Functional Selectivity in Cytokine Signaling Revealed Through a Pathogenic EPO Mutation.

Cytokines are classically thought to stimulate downstream signaling pathways through monotonic activation of receptors. We describe a severe anemia resulting from a homozygous mutation (R150Q) in the cytokine erythropoietin (EPO). Surprisingly, the EPO R150Q mutant shows only a mild reduction in affinity for its receptor but has altered binding kinetics. The EPO mutant is less effective at stimulating erythroid cell proliferation and differentiation, even at maximally potent concentrations. While the EPO mutant can stimulate effectors such as STAT5 to a similar extent as the wild-type ligand, there is reduced JAK2-mediated phosphorylation of select downstream targets. This impairment in downstream signaling mechanistically arises from altered receptor dimerization dynamics due to extracellular binding changes. These results demonstrate how variation in a single cytokine can lead to biased downstream signaling and can thereby cause human disease. Moreover, we have defined a distinct treatable form of anemia through mutation identification and functional studies.

Outcomes of HLA-mismatched HSCT with TCRαß/CD19 depletion or post-HSCT cyclophosphamide for inborn errors of immunity.

HLA-mismatched transplants with either in vitro depletion of CD3+TCRαß/CD19 (TCRαß) cells or in vivo T-cell depletion using post-transplant cyclophosphamide (PTCY) have been increasingly used for patients with inborn errors of immunity (IEI). We performed a retrospective multicenter study via the EBMT registry on 306 children with IEI undergoing first transplant between 2010-2019 from an HLA-mismatched donor using TCRαß (n=167) or PTCY (n=139). Median age at HSCT was 1.2 years (range, 0.03-19.6 years). The 3-year overall survival (OS) was 78% (95% confidence interval (CI), 71-84%) after TCRαß and 66% (57-74%) after PTCY (p=0.013). Pre-HSCT morbidity score (hazard ratio (HR) 2.27, 1.07-4.80, p=0.032) and non-Busulfan/Treosulfan conditioning (HR 3.12, 1.98-4.92, p<0.001) were the only independent predictors of unfavorable OS. The 3-year event-free survival (EFS) was 58% (50-66%) after TCRαß and 57% (48-66%) after PTCY (p=0.804). Cumulative incidence of severe acute GvHD was higher after PTCY (15%, 9-21%) than TCRαß (6%, 2-9%, p=0.007), with no difference in chronic GvHD (PTCY, 11%, 6-17%; TCRαß, 7%, 3-11%, p=0.173). The 3-year GvHD-free EFS was 53% (44-61%) after TCRαß and 41% (32-50%) after PTCY (p=0.080). PTCY had significantly higher rates of veno-occlusive disease (14.4% versus TCRαß 4.9%, p=0.009), acute kidney injury (12.7% versus 4.6%, p=0.032) and pulmonary complications (38.2% versus 24.1%, p=0.017). Adenoviraemia (18.3% versus PTCY 8.0%, p=0.015), primary graft failure (10%, versus 5%, p=0.048), and second HSCT (17.4% versus 7.9%, p=0.023) were significantly higher in TCRαß. In conclusion, this study demonstrates that both approaches are suitable options in IEI patients, although characterized by different advantages and outcomes.

Pyruvate kinase deficiency in 29 Turkish patients with two novel intronic variants.

Pyruvate kinase (PK) is a key enzyme of anaerobic glycolysis. The genetic heterogeneity of PK deficiency (PKD) is high, and over 400 unique variants have been identified. Twenty-nine patients who had been diagnosed as PKD genetically in seven distinct paediatric haematology departments were evaluated. Fifteen of 23 patients (65.2%) had low PK levels. The PK:hexokinase ratio had 100% sensitivity for PKD diagnosis, superior to PK enzyme assay. Two novel intronic variants (c.695-1G>A and c.694+43C>T) have been described. PKD should be suspected in patients with chronic non-spherocytic haemolytic anaemia, even if enzyme levels are falsely normal. Total PKLR gene sequencing is necessary for the characterization of patients with PKD and for genetic counselling.

COVID-19 disease in children and adolescents following allogeneic hematopoietic stem cell transplantation: A report from the Turkish pediatric bone marrow transplantation study group.

