Rapamycin Controls Lymphoproliferation and Reverses T-Cell Responses in a Patient with a Novel STIM1 Loss-of-Function Deletion.

PURPOSE: Deficiency of stromal interaction molecule 1 (STIM1) results in combined immunodeficiency accompanied by extra-immunological findings like enamel defects and myopathy. We here studied a patient with a STIM1 loss-of-function mutation who presented with severe lymphoproliferation. We sought to explore the efficacy of the mTOR inhibitor rapamycin in controlling disease manifestations and reversing aberrant T-cell subsets and functions, which has never been used previously in this disorder. METHODS: Clinical findings of the patient were collected over time. We performed immunological evaluations before and after initiation of rapamycin treatment, including detailed lymphocyte subset analyses, alterations in frequencies of circulating T follicular helper (cTFH) and regulatory T (Treg) cells and their subtypes as well as T cell activation and proliferation capacities. RESULTS: A novel homozygous exon 2 deletion in STIM1 was detected in a 3-year-old girl with severe lymphoproliferation, recurrent infections, myopathy, iris hypoplasia, and enamel hypoplasia. Lymphoproliferation was associated with severe T-cell infiltrates. The deletion resulted in a complete loss of protein expression, associated with a lack of store-operated calcium entry response, defective T-cell activation, proliferation, and cytokine production. Interestingly, patient blood contained fewer cTFH and increased circulating follicular regulatory (cTFR) cells. Abnormal skewing towards TH2-like responses in certain T-cell subpopulations like cTFH, non-cTFH memory T-helper, and Treg cells was associated with increased eosinophil numbers and serum IgE levels. Treatment with rapamycin controlled lymphoproliferation, improved T-cell activation and proliferation capacities, reversed T-cell responses, and repressed high IgE levels and eosinophilia. CONCLUSIONS: This study enhances our understanding of STIM1 deficiency by uncovering additional abnormal T-cell responses, and reveals for the first time the potential therapeutic utility of rapamycin for this disorder.

Regulatory T-cell dysfunction and cutaneous exposure to Staphylococcus aureus underlie eczema in DOCK8 deficiency.

BACKGROUND: Dedicator of cytokinesis 8 (DOCK8)-deficient patients have severe eczema, elevated IgE, and eosinophilia, features of atopic dermatitis (AD). OBJECTIVE: We sought to understand the mechanisms of eczema in DOCK8 deficiency. METHODS: Skin biopsy samples were characterized by histology, immunofluorescence microscopy, and gene expression. Skin barrier function was measured by transepidermal water loss. Allergic skin inflammation was elicited in mice by epicutaneous sensitization with ovalbumin (OVA) or cutaneous application of Staphylococcus aureus. RESULTS: Skin lesions of DOCK8-deficient patients exhibited type 2 inflammation, and the patients' skin was colonized by Saureus, as in AD. Unlike in AD, DOCK8-deficient patients had a reduced FOXP3:CD4 ratio in their skin lesions, and their skin barrier function was intrinsically intact. Dock8-/- mice exhibited reduced numbers of cutaneous T regulatory (Treg) cells and a normal skin barrier. Dock8-/- and mice with an inducible Dock8 deletion in Treg cells exhibited increased allergic skin inflammation after epicutaneous sensitization with OVA. DOCK8 was shown to be important for Treg cell stability at sites of allergic inflammation and for the generation, survival, and suppressive activity of inducible Treg cells. Adoptive transfer of wild-type, but not DOCK8-deficient, OVA-specific, inducible Treg cells suppressed allergic inflammation in OVA-sensitized skin of Dock8-/- mice. These mice developed severe allergic skin inflammation and elevated serum IgE levels after topical exposure to Saureus. Both were attenuated after adoptive transfer of WT but not DOCK8-deficient Treg cells. CONCLUSION: Treg cell dysfunction increases susceptibility to allergic skin inflammation in DOCK8 deficiency and synergizes with cutaneous exposure to Saureus to drive eczema in DOCK8 deficiency.

Expanding the clinical and immunological phenotypes of PAX1-deficient SCID and CID patients.

