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.

Reticular dysgenesis: international survey on clinical presentation, transplantation, and outcome.

Reticular dysgenesis (RD) is a rare congenital disorder defined clinically by the combination of severe combined immunodeficiency (SCID), agranulocytosis, and sensorineural deafness. Mutations in the gene encoding adenylate kinase 2 were identified to cause the disorder. Hematopoietic stem cell transplantation (HSCT) is the only option to cure this otherwise fatal disease. Retrospective data on clinical presentation, genetics, and outcome of HSCT were collected from centers in Europe, Asia, and North America for a total of 32 patients born between 1982 and 2011. Age at presentation was <4 weeks in 30 of 32 patients (94%). Grafts originated from mismatched family donors in 17 patients (55%), from matched family donors in 6 patients (19%), and from unrelated marrow or umbilical cord blood donors in 8 patients (26%). Thirteen patients received secondary or tertiary transplants. After transplantation, 21 of 31 patients were reported alive at a mean follow-up of 7.9 years (range: 0.6-23.6 years). All patients who died beyond 6 months after HSCT had persistent or recurrent agranulocytosis due to failure of donor myeloid engraftment. In the absence of conditioning, HSCT was ineffective to overcome agranulocytosis, and inclusion of myeloablative components in the conditioning regimens was required to achieve stable lymphomyeloid engraftment. In comparison with other SCID entities, considerable differences were noted regarding age at presentation, onset, and type of infectious complications, as well as the requirement of conditioning prior to HSCT. Although long-term survival is possible in the presence of mixed chimerism, high-level donor myeloid engraftment should be targeted to avoid posttransplant neutropenia.

Regulatory T-cell deficiency and immune dysregulation, polyendocrinopathy, enteropathy, X-linked-like disorder caused by loss-of-function mutations in LRBA.

BACKGROUND: A number of heritable immune dysregulatory diseases result from defects affecting regulatory T (Treg) cell development, function, or both. They include immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, which is caused by mutations in forkhead box P3 (FOXP3), and IPEX-like disorders caused by mutations in IL-2 receptor α (IL2RA), signal transducer and activator of transcription 5b (STAT5b), and signal transducer and activator of transcription 1 (STAT1). However, the genetic defects underlying many cases of IPEX-like disorders remain unknown. OBJECTIVE: We sought to identify the genetic abnormalities in patients with idiopathic IPEX-like disorders. METHODS: We performed whole-exome and targeted gene sequencing and phenotypic and functional analyses of Treg cells. RESULTS: A child who presented with an IPEX-like syndrome and severe Treg cell deficiency was found to harbor a nonsense mutation in the gene encoding LPS-responsive beige-like anchor (LRBA), which was previously implicated as a cause of common variable immunodeficiency with autoimmunity. Analysis of subjects with LRBA deficiency revealed marked Treg cell depletion; profoundly decreased expression of canonical Treg cell markers, including FOXP3, CD25, Helios, and cytotoxic T lymphocyte-associated antigen 4; and impaired Treg cell-mediated suppression. There was skewing in favor of memory T cells and intense autoantibody production, with marked expansion of T follicular helper and contraction of T follicular regulatory cells. Whereas the frequency of recent thymic emigrants and the differentiation of induced Treg cells were normal, LRBA-deficient T cells exhibited increased apoptosis and reduced activities of the metabolic sensors mammalian target of rapamycin complexes 1 and 2. CONCLUSION: LRBA deficiency is a novel cause of IPEX-like syndrome and Treg cell deficiency associated with metabolic dysfunction and increased apoptosis of Treg cells.

DOCK8 deficiency: clinical and immunological phenotype and treatment options - a review of 136 patients.

Mutations in DOCK8 result in autosomal recessive Hyper-IgE syndrome with combined immunodeficiency (CID). However, the natural course of disease, long-term prognosis, and optimal therapeutic management have not yet been clearly defined. In an international retrospective survey of patients with DOCK8 mutations, focused on clinical presentation and therapeutic measures, a total of 136 patients with a median follow-up of 11.3 years (1.3-47.7) spanning 1693 patient years, were enrolled. Eczema, recurrent respiratory tract infections, allergies, abscesses, viral infections and mucocutaneous candidiasis were the most frequent clinical manifestations. Overall survival probability in this cohort [censored for hematopoietic stem cell transplantation (HSCT)] was 87 % at 10, 47 % at 20, and 33 % at 30 years of age, respectively. Event free survival was 44, 18 and 4 % at the same time points if events were defined as death, life-threatening infections, malignancy or cerebral complications such as CNS vasculitis or stroke. Malignancy was diagnosed in 23/136 (17 %) patients (11 hematological and 9 epithelial cancers, 5 other malignancies) at a median age of 12 years. Eight of these patients died from cancer. Severe, life-threatening infections were observed in 79/136 (58 %); severe non-infectious cerebral events occurred in 14/136 (10 %). Therapeutic measures included antiviral and antibacterial prophylaxis, immunoglobulin replacement and HSCT. This study provides a comprehensive evaluation of the clinical phenotype of DOCK8 deficiency in the largest cohort reported so far and demonstrates the severity of the disease with relatively poor prognosis. Early HSCT should be strongly considered as a potential curative measure.