BACKGROUND: Data on the risk factors and outcomes for pediatric patients with SARS-CoV-2 infection (COVID-19) following hematopoietic stem cell transplantation (HSCT) are limited. OBJECTIVES: The study aimed to analyze the clinical signs, risk factors, and outcomes for ICU admission and mortality in a large pediatric cohort who underwent allogeneic HSCT prior to COVID-19 infection. METHOD: In this nationwide study, we retrospectively reviewed the data of 184 pediatric HSCT recipients who had COVID-19 between March 2020 and August 2022. RESULTS: The median time from HSCT to COVID-19 infection was 209.0 days (IQR, 111.7-340.8; range, 0-3845 days). The most common clinical manifestation was fever (58.7%). While most patients (78.8%) had asymptomatic/mild disease, the disease severity was moderate in 9.2% and severe and critical in 4.4% and 7.6%, respectively. The overall mortality was 10.9% (n: 20). Deaths were attributable to COVID-19 in nine (4.9%) patients. Multivariate analysis revealed that lower respiratory tract disease (LRTD) (OR, 23.20, p: .001) and lymphopenia at diagnosis (OR, 5.21, p: .006) were risk factors for ICU admission and that HSCT from a mismatched donor (OR, 54.04, p: .028), multisystem inflammatory syndrome in children (MIS-C) (OR, 31.07, p: .003), and LRTD (OR, 10.11, p: .035) were associated with a higher risk for COVID-19-related mortality. CONCLUSION: While COVID-19 is mostly asymptomatic or mild in pediatric transplant recipients, it can cause ICU admission in those with LRTD or lymphopenia at diagnosis and may be more fatal in those who are transplanted from a mismatched donor and those who develop MIS-C or LRTD.

Immunodeficiency associated with a novel functionally defective variant of SLC19A1 benefits from folinic acid treatment.

Insufficient dietary folate intake, hereditary malabsorption, or defects in folate transport may lead to combined immunodeficiency (CID). Although loss of function mutations in the major intestinal folate transporter PCFT/SLC46A1 was shown to be associated with CID, the evidence for pathogenic variants of RFC/SLC19A1 resulting in immunodeficiency was lacking. We report two cousins carrying a homozygous pathogenic variant c.1042 G > A, resulting in p.G348R substitution who showed symptoms of immunodeficiency associated with defects of folate transport. SLC19A1 expression by peripheral blood mononuclear cells (PBMC) was quantified by real-time qPCR and immunostaining. T cell proliferation, methotrexate resistance, NK cell cytotoxicity, Treg cells and cytokine production by T cells were examined by flow cytometric assays. Patients were treated with and benefited from folinic acid. Studies revealed normal NK cell cytotoxicity, Treg cell counts, and naive-memory T cell percentages. Although SLC19A1 mRNA and protein expression were unaltered, remarkably, mitogen induced-T cell proliferation was significantly reduced at suboptimal folic acid and supraoptimal folinic acid concentrations. In addition, patients' PBMCs were resistant to methotrexate-induced apoptosis supporting a functionally defective SLC19A1. This study presents the second pathogenic SLC19A1 variant in the literature, providing the first experimental evidence that functionally defective variants of SLC19A1 may present with symptoms of immunodeficiency.

Defective Treg generation and increased type 3 immune response in leukocyte adhesion deficiency 1.

In 15 Turkish LAD-1 patients and controls, we assessed the impact of pathogenic ITGB2 mutations on Th17/Treg differentiation and functions, and innate lymphoid cell (ILC) subsets. The percentage of peripheral blood Treg cells, in vitro-generated induced Tregs differentiated from naive CD4+ T cells were decreased despite the elevated absolute counts of CD4+ cells in LAD-1 patients. Serum IL-23 levels were elevated in LAD-1 patients. Post-curdlan stimulation, LAD-1 patient-derived PBMCs produced more IL-17A. Additionally, the percentages of CD18-deficient Th17 cells expanded from total or naïve CD4+ T cells were higher. The blood ILC3 subset was significantly elevated in LAD-1. Finally, LAD-1 PBMCs showed defects in trans-well migration and proliferation and were more resistant to apoptosis. Defects in de novo generation of Tregs from CD18-deficient naïve T cells and elevated Th17s, and ILC3s in LAD-1 patients' peripheral blood suggest a type 3-skewed immunity and may contribute to LAD-1-associated autoimmune symptoms.

The Resilience Scale for Parents of Children with Cancer: Scale development and psychometric evaluation.