Paired box 1 (PAX1) deficiency has been reported in a small number of patients diagnosed with otofaciocervical syndrome type 2 (OFCS2). We described six new patients who demonstrated variable clinical penetrance. Reduced transcriptional activity of pathogenic variants confirmed partial or complete PAX1 deficiency. Thymic aplasia and hypoplasia were associated with impaired T cell immunity. Corrective treatment was required in 4/6 patients. Hematopoietic stem cell transplantation resulted in poor immune reconstitution with absent naïve T cells, contrasting with the superior recovery of T cell immunity after thymus transplantation. Normal ex vivo differentiation of PAX1-deficient CD34+ cells into mature T cells demonstrated the absence of a hematopoietic cell-intrinsic defect. New overlapping features with DiGeorge syndrome included primary hypoparathyroidism (n = 5) and congenital heart defects (n = 2), in line with PAX1 expression during early embryogenesis. Our results highlight new features of PAX1 deficiency, which are relevant to improving early diagnosis and identifying patients requiring corrective treatment.

Outcomes of hematopoietic stem cell gene therapy for Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked disorder characterized by combined immunodeficiency, eczema, microthrombocytopenia, autoimmunity, and lymphoid malignancies. Gene therapy (GT) to modify autologous CD34+ cells is an emerging alternative treatment with advantages over standard allogeneic hematopoietic stem cell transplantation for patients who lack well-matched donors, avoiding graft-versus-host-disease. We report the outcomes of a phase 1/2 clinical trial in which 5 patients with severe WAS underwent GT using a self-inactivating lentiviral vector expressing the human WAS complementary DNA under the control of a 1.6-kB fragment of the autologous promoter after busulfan and fludarabine conditioning. All patients were alive and well with sustained multilineage vector gene marking (median follow-up: 7.6 years). Clinical improvement of eczema, infections, and bleeding diathesis was universal. Immune function was consistently improved despite subphysiologic levels of transgenic WAS protein expression. Improvements in platelet count and cytoskeletal function in myeloid cells were most prominent in patients with high vector copy number in the transduced product. Two patients with a history of autoimmunity had flares of autoimmunity after GT, despite similar percentages of WAS protein-expressing cells and gene marking to those without autoimmunity. Patients with flares of autoimmunity demonstrated poor numerical recovery of T cells and regulatory T cells (Tregs), interleukin-10-producing regulatory B cells (Bregs), and transitional B cells. Thus, recovery of the Breg compartment, along with Tregs appears to be protective against development of autoimmunity after GT. These results indicate that clinical and laboratory manifestations of WAS are improved with GT with an acceptable safety profile. This trial is registered at clinicaltrials.gov as #NCT01410825.

Activated phosphoinositide 3-kinase δ syndrome: Update from the ESID Registry and comparison with other autoimmune-lymphoproliferative inborn errors of immunity.

BACKGROUND: Activated phosphoinositide-3-kinase δ syndrome (APDS) is an inborn error of immunity (IEI) with infection susceptibility and immune dysregulation, clinically overlapping with other conditions. Management depends on disease evolution, but predictors of severe disease are lacking. OBJECTIVES: This study sought to report the extended spectrum of disease manifestations in APDS1 versus APDS2; compare these to CTLA4 deficiency, NFKB1 deficiency, and STAT3 gain-of-function (GOF) disease; and identify predictors of severity in APDS. METHODS: Data was collected from the ESID (European Society for Immunodeficiencies)-APDS registry and was compared with published cohorts of the other IEIs. RESULTS: The analysis of 170 patients with APDS outlines high penetrance and early onset of APDS compared to the other IEIs. The large clinical heterogeneity even in individuals with the same PIK3CD variant E1021K illustrates how poorly the genotype predicts the disease phenotype and course. The high clinical overlap between APDS and the other investigated IEIs suggests relevant pathophysiological convergence of the affected pathways. Preferentially affected organ systems indicate specific pathophysiology: bronchiectasis is typical of APDS1; interstitial lung disease and enteropathy are more common in STAT3 GOF and CTLA4 deficiency. Endocrinopathies are most frequent in STAT3 GOF, but growth impairment is also common, particularly in APDS2. Early clinical presentation is a risk factor for severe disease in APDS. CONCLUSIONS: APDS illustrates how a single genetic variant can result in a diverse autoimmune-lymphoproliferative phenotype. Overlap with other IEIs is substantial. Some specific features distinguish APDS1 from APDS2. Early onset is a risk factor for severe disease course calling for specific treatment studies in younger patients.

