

BACKGROUND: The type II transmembrane protein fibrinogen-like protein 2 (FGL2) plays critical roles in hemostasis and immune regulation. The C-terminal immunoregulatory domain of FGL2 can be secreted and is a mediator of regulatory T (Treg) cell suppression. Fgl2-/- mice develop autoantibodies and glomerulonephritis and have impaired Treg cell function. OBJECTIVE: Our aim was to identify the genetic underpinning and immune function in a patient with childhood onset of leukocytoclastic vasculitis, systemic inflammation, and autoantibodies. METHODS: Whole-exome sequencing was performed on patient genomic DNA. FGL2 protein expression was examined in HEK293 transfected cells by immunoblotting and in PBMCs by flow cytometry. T follicular helper cells and Treg cells were examined by flow cytometry. Treg cell suppression of T-cell proliferation was assessed in vitro. RESULTS: The patient had a homozygous mutation in FGL2 (c.614_617del:p.V205fs), which led to the expression of a truncated FGL2 protein that preserves the N-terminal domain but lacks the C-terminal immunoregulatory domain. The patient had an increased percentage of circulating T follicular helper and Treg cells. The patient's Treg cells had impaired in vitro suppressive ability that was rescued by the addition of full-length FGL2. Unlike full-length FGL2, the truncated FGL2V205fs mutant failed to suppress T-cell proliferation. CONCLUSIONS: We identified a homozygous mutation in FGL2 in a patient with immune dysregulation and impaired Treg cell function. Soluble FGL2 rescued the Treg cell defect, suggesting that it may provide a useful therapy for the patient.

Genetic, Immunological, and Clinical Features of 32 Patients with Autosomal Recessive STAT1 Deficiency.

Autosomal recessive (AR) STAT1 deficiency is a severe inborn error of immunity disrupting cellular responses to type I, II, and III IFNs, and IL-27, and conferring a predisposition to both viral and mycobacterial infections. We report the genetic, immunological, and clinical features of an international cohort of 32 patients from 20 kindreds: 24 patients with complete deficiency, and 8 patients with partial deficiency. Twenty-four patients suffered from mycobacterial disease (bacillus Calmette-Guérin = 13, environmental mycobacteria = 10, or both in 1 patient). Fifty-four severe viral episodes occurred in sixteen patients, mainly caused by Herpesviridae viruses. Attenuated live measles, mumps, and rubella and/or varicella zoster virus vaccines triggered severe reactions in the five patients with complete deficiency who were vaccinated. Seven patients developed features of hemophagocytic syndrome. Twenty-one patients died, and death was almost twice as likely in patients with complete STAT1 deficiency than in those with partial STAT1 deficiency. All but one of the eight survivors with AR complete deficiency underwent hematopoietic stem cell transplantation. Overall survival after hematopoietic stem cell transplantation was 64%. A diagnosis of AR STAT1 deficiency should be considered in children with mycobacterial and/or viral infectious diseases. It is important to distinguish between complete and partial forms of AR STAT1 deficiency, as their clinical outcome and management differ significantly.

Lupus manifestations in children with primary immunodeficiency diseases: Comprehensive phenotypic and genetic features and outcome.

OBJECTIVES: To report the phenotypic, genetic findings and outcome of children with lupus manifestations associated with primary immunodeficiency diseases (PIDs). METHODS: Data are retrospectively collected on patients with lupus manifestations and PIDs seen between 1998 and 2019. Data comprised the clinical findings and genetic testing, the response to treatment and the accrual damage related to SLE. RESULTS: A total of 39 patients (22 female) were reviewed. Thirty-four patients had lupus manifestations and six patients with SLE-like manifestations. Genetic analysis was performed in 25 patients. Complement deficiency was the most frequent PIDs; 26 patients were C1q deficient, three patients had C3 deficiency, two patients had C4 deficiency and one patient with heterozygous C8b variant. The other seven patients had different PIDs genetic defects that include SCID caused by PNP deficiency, CGD, CVID (PIK3CD), IL-2RB mutation, DNase II deficiency, STAT1 mutation, ISG15 mutation and Griscelli syndrome type 3. Mucocutaneous lesions, arthritis and lung involvement were the main clinical features. 84.1% experienced recurrent infections. The mean accrual damage was 2.7 ± 2.2. There were five deaths because of infection. CONCLUSION: This study suggests that patients with lupus manifestations and early onset disease, family history of SLE or recurrent infections should undergo immunological work-up and genetic testing to rule out PIDs.