OBJECTIVE: This study aimed to develop a Resilience Scale for Parents of Children with Cancer (RSP-CC) designed specifically for parents of children with cancer and to evaluate its psychometric properties. METHODS: Based on the Resilience Model for Families of Children with Cancer, items were created after an extensive literature review and evaluated through expert consultation and a pilot study. Psychometric evaluation was conducted with the parents of 601 children with cancer in the pediatric hematology oncology services of different hospitals in the Ankara and Kayseri provinces in Turkey. RESULTS: A 4-factor structure was illustrated by exploratory factor analysis and confirmed by confirmatory factor analysis, explaining 62.192% of the total variance. In the reliability analysis of the scale, Interclass correlation = 0.993 and Cronbach's alpha = 0.994 were found for the scale. Robust correlation coefficients were found between test-retest, and the correlation between the two measurements was statistically significant (r = 0.990; p Ë‚ 0.001). As a result, the validity of a 24-item scale structure consisting of 4 dimensions was validated. CONCLUSIONS: It may be said that the RSP-CC meets the necessary criteria to examine the resilience in parents of children aged 0-18 with a cancer diagnosis, and its psychometric properties are reasonable sufficient.

Aceruloplasminemia presenting with microcytic anemia in a Turkish boy due to a novel pathogenic variant.

Aceruloplasminemia inherited autosomal recessively in the ceruloplasmin gene is a progressive disease with iron accumulation in various organs such as the brain, liver, pancreas, and retina. Ceruloplasmin gene encodes ceruloplasmin protein, which has ferroxidase activity and is involved in copper and iron metabolism. Progressive neurotoxicity, retinopathy, and diabetes may develop in about 40-60 decades. In addition, microcytic anemia accompanied by high ferritin and low ceruloplasmin level that develop at earlier ages can be first manifestation. Iron chelation may be utilized in the treatment to reduce the toxicity. Early diagnosis and treatment may delay the onset of symptoms. A 14-year-old male patient was followed up with microcytic anemia since an eight-years old. Anemia was accompanied by microcytosis, high ferritin, and low copper and ceruloplasmin levels. A novel homozygous c.690delG variant was detected in ceruloplasmin by whole exome sequencing. Clinical, laboratory and imaging findings of the patient demonstrated aceruloplasminemia. We present a boy with persistent microcytic anemia of the first manifestation at the age of eight, as the youngest case of aceruloplasminemia in the literature. Thereby, aceruloplasminemia should be kept in mind in the etiology of microcytic anemia whose cause couldn't found in childhood.

International retrospective study of allogeneic hematopoietic cell transplantation for activated PI3K-delta syndrome.

BACKGROUND: Activated phosphoinositide 3-kinase delta syndrome (APDS) is a combined immunodeficiency with a heterogeneous phenotype considered reversible by allogeneic hematopoietic cell transplantation (HCT). OBJECTIVES: This study sought to characterize HCT outcomes in APDS. METHODS: Retrospective data were collected on 57 patients with APDS1/2 (median age, 13 years; range, 2-66 years) who underwent HCT. RESULTS: Pre-HCT comorbidities such as lung, gastrointestinal, and liver pathology were common, with hematologic malignancy in 26%. With median follow-up of 2.3 years, 2-year overall and graft failure-free survival probabilities were 86% and 68%, respectively, and did not differ significantly by APDS1 versus APDS2, donor type, or conditioning intensity. The 2-year cumulative incidence of graft failure following first HCT was 17% overall but 42% if mammalian target of rapamycin inhibitor(s) (mTORi) were used in the first year post-HCT, compared with 9% without mTORi. Similarly, 2-year cumulative incidence of unplanned donor cell infusion was overall 28%, but 65% in the context of mTORi receipt and 23% without. Phenotype reversal occurred in 96% of evaluable patients, of whom 17% had mixed chimerism. Vulnerability to renal complications continued post-HCT, adding new insights into potential nonimmunologic roles of phosphoinositide 3-kinase not correctable through HCT. CONCLUSIONS: Graft failure, graft instability, and poor graft function requiring unplanned donor cell infusion were major barriers to successful HCT. Post-HCT mTORi use may confer an advantage to residual host cells, promoting graft instability. Longer-term post-HCT follow-up of more patients is needed to elucidate the kinetics of immune reconstitution and donor chimerism, establish approaches that reduce graft instability, and assess the completeness of phenotype reversal over time.

Hematopoietic cell transplantation in chronic granulomatous disease: a study of 712 children and adults.