Successful interferon-alpha 2b therapy for unremitting warts in a patient with DOCK8 deficiency.

The autosomal recessive form of the Hyper IgE syndrome (AR-HIES) with dedicator of cytokinesis 8 (DOCK8) deficiency is associated with difficult to treat persistent viral skin infections, including papilloma virus infection. Type I interferons play an important role in the defense against viruses. We examined the effect of therapy with IFN-α 2b in an 11-year old boy with DOCK8 deficiency due to a homozygous splice donor site mutation in DOCK8 intron 40. His unremitting warts showed dramatic response to IFN-α 2b therapy. Immunological studies revealed decreased circulating plasmacytoid dendritic cells (pDCs) and profound deficiency of IFN-α production by his peripheral blood mononuclear cells in response to treatment with CpG oligonucleotides. These findings indicate that underlying pDC deficiency and impaired IFN-α production may predispose to chronic viral infections in DOCK8 deficiency. IFN-α 2b therapy maybe useful in controlling recalcitrant viral infections in these patients.

Outcome of hematopoietic stem cell transplantation for adenosine deaminase-deficient severe combined immunodeficiency.

Deficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed outcome of HCT in 106 patients with ADA-SCID who received a total of 119 transplants. HCT from matched sibling and family donors (MSDs, MFDs) had significantly better overall survival (86% and 81%) in comparison with HCT from matched unrelated (66%; P < .05) and haploidentical donors (43%; P < .001). Superior overall survival was also seen in patients who received unconditioned transplants in comparison with myeloablative procedures (81% vs 54%; P < .003), although in unconditioned haploidentical donor HCT, nonengraftment was a major problem. Long-term immune recovery showed that regardless of transplant type, overall T-cell numbers were similar, although a faster rate of T-cell recovery was observed after MSD/MFD HCT. Humoral immunity and donor B-cell engraftment was achieved in nearly all evaluable surviving patients and was seen even after unconditioned HCT. These data detail for the first time the outcomes of HCT for ADA-SCID and show that, if patients survive HCT, long-term cellular and humoral immune recovery is achieved.

Infantile Systemic Hyalinosis: A Case Report and Literature Review.

Infantile systemic hyalinosis (ISH) is a very rare disorder belonging to the heterozygous group of genetic fibromatosis. There is a diffuse deposition of hyaline material in the skin, gastrointestinal tract, muscle, lymph node, spleen, thyroid, and adrenal gland due to which it presents clinically with multiple subcutaneous skin nodules, gingival hypertrophy, osteopenia, joint contractures, failure to thrive, and diarrhea with protein-losing enteropathy, and is associated with recurrent infections. The disease is caused by mutations in ANTXR2 also known as the CMG2 gene, which encodes the transmembrane-extracellular matrix assembly. In this report, we describe a nine-month-old male diagnosed with ISH based on the clinical presentation of severe skin lesions, painful joint contractures, diarrhea, and failure to thrive. His diagnosis was confirmed by molecular DNA sequencing of the ANTXR2 gene. Consanguinity and molecular diagnosis will be helpful for early diagnosis and accurate management.

Eosinophilic esophagitis in Saudi children: symptoms, histology and endoscopy results.

BACKGROUND/AIM: Eosinophilic esophagitis (EE) is a clinicopathologic entity characterized by esophageal symptoms in association with a dense eosinophilic infiltrate currently defined as >15 eosinophils per high power field in the appropriate clinical context. This is the first pediatric study in Saudi Arabia to give the experience with EE and examine its symptom, histology and endoscopy results. MATERIALS AND METHODS: Retrospective chart review of all patients diagnosed with EE at National Guard Hospital, Jeddah Between 2007 and 2009. The authors identified EE on histologic criteria (≥15 eosinophils per high-power field) together with their clinical context. The authors reviewed medical records for details of clinical presentation, laboratory data, radiologic, endoscopic, and histologic findings, and the results of treatment. RESULTS: We identified 15 patients in our database in the last three years. 100% of the patients were males. The median age at presentation was 10 years (range, 3-17 years). The commonly reported symptoms were failure to thrive (86%), epigastric abdominal pain (53%), poor eating (40%), dysphagia with solid food (26%), food impaction (13%), and vomiting (20%). Asthma was reported in 46% and allergic rhinitis in 40%. Peripheral eosinophilia (>0.7 Χ 10/l) was found in 66%. High serum IgE Level (>60 IU/ml) was found in 60%. Upper endoscopic analysis revealed esophageal trachealization in 46%, esophageal erythema in 46%, white specks on the esophageal mucosa in 33%, esophageal narrowing in 13%, and normal endoscopy in 13%. The mean eosinophils per high-power field was 30.4 (range, 20-71). Histologic characteristics included degranulated eosinophils (86%), basal cell hyperplasia (93%) and eosinophils clusters (micro-abscess) in 73%. The treatment of EE revealed that they used swallowed corticosteroid in 50%, proton pump inhibitors in 66%, elemental diet/ food elimination in 13% and systemic corticosteroid in 13%. CONCLUSIONS: Failure to thrive and abdominal pain in a male, atopic school-aged child was the most common feature of EE. Peripheral eosinophilia, high serum IgE and endoscopic esophageal erythema and trachealization should significantly raise the clinical index of suspicion for the diagnosis of EE.