Hematological findings associated with tubulin-folding cofactors D-related encephalopathy: Expanding the phenotype.

The dysfunction of microtubules (α/ß-tubulin polymers) underlies a wide range of nervous system genetic abnormalities. Defects in TBCD, a tubulin-folding cofactor, cause diseases highlighted with early-onset encephalopathy with or without neurodegeneration, intellectual disability, seizures, microcephaly and tetraparaperesis. Utilizing various molecular methods, we describe nine patients from four unrelated families with two novel exon 18 variants in TBCD exhibiting the typical neurological phenotype of the disease. Interestingly, all the investigated patients had previously unreported hematological findings in the form of neutropenia and mild degree of anemia and thrombocytopenia. In addition to delineating the neurological phenotype in several patients with TBCD variants, our study stresses on the new association of neutropenia, in particular, with the disease.

Proteomics Profiling to Distinguish DOCK8 Deficiency From Atopic Dermatitis.

Dedicator of cytokinesis 8 deficiency is an autosomal recessive primary immune deficiency disease belonging to the group of hyperimmunoglobulinemia E syndrome (HIES). The clinical phenotype of dedicator of cytokinesis 8 (DOCK8) deficiency, characterized by allergic manifestations, increased infections, and increased IgE levels, overlaps with the clinical presentation of atopic dermatitis (AD). Despite the identification of metabolomics and cytokine biomarkers, distinguishing between the two conditions remains clinically challenging. The present study used a label-free untargeted proteomics approach using liquid-chromatography mass spectrometry with network pathway analysis to identify the differentially regulated serum proteins and the associated metabolic pathways altered between the groups. Serum samples from DOCK8 (n = 10), AD (n = 9) patients and healthy control (Ctrl) groups (n = 5) were analyzed. Based on the proteomics profile, the PLS-DA score plot between the three groups showed a clear group separation and sample clustering (R2 = 0.957, Q2 = 0.732). Significantly differentially abundant proteins (p < 0.05, FC cut off 2) were identified between DOCK8-deficient and AD groups relative to Ctrl (n = 105, and n = 109) and between DOCK8-deficient and AD groups (n = 85). Venn diagram analysis revealed a differential regulation of 24 distinct proteins from among the 85 between DOCK8-deficient and AD groups, including claspin, haptoglobin-related protein, immunoglobulins, complement proteins, fibulin, and others. Receiver-operating characteristic curve (ROC) analysis identified claspin and haptoglobin-related protein, as potential biomarkers with the highest sensitivity and specificity (AUC = 1), capable of distinguishing between patients with DOCK8 deficiency and AD. Network pathway analysis between DOCK8-deficiency and AD groups revealed that the identified proteins centered around the dysregulation of ERK1/2 signaling pathway. Herein, proteomic profiling of DOCK8-deficiency and AD groups was carried out to determine alterations in the proteomic profiles and identify a panel of the potential proteomics biomarker with possible diagnostic applications. Distinguishing between DOCK8-deficiency and AD will help in the early initiation of treatment and preventing complications.

Clinical and Immunological Characterization of Combined Immunodeficiency Due to TFRC Mutation in Eight Patients.