Chronic granulomatous disease (CGD) is a primary immunodeficiency resulting in life-threatening infections and inflammatory complications. Allogeneic hematopoietic cell transplantation (allo-HCT) can cure the disease, but the indication to transplant remains controversial. We performed a retrospective multicenter study of 712 patients with CGD who underwent allo-HCT transplantation from March 1993 through December 2018. We studied 635 children (aged <18 years) and 77 adults. Median follow-up was 45 months. Median age at transplantation was 7 years (range, 0.1-48.6). Kaplan-Meier estimates of overall survival (OS) and event-free survival (EFS) at 3 years were 85.7% and 75.8%, respectively. In multivariate analysis, older age was associated with reduced survival and increased chronic graft-versus-host disease. Nevertheless, OS and EFS at 3 years for patients ≥18 years were 76% and 69%, respectively. Use of 1-antigen-mismatched donors was associated with reduced OS and EFS . No significant difference was found in OS, but a significantly reduced EFS was noted in the small group of patients who received a transplant from a donor with a >1 antigen mismatch. Choice of conditioning regimen did not influence OS or EFS. In summary, we report an excellent outcome after allo-HCT in CGD, with low incidence of graft failure and mortality in all ages. Older patients and recipients of 1-antigen-mismatched grafts had a less favorable outcome. Transplantation should be strongly considered at a younger age and particularly in the presence of a well-matched donor.

Extended clinical and immunological phenotype and transplant outcome in CD27 and CD70 deficiency.

Biallelic mutations in the genes encoding CD27 or its ligand CD70 underlie inborn errors of immunity (IEIs) characterized predominantly by Epstein-Barr virus (EBV)-associated immune dysregulation, such as chronic viremia, severe infectious mononucleosis, hemophagocytic lymphohistiocytosis (HLH), lymphoproliferation, and malignancy. A comprehensive understanding of the natural history, immune characteristics, and transplant outcomes has remained elusive. Here, in a multi-institutional global collaboration, we collected the clinical information of 49 patients from 29 families (CD27, n = 33; CD70, n = 16), including 24 previously unreported individuals and identified a total of 16 distinct mutations in CD27, and 8 in CD70, respectively. The majority of patients (90%) were EBV+ at diagnosis, but only ∼30% presented with infectious mononucleosis. Lymphoproliferation and lymphoma were the main clinical manifestations (70% and 43%, respectively), and 9 of the CD27-deficient patients developed HLH. Twenty-one patients (43%) developed autoinflammatory features including uveitis, arthritis, and periodic fever. Detailed immunological characterization revealed aberrant generation of memory B and T cells, including a paucity of EBV-specific T cells, and impaired effector function of CD8+ T cells, thereby providing mechanistic insight into cellular defects underpinning the clinical features of disrupted CD27/CD70 signaling. Nineteen patients underwent allogeneic hematopoietic stem cell transplantation (HSCT) prior to adulthood predominantly because of lymphoma, with 95% survival without disease recurrence. Our data highlight the marked predisposition to lymphoma of both CD27- and CD70-deficient patients. The excellent outcome after HSCT supports the timely implementation of this treatment modality particularly in patients presenting with malignant transformation to lymphoma.

Therapeutic effects of vitamin D and IL-22 on methotrexate-induced mucositis in mice.

Mucositis is a common side effect of cancer therapies and transplant conditioning regimens. Management of mucositis involves multiple approaches from oral hygiene, anti-inflammatory, anti-apoptotic, cytoprotective, and antioxidant agents, to cryo-therapy, physical therapy, and growth factors. There is room for novel, affordable treatment options, or improvement of currently available therapies. Vitamin D has been shown to regulate mucosa-resident cell populations such as Th17 or innate lymphoid cells and critical mucosal cytokine IL-22; however, their therapeutic potential has not been put to test in preclinical mouse models. In this study, we aimed to test the therapeutic potential of vitamin D injections and IL-22 overexpression in a murine model of chemotherapy-induced mucositis. Balb/c mice were given daily intraperitoneal injections of vitamin D. Mucositis was induced by methotrexate. Another group received IL-22 plasmid via hydrodynamic gene delivery. Weight loss and intestinal histopathology, intestinal levels of cytokines IL-22, IL-17A, GM-CSF, IL-23, IFN-γ, TNF-α, and IL-10, and number of intestinal lamina propria B cell, neutrophil, and total innate lymphoid cells were quantified. Daily vitamin D injections ameliorated intestinal inflammation and elevated intestinal IL-22 levels compared with control groups. Temporal overexpression of IL-22 by hydrodynamic gene delivery slightly increased intestinal IL-22 but failed to confer significant protection from mucositis. To our knowledge, this is the first experimental demonstration in an animal model of mucositis of therapeutic use of vitamin D and IL-22 supplementation and our results with vitamin D suggest it may have merit in further trials in human mucositis patients.