Human CARMIL2 deficiency underlies a broader immunological and clinical phenotype than CD28 deficiency.

Patients with inherited CARMIL2 or CD28 deficiency have defective T cell CD28 signaling, but their immunological and clinical phenotypes remain largely unknown. We show that only one of three CARMIL2 isoforms is produced and functional across leukocyte subsets. Tested mutant CARMIL2 alleles from 89 patients and 52 families impair canonical NF-κB but not AP-1 and NFAT activation in T cells stimulated via CD28. Like CD28-deficient patients, CARMIL2-deficient patients display recalcitrant warts and low blood counts of CD4+ and CD8+ memory T cells and CD4+ TREGs. Unlike CD28-deficient patients, they have low counts of NK cells and memory B cells, and their antibody responses are weak. CARMIL2 deficiency is fully penetrant by the age of 10 yr and is characterized by numerous infections, EBV+ smooth muscle tumors, and mucocutaneous inflammation, including inflammatory bowel disease. Patients with somatic reversions of a mutant allele in CD4+ T cells have milder phenotypes. Our study suggests that CARMIL2 governs immunological pathways beyond CD28.

Monogenic early-onset lymphoproliferation and autoimmunity: Natural history of STAT3 gain-of-function syndrome.

BACKGROUND: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. OBJECTIVE: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. METHODS: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. RESULTS: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4-CD8-) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. CONCLUSION: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.

A Stk4-Foxp3-NF-κB p65 transcriptional complex promotes Treg cell activation and homeostasis.

The molecular programs involved in regulatory T (Treg) cell activation and homeostasis remain incompletely understood. Here, we show that T cell receptor (TCR) signaling in Treg cells induces the nuclear translocation of serine/threonine kinase 4 (Stk4), leading to the formation of an Stk4-NF-κB p65-Foxp3 complex that regulates Foxp3- and p65-dependent transcriptional programs. This complex was stabilized by Stk4-dependent phosphorylation of Foxp3 on serine-418. Stk4 deficiency in Treg cells, either alone or in combination with its homolog Stk3, precipitated a fatal autoimmune lymphoproliferative disease in mice characterized by decreased Treg cell p65 expression and nuclear translocation, impaired NF-κB p65-Foxp3 complex formation, and defective Treg cell activation. In an adoptive immunotherapy model, overexpression of p65 or the phosphomimetic Foxp3S418E in Stk3/4-deficient Treg cells ameliorated their immune regulatory defects. Our studies identify Stk4 as an essential TCR-responsive regulator of p65-Foxp3-dependent transcription that promotes Treg cell-mediated immune tolerance.

Clinical, immunological, molecular and therapeutic findings in monogenic immune dysregulation diseases: Middle East and North Africa registry.

Monogenic immune dysregulation diseases (MIDD) are caused by defective immunotolerance. This study was designed to increase knowledge on the prevalence and spectrum of MIDDs, genetic patterns, and outcomes in Middle East and North Africa (MENA). MIDD patients from 11 MENA countries (Iran, Turkey, Kuwait, Oman, Algeria, Egypt, United Arab Emirates, Tunisia, Jordan, Qatar, and Azerbaijan) were retrospectively evaluated. 343 MIDD patients (58% males and 42% female) at a median (IQR) age of 101 (42-192) months were enrolled. The most common defective genes were LRBA (23.9%), LYST (8.2%), and RAB27A (7.9%). The most prevalent initial and overall manifestations were infections (32.2% and 75.1%), autoimmunity (18.6% and 41%), and organomegaly (13.3% and 53.8%), respectively. Treatments included immunoglobulin replacement therapy (53%), hematopoietic stem cell transplantation (HSCT) (14.3%), immunosuppressives (36.7%), and surgery (3.5%). Twenty-nine (59.2%) patients survived HSCT. Along with infectious complications, autoimmunity and organomegaly may be the initial or predominant manifestations of MIDD.

Increased radiosensitivity and impaired DNA repair in patients with STAT3-LOF and ZNF341 deficiency, potentially contributing to malignant transformations.