PURPOSE: Combined immunodeficiency (CID), due to mutations in TFRC gene that encodes the transferrin receptors (TfR1), is a rare monogenic disorder. In this study, we further characterize the clinical and immunological phenotypes in a cohort of eight patients. METHODS: A retrospective review of clinical and immunological features of patients diagnosed with a TFRC gene mutation between 2015 and 2019 in three tertiary centers. RESULTS: Eight patients from six unrelated families were enrolled. The patients had a median age of 7 years (4-32 years). All patients presented with recurrent sinopulmonary infections, chronic diarrhea, and failure to thrive in early life. Less common features were skin abscesses, conjunctivitis, global developmental delay, optic nerve atrophy, vitiligo, multinodular goiter, and hemophagocytic lymphohistiocytosis-like symptoms. All patients had intermittent neutropenia and 87% of the patients had recurrent thrombocytopenia. Anemia was found in 62%. All patients had hypogammaglobinemia and one had a persistent high IgM level. All patients had impaired function of T cells. The same homozygous missense mutation c.58T>C:p.Y20H, in the TFRC gene, was detected in all patients. Stem cell transplantation from matched donors was successful in two patients. Five patients did not receive stem cell transplantation, and they are on prophylactic treatment. One patient died due to severe sepsis and neurological complications. CONCLUSION: This report provides a large cohort with a long follow up of patients with this disease. Our cohort showed variable disease severity.

Multiple Family Members With Delayed Cord Separtion and Combined Immunodeficiency With Novel Mutation in IKBKB.

Background: Inhibitor of kappa kinase 2 (IKK2) deficiency is a recently described combined immunodeficiency. It undermines the nuclear factor-kappa B (NF-κB) activation pathway. Methods: The clinical and immunological data of four patients diagnosed with combined immunodeficiency (CID) from two related Saudi families were collected. Autozygosity mapping of all available members and whole exome sequencing of the index case were performed to define the genetic etiology. Results: The patients had early onset (2-4 months of age) severe infections caused by viruses, bacteria, mycobacteria, and fungi. They all had hypogammaglobulinemia and low absolute lymphocyte count. Their lymphocytes failed to respond to PHA mitogen stimulation. A novel homozygous non-sense mutation in the IKBKB gene, c.850C>T (p. Arg284*) was identified in the index patient and segregated with the disease in the rest of the family. He underwent hematopoietic stem cell transplantation (HSCT) from a fully matched sibling with no conditioning. The other three patients succumbed to their disease. Interestingly, all patients had delayed umbilical cord separation. Conclusion: IKK2 deficiency causes CID with high mortality. Immune reconstitution with HSCT should be considered as early as possible. Delayed umbilical cord separation in CID patients may be a clue to IKK2 deficiency.

PAX1 is essential for development and function of the human thymus.

We investigated the molecular and cellular basis of severe combined immunodeficiency (SCID) in six patients with otofaciocervical syndrome type 2 who failed to attain T cell reconstitution after allogeneic hematopoietic stem cell transplantation, despite successful engraftment in three of them. We identified rare biallelic PAX1 rare variants in all patients. We demonstrated that these mutant PAX1 proteins have an altered conformation and flexibility of the paired box domain and reduced transcriptional activity. We generated patient-derived induced pluripotent stem cells and differentiated them into thymic epithelial progenitor cells and found that they have an altered transcriptional profile, including for genes involved in the development of the thymus and other tissues derived from pharyngeal pouches. These results identify biallelic, loss-of-function PAX1 mutations as the cause of a syndromic form of SCID due to altered thymus development.

Improved transplant survival and long-term disease outcome in children with MHC class II deficiency.