STAT3 plays an important role in various complex and sometimes contradictory pathways such as proliferation, differentiation, migration, inflammation, and apoptosis. The transcriptional activity of the STAT3 gene is controlled by a transcription factor called ZNF341. There is insufficient data on radiation sensitivity and post-radiation DNA repair in STAT3- loss-of-function (LOF) patients. We aimed to investigate the radiosensitivity in patients with STAT3-LOF and ZNF341 deficiency. Twelve patients with STAT3-LOF and four ZNF341-deficiency patients were recruited from three clinical immunology centers in Turkey and evaluated for radiosensitivity by the Comet assay, comparing to 14 age- and sex-matched healthy controls. The tail length (TL) (µm), percentage of DNA in the tail (TDNA%), and olive tail moment (OTM) (arbitrary units) were evaluated at the same time for baseline (spontaneous), initial (immediately after 2 Gy irradiation), and recovery (2 h after irradiation) periods by using a computerized image-analysis system, estimating DNA damage. Except for a patient with ZNF341 deficiency who developed nasal cell primitive neuroendocrine tumor and papillary thyroid cancer during the follow-up, there was no cancer in both groups. During the recovery period of irradiation, TL, TDNA%, and OTM values of healthy controls decreased rapidly toward the baseline, while these values of patients with STAT3-LOF and ZNF341 deficiency continued to increase, implying impaired DNA repair mechanisms. Increased radiosensitivity and impaired DNA repair were demonstrated in patients diagnosed with STAT3-LOF and ZNF341 deficiency, potentially explaining the susceptibility to malignant transformation.

Comparing the levels of CTLA-4-dependent biological defects in patients with LRBA deficiency and CTLA-4 insufficiency.

BACKGROUND: Lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency and cytotoxic T-lymphocyte protein-4 (CTLA-4) insufficiency are recently described disorders that present with susceptibility to infections, autoimmunity, and lymphoproliferation. Clinical and immunological comparisons of the diseases with long-term follow-up have not been previously reported. We sought to compare the clinical and laboratory manifestations of both diseases and investigate the role of flow cytometry in predicting the genetic defect in patients with LRBA deficiency and CTLA-4 insufficiency. METHODS: Patients were evaluated clinically with laboratory assessments for lymphocyte subsets, T follicular helper cells (TFH ), LRBA expression, and expression of CD25, FOXP3, and CTLA4 in regulatory T cells (Tregs) at baseline and 16 h post-stimulation. RESULTS: LRBA-deficient patients (n = 29) showed significantly early age of symptom onset, higher rates of pneumonia, autoimmunity, chronic diarrhea, and failure to thrive compared to CTLA-4 insufficiency (n = 12). In total, 29 patients received abatacept with favorable responses and the overall survival probability was not different between transplanted versus non-transplanted patients in LRBA deficiency. Meanwhile, higher probability of survival was observed in CTLA-4-insufficient patients (p = 0.04). The T-cell subsets showed more deviation to memory cells in CTLA-4-insufficiency, accompanied by low percentages of Treg and dysregulated cTFH cells response in both diseases. Cumulative numbers of autoimmunities positively correlated with cTFH frequencies. Baseline CTLA-4 expression was significantly diminished in LRBA deficiency and CTLA-4 insufficiency, but significant induction in CTLA-4 was observed after short-term T-cell stimulation in LRBA deficiency and controls, while this elevation was less in CTLA-4 insufficiency, allowing to differentiate this disease from LRBA deficiency with high sensitivity (87.5%) and specificity (90%). CONCLUSION: This cohort provided detailed clinical and laboratory comparisons for LRBA deficiency and CTLA-4 insufficiency. The flow cytometric approach is useful in predicting the defective gene; thus, targeted sequencing can be conducted to provide rapid diagnosis and treatment for these diseases impacting the CTLA-4 pathway.

Clinical and Laboratory Factors Affecting the Prognosis of Severe Combined Immunodeficiency.

PURPOSE: Severe combined immunodeficiency (SCID) is one of the most severe forms of inborn errors of immunity characterized by absence or loss of function in T cells. The long-term outcomes of all forms of SCID have been evaluated in a limited number of studies. We aimed to evaluate the pre- and post-transplant manifestations of SCID patients and determine the factors affecting the survival of patients. METHODS: We included 54 SCID patients (classical SCID, Omenn syndrome, atypical SCID (AS)) in this study. We evaluated the clinical presentation, infections, and outcome of hematopoietic stem cell transplantation (HSCT). Lymphocyte subsets and T-cell receptor (TCR) repertoire were analyzed by flow cytometry. RESULTS: The median age at diagnosis was 5 (range: 3-24) months and follow-up time was 25 (range: 5-61) months. Symptom onset and diagnostic ages were significantly higher in AS compared to others (p = 0.001; p < 0.001). The most common SCID phenotype was T-B-NK + , and mutations in recombination-activating genes (RAG1/2) were the prominent genetic defect among patients. The overall survival (OS) rate was 83.3% after HSCT, higher than in non-transplanted patients (p = 0.001). Peripheral blood stem cell sources and genotypes other than RAG had a significant favorable impact on CD4+ T cells immune reconstitution after transplantation (p = 0.044, p = 0.035; respectively). Gender matching transplantations from human leukocyte antigen (HLA)-identical and non-identical donors and using peripheral blood stem cell source yielded higher B-cell reconstitution (p = 0.002, p = 0.028; respectively). Furthermore, receiving a conditioning regimen provided better B-cell reconstitution and chimerism (p = 0.003, p = 0.001). Post-transplant TCR diversity was sufficient in the patients and showed an equal distribution pattern as healthy controls. The OS rate was lower in patients who underwent transplant with active infection or received stem cells from mismatched donors (p = 0.030, p = 0.015; respectively). CONCLUSION: This study identifies diagnostic and therapeutic approaches predictive of favorable outcomes for patients with SCID.

Low Density Granulocytes and Dysregulated Neutrophils Driving Autoinflammatory Manifestations in NEMO Deficiency.

NF-κB essential modulator (NEMO, IKK-γ) deficiency is a rare combined immunodeficiency caused by mutations in the IKBKG gene. Conventionally, patients are afflicted with life threatening recurrent microbial infections. Paradoxically, the spectrum of clinical manifestations includes severe inflammatory disorders. The mechanisms leading to autoinflammation in NEMO deficiency are currently unknown. Herein, we sought to investigate the underlying mechanisms of clinical autoinflammatory manifestations in a 12-years old male NEMO deficiency (EDA-ID, OMIM #300,291) patient by comparing the immune profile of the patient before and after hematopoietic stem cell transplantation (HSCT). Response to NF-kB activators were measured by cytokine ELISA. Neutrophil and low-density granulocyte (LDG) populations were analyzed by flow cytometry. Peripheral blood mononuclear cells (PBMC) transcriptome before and after HSCT and transcriptome of sorted normal-density neutrophils and LDGs were determined using the NanoString nCounter gene expression panels. ISG15 expression and protein ISGylation was based on Immunoblotting. Consistent with the immune deficiency, PBMCs of the patient were unresponsive to toll-like and T cell receptor-activators. Paradoxically, LDGs comprised 35% of patient PBMCs and elevated expression of genes such as MMP9, LTF, and LCN2 in the granulocytic lineage, high levels of IP-10 in the patient's plasma, spontaneous ISG15 expression and protein ISGylation indicative of a spontaneous type I interferon (IFN) signature were observed, all of which normalized after HSCT. Collectively, our results suggest that type I IFN signature observed in the patient, dysregulated LDGs and spontaneously activated neutrophils, potentially contribute to tissue damage in NEMO deficiency.

Expanding the Clinical and Immunological Phenotypes and Natural History of MALT1 Deficiency.