MHC class II deficiency is a rare, but life-threatening, primary combined immunodeficiency. Hematopoietic cell transplantation (HCT) remains the only curative treatment for this condition, but transplant survival in the previously published result was poor. We analyzed the outcome of 25 patients with MHC class II deficiency undergoing first HCT at Great North Children's Hospital between 1995 and 2018. Median age at diagnosis was 6.5 months (birth to 7.5 years). Median age at transplant was 21.4 months (0.1-7.8 years). Donors were matched family donors (MFDs; n = 6), unrelated donors (UDs; n = 12), and haploidentical donors (HIDs; n = 7). Peripheral blood stem cells were the stem cell source in 68% of patients. Conditioning was treosulfanbased in 84% of patients; 84% received alemtuzumab (n = 14) or anti-thymocyte globulin (n = 8) as serotherapy. With a 2.9-year median follow-up, OS improved from 33% (46-68%) for HCT before 2008 (n = 6) to 94% (66-99%) for HCT after 2008 (n = 19; P = .003). For HCT after 2008, OS according to donor was 100% for MFDs and UDs and 85% for HIDs (P = .40). None had grade III-IV acute or chronic graft-versus-host disease. Latest median donor myeloid and lymphocyte chimerism were 100% (range, 0-100) and 100% (range, 64-100), respectively. Latest CD4+ T-lymphocyte number was significantly lower in transplant survivors (n = 14) compared with posttransplant disease controls (P = .01). All survivors were off immunoglobulin replacement and had protective vaccine responses to tetanus and Haemophilus influenzae. None had any significant infection or autoimmunity. Changing transplant strategy in Great North Children's Hospital has significantly improved outcomes for MHC class II deficiency.

Hypomorphic variants in AK2 reveal the contribution of mitochondrial function to B-cell activation.

BACKGROUND: The gene AK2 encodes the phosphotransferase adenylate kinase 2 (AK2). Human variants in AK2 cause reticular dysgenesis, a severe combined immunodeficiency with agranulocytosis, lymphopenia, and sensorineural deafness that requires hematopoietic stem cell transplantation for survival. OBJECTIVE: We investigated the mechanisms underlying recurrent sinopulmonary infections and hypogammaglobulinemia in 15 patients, ranging from 3 to 34 years of age, from 9 kindreds. Only 2 patients, both of whom had mildly impaired T-cell proliferation, each had a single clinically significant opportunistic infection. METHODS: Patient cells were studied with next-generation DNA sequencing, tandem mass spectrometry, and assays of lymphocyte and mitochondrial function. RESULTS: We identified 2 different homozygous variants in AK2. AK2G100S and AK2A182D permit residual protein expression, enzymatic activity, and normal numbers of neutrophils and lymphocytes. All but 1 patient had intact hearing. The patients' B cells had severely impaired proliferation and in vitro immunoglobulin secretion. With activation, the patients' B cells exhibited defective mitochondrial respiration and impaired regulation of mitochondrial membrane potential and quality. Although activated T cells from the patients with opportunistic infections demonstrated impaired mitochondrial function, the mitochondrial quality in T cells was preserved. Consistent with the capacity of activated T cells to utilize nonmitochondrial metabolism, these findings revealed a less strict cellular dependence of T-cell function on AK2 activity. Chemical inhibition of ATP synthesis in control T and B cells similarly demonstrated the greater dependency of B cells on mitochondrial function. CONCLUSIONS: Our patients demonstrate the in vivo sequelae of the cell-specific requirements for the functions of AK2 and mitochondria, particularly in B-cell activation and antibody production.

Metabolomics Distinguishes DOCK8 Deficiency from Atopic Dermatitis: Towards a Biomarker Discovery.

Bi-allelic mutations in the dedicator of cytokinesis 8 (DOCK8) are responsible for a rare autosomal recessive primary combined immunodeficiency syndrome, characterized by atopic dermatitis, elevated serum Immunoglobulin E (IgE) levels, recurrent severe cutaneous viral infections, autoimmunity, and predisposition to malignancy. The molecular link between DOCK8 deficiency and atopic skin inflammation remains unknown. Severe atopic dermatitis (AD) and DOCK8 deficiency share some clinical symptoms, including eczema, eosinophilia, and increased serum IgE levels. Increased serum IgE levels are characteristic of, but not specific to allergic diseases. Herein, we aimed to study the metabolomic profiles of DOCK8-deficient and AD patients for potential disease-specific biomarkers using chemical isotope labeling liquid chromatography-mass spectrometry (CIL LC-MS). Serum samples were collected from DOCK8-deficient (n = 10) and AD (n = 9) patients. Metabolomics profiling using CIL LC-MS was performed on patient samples and compared to unrelated healthy controls (n = 33). Seven metabolites were positively identified, distinguishing DOCK8-deficient from AD patients. Aspartic acid and 3-hydroxyanthranillic acid (3HAA, a tryptophan degradation pathway intermediate) were up-regulated in DOCK8 deficiency, whereas hypotaurine, leucyl-phenylalanine, glycyl-phenylalanine, and guanosine were down-regulated. Hypotaurine, 3-hydroxyanthranillic acid, and glycyl-phenyalanine were identified as potential biomarkers specific to DOCK8 deficiency. Aspartate availability has been recently implicated as a limiting metabolite for tumour growth and 3HAA; furthermore, other tryptophan metabolism pathway-related molecules have been considered as potential novel targets for cancer therapy. Taken together, perturbations in tryptophan degradation and increased availability of aspartate suggest a link of DOCK8 deficiency to oncogenesis. Additionally, perturbations in taurine and dipeptides metabolism suggest altered antixidation and cell signaling states in DOCK8 deficiency. Further studies examining the mechanisms underlying these observations are necessary.