PURPOSE: MALT1 deficiency is a combined immune deficiency characterized by recurrent infections, eczema, chronic diarrhea, and failure to thrive. Clinical and immunological characterizations of the disease have not been previously reported in large cohorts. We sought to determine the clinical, immunological, genetic features, and the natural history of MALT-1 deficiency. METHODS: The clinical findings and treatment outcomes were evaluated in nine new MALT1-deficient patients. Peripheral lymphocyte subset analyses, cytokine secretion, and proliferation assays were performed. We also analyzed ten previously reported patients to comprehensively evaluate genotype/phenotype correlation. RESULTS: The mean age of patients and disease onset were 33 ± 17 and 1.6 ± 0.7 months, respectively. The main clinical findings of the disease were recurrent infections (100%), skin involvement (100%), failure to thrive (100%), oral lesions (67%), chronic diarrhea (56%), and autoimmunity (44%). Eosinophilia and high IgE were observed in six (67%) and two (22%) patients, respectively. The majority of patients had normal T and NK cells, while eight (89%) exhibited reduced B cells. Immunoglobulin replacement and antibiotics prophylaxis were mostly ineffective in reducing the frequency of infections and other complications. One patient received hematopoietic stem cell transplantation (HSCT) and five patients died as a complication of life-threatening infections. Analyzing this cohort with reported patients revealed overall survival in 58% (11/19), which was higher in patients who underwent HSCT (P = 0.03). CONCLUSION: This cohort provides the largest analysis for clinical and immunological features of MALT1 deficiency. HSCT should be offered as a curative therapeutic option for all patients at the early stage of life.

Primary antibody deficiencies in Turkey: molecular and clinical aspects.

Primary antibody deficiencies (PAD) are the most common subtype of primary immunodeficiencies, characterized by increased susceptibility to infections and autoimmunity, allergy, or malignancy predisposition. PAD syndromes comprise of immune system genes highlighted the key role of B cell activation, proliferation, migration, somatic hypermutation, or isotype switching have a wide spectrum from agammaglobulinemia to selective Ig deficiency. In this study, we describe the molecular and the clinical aspects of fifty-two PAD patients. The most common symptoms of our cohort were upper and lower respiratory infections, bronchiectasis, diarrhea, and recurrent fever. Almost all patients (98%) had at least one of the symptoms like autoimmunity, lymphoproliferation, allergy, or gastrointestinal disease. A custom-made next-generation sequencing (NGS) panel, which contains 24 genes, was designed to identify well-known disease-causing variants in our cohort. We identified eight variants (15.4%) among 52 PAD patients. The variants mapped to BTK (n = 4), CD40L (n = 1), ICOS (n = 1), IGHM (n = 1), and TCF3 (n = 1) genes. Three novel variants were described in the BTK (p.G414W), ICOS (p.G60*), and IGHM (p.S19*) genes. We performed Sanger sequencing to validate pathogenic variants and check for allelic segregation in the family. Targeted NGS panel sequencing can be beneficial as a suitable diagnostic modality for diagnosing well-known monogenic PAD diseases (only 2-10% of PADs); however, screening only the coding regions of the genome may not be adequately powered to solve the pathogenesis of PAD in all cases. Deciphering the regulatory regions of the genome and better understanding the epigenetic modifications will elucidate the molecular basis of complex PADs.

Evolution and long-term outcomes of combined immunodeficiency due to CARMIL2 deficiency.

BACKGROUND: Biallelic loss-of-function mutations in CARMIL2 cause combined immunodeficiency associated with dermatitis, inflammatory bowel disease (IBD), and EBV-related smooth muscle tumors. Clinical and immunological characterizations of the disease with long-term follow-up and treatment options have not been previously reported in large cohorts. We sought to determine the clinical and immunological features of CARMIL2 deficiency and long-term efficacy of treatment in controlling different disease manifestations. METHODS: The presenting phenotypes, long-term outcomes, and treatment responses were evaluated prospectively in 15 CARMIL2-deficient patients, including 13 novel cases. Lymphocyte subpopulations, protein expression, regulatory T (Treg), and circulating T follicular helper (cTFH ) cells were analyzed. Three-dimensional (3D) migration assay was performed to determine T-cell shape. RESULTS: Mean age at disease onset was 38 ± 23 months. Main clinical features were skin manifestations (n = 14, 93%), failure to thrive (n = 10, 67%), recurrent infections (n = 10, 67%), allergic symptoms (n = 8, 53%), chronic diarrhea (n = 4, 27%), and EBV-related leiomyoma (n = 2, 13%). Skin manifestations ranged from atopic and seborrheic dermatitis to psoriasiform rash. Patients had reduced proportions of memory CD4+ T cells, Treg, and cTFH cells. Memory B and NK cells were also decreased. CARMIL2-deficient T cells exhibited reduced T-cell proliferation and cytokine production following CD28 co-stimulation and normal morphology when migrating in a high-density 3D collagen gel matrix. IBD was the most severe clinical manifestation, leading to growth retardation, requiring multiple interventional treatments. All patients were alive with a median follow-up of 10.8 years (range: 3-17 years). CONCLUSION: This cohort provides clinical and immunological features and long-term follow-up of different manifestations of CARMIL2 deficiency.

Congenital iRHOM2 deficiency causes ADAM17 dysfunction and environmentally directed immunodysregulatory disease.

We report a pleiotropic disease due to loss-of-function mutations in RHBDF2, the gene encoding iRHOM2, in two kindreds with recurrent infections in different organs. One patient had recurrent pneumonia but no colon involvement, another had recurrent infectious hemorrhagic colitis but no lung involvement and the other two experienced recurrent respiratory infections. Loss of iRHOM2, a rhomboid superfamily member that regulates the ADAM17 metalloproteinase, caused defective ADAM17-dependent cleavage and release of cytokines, including tumor-necrosis factor and amphiregulin. To understand the diverse clinical phenotypes, we challenged Rhbdf2-/- mice with Pseudomonas aeruginosa by nasal gavage and observed more severe pneumonia, whereas infection with Citrobacter rodentium caused worse inflammatory colitis than in wild-type mice. The fecal microbiota in the colitis patient had characteristic oral species that can predispose to colitis. Thus, a human immunodeficiency arising from iRHOM2 deficiency causes divergent disease phenotypes that can involve the local microbial environment.

Impaired respiratory burst contributes to infections in PKCδ-deficient patients.

Patients with autosomal recessive protein kinase C δ (PKCδ) deficiency suffer from childhood-onset autoimmunity, including systemic lupus erythematosus. They also suffer from recurrent infections that overlap with those seen in patients with chronic granulomatous disease (CGD), a disease caused by defects of the phagocyte NADPH oxidase and a lack of reactive oxygen species (ROS) production. We studied an international cohort of 17 PKCδ-deficient patients and found that their EBV-B cells and monocyte-derived phagocytes produced only small amounts of ROS and did not phosphorylate p40phox normally after PMA or opsonized Staphylococcus aureus stimulation. Moreover, the patients' circulating phagocytes displayed abnormally low levels of ROS production and markedly reduced neutrophil extracellular trap formation, altogether suggesting a role for PKCδ in activation of the NADPH oxidase complex. Our findings thus show that patients with PKCδ deficiency have impaired NADPH oxidase activity in various myeloid subsets, which may contribute to their CGD-like infectious phenotype.

Mesenchymal stem cells derived from human dental follicle modulate the aberrant immune response in atopic dermatitis.

Background: Atopic dermatitis (AD) is an inflammatory cutaneous disorder. The advancements in the understanding of AD immunological pathogenesis have caused the development of therapies that suppress the dysregulated immune response. We aimed to evaluate the immunomodulatory effect of dental stem cells (dental follicle-mesenchymal stem cells [DF-MSCs]) on AD patients. Materials & methods: We investigated the immunoregulatory potential of DF-MSCs on T cell response in AD and compared them with psoriasis and healthy individuals and the underlying mechanisms. Results: DF-MSCs significantly reduced Fas, FasL and TNFR II frequency in T cells, increased naive T cell population while reducing memory T cell, decreased inflammatory cytokine levels and promoted Tregs frequency in the AD population. Conclusion: These results imply that DF-MSCs are modulating inflammation through decreasing T cell apoptosis, inducing Treg expansion and stabilizing cytokine levels.

Lay abstract Background: Atopic dermatitis (AD) is an inflammatory cutaneous disorder characterized by immune-mediated inflammation and epidermal barrier dysfunction. There is no definite solution for the treatment of AD. We aimed to evaluate the immunomodulatory and immunosuppressive effect of dental stem cells (dental follicle-mesenchymal stem cell [DF-MSCs]) on AD. Materials & methods: We investigated the immunoregulatory potential of DF-MSCs on inflammatory response in AD and compared them with psoriasis and healthy individuals and the mechanism underlying it. Results: DF-MSCs significantly reduced apoptosis-related markers in immune cells, decreased inflammatory cytokine levels and promoted Treg frequency in the AD. Conclusion: Our findings provide basic evidence for the potential role of DF-MSCs as a cellular therapy option in the treatment of AD and shed light on future clinical studies.