Human interleukin-2 receptor ß mutations associated with defects in immunity and peripheral tolerance.

Interleukin-2, which conveys essential signals for immunity, operates through a heterotrimeric receptor. Here we identify human interleukin-2 receptor (IL-2R) ß chain (IL2RB) gene defects as a cause of life-threatening immune dysregulation. We report three homozygous mutations in the IL2RB gene of eight individuals from four consanguineous families that cause disease by distinct mechanisms. Nearly all patients presented with autoantibodies, hypergammaglobulinemia, bowel inflammation, dermatological abnormalities, lymphadenopathy, and cytomegalovirus disease. Patient T lymphocytes lacked surface expression of IL-2Rß and were unable to respond to IL-2 stimulation. By contrast, natural killer cells retained partial IL-2Rß expression and function. IL-2Rß loss of function was recapitulated in a recombinant system in which IL2RB mutations caused reduced surface expression and IL-2 binding. Stem cell transplant ameliorated clinical symptoms in one patient; forced expression of wild-type IL-2Rß also increased the IL-2 responsiveness of patient T lymphocytes in vitro. Insights from these patients can inform the development of IL-2-based therapeutics for immunological diseases and cancer.

Graft Versus Host Disease Following HLA-Matched Sibling Donor Compared with Matched Related Donor for Hematopoietic Stem Cell Transplantation for the Treatment of Severe Combined Immunodeficiency Disease.

BACKGROUND: One of the limiting factors for successful hematopoietic stem cell transplantation (HSCT) is graft versus host disease (GVHD). The EBMT/ESID guidelines for HSCT in severe combined immunodeficiency (SCID) recommend no GVHD prophylaxis for a matched sibling donor (MSD). OBJECTIVE: To determine the risk of GVHD in MSD HSCT for SCID patients compared to matched related donor (MRD). METHODS: This retrospective cohort study compares MSD with MRD and the outcome of GVHD in all SCID patients who underwent HSCT between 1993 and 2013. All statistical analyses were done using IBM SPSS statistics software. RESULTS: One hundred forty-five SCID patients underwent 152 HSCTs while 82 (54%) received GVHD prophylaxis. GVHD occurred in 48 patients (31.5%); 20/48 (42%) had GVHD prophylaxis compared to 28/48 (58%) that did not, P = 0.022. Acute GVHD occurred at a higher trend in MSD, 37/120 (30.8%), compared to MRD, 6/32 (18.8%), P = 0.17. We also analyzed the outcome according to the period of HSCT. The first period was 1993 to 2003, 48 HSCTs, 43 MSD, 5 MRD; all patients had GVHD prophylaxis, and there was no difference in GVHD. The second period was 2004 to 2013: of 104 HSCTs, 77 had MSD and 27 had MRD; GVHD prophylaxis was used in 22.1% of MSD and 63% of MRD, P = 0.000. GVHD was significantly higher in the MSD (40.2%) compared to MRD (18.5%) patients, P = 0.041. CONCLUSION: GVHD prophylaxis in MSD transplant should be considered in SCID patients.