Assessment of extracorporeal photopheresis related cell damage.

AIM: Extracorporeal photochemotherapy (ECP) is emphasized chiefly as it has a high safety profile. However, the genotoxic effects of ECP are not known. This experimental study aimed to assess the potential genotoxic impact of ECP treatment by the AKLIDES system, a new generation standardized and automated evaluation method. MATERIALS AND METHODS: Buffy coats were obtained from the blood of 26 healthy volunteers, and ECP was applied to 2 j/cm2 UV-A for two hours. After the DNA isolation procedure, all slides were stained with DAPI to visualize lymphocytes, FITC for visualization of damage foci marker (γH2AX), and APC for visualization of repair foci marker (53BP1). With the AKLIDES imaging system, all parameters were evaluated. RESULTS: Median damage marker Foci γ-H2AX before and after ECP were 11.42 and 18.65 arbitrary units, respectively (p = 0.153). Median repair marker foci 53BP1 (repair biomarker) before and after ECP were measured as 4.17 and 6.7 arbitrary units. The difference was also not statistically significant (p = 0.088). Although 58 % of cells were affected by ECP irradiation, as shown by FITC fluorescent staining, no statistical difference was found in any genotoxicity parameters. CONCLUSION: We found an increase in the foci γ-H2AX parameter, one of the objective indicators of DNA breaks, and an increase in the foci 53BP1 parameter, which indicates the post-damage repair mechanisms after ECP. However, further in vitro, and in vivo studies are needed with large sample volumes to demonstrate the significance.

Social exclusion and behavior problems in adolescents with cancer and healthy counterparts.

PURPOSE: This cross-sectional study was conducted to determine social exclusion, internalized and externalized behavioral problems in adolescents with cancer and to compare them with healthy counterparts. DESIGN AND METHODS: The sample consisted of adolescents age 10-19 years (N = 70) followed up in the hemato-oncology outpatient clinic of a tertiary hospital and healthy adolescents age 10-19 years (N = 92) who were studying in secondary and high schools. The data were collected with a questionnaire for adolescents with cancer and healthy adolescents, The Ostracism Experience Scale for Adolescents (OES-A), Youth Externalizing Behavior Screener (YEBS), and Youth Internalizing Problems Screener (YIPS). RESULTS: The OES-A mean scores of cancer and healthy adolescents in the study were 35.68 ± 9.38 and 27.64 ± 5.35 (p ≤ 0.001), the YEBS mean scores were 23.51 ± 4.88 and 20.52 ± 5.42 (p ≤ 0.001), and the YIPS mean scores were 21.72 ± 6.48 and 19.18 ± 7.60 (p = 0.007), respectively. There was a low-level positive correlation between the mean scores of the OES-A and YEBS (r = 0.345, p < 0.05) and mean scores of the YEBS and YIPS (r = 0.308, p < 0.05) of adolescents with cancer. CONCLUSIONS: Adolescents with cancer had higher scores on social exclusion, internalized and externalized behavioral problems than healthy counterparts in the current study. PRACTICE IMPLICATIONS: The current study should lead pediatric oncology nurses to be more aware of social exclusion and internalized and externalized behavioral problems in adolescents with cancer after clinical treatment, and to provide appropriate psycho-oncological care.

Seasonal Human Coronavirus Respiratory Tract Infection in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: Little is known about characteristics of seasonal human coronaviruses (HCoVs) (NL63, 229E, OC43, and HKU1) after allogeneic stem cell transplantation (allo-HSCT). METHODS: This was a collaborative Spanish and European bone marrow transplantation retrospective multicenter study, which included allo-HSCT recipients (adults and children) with upper respiratory tract disease (URTD) and/or lower respiratory tract disease (LRTD) caused by seasonal HCoV diagnosed through multiplex polymerase chain reaction assays from January 2012 to January 2019. RESULTS: We included 402 allo-HSCT recipients who developed 449 HCoV URTD/LRTD episodes. Median age of recipients was 46 years (range, 0.3-73.8 years). HCoV episodes were diagnosed at a median of 222 days after transplantation. The most common HCoV subtype was OC43 (n = 170 [38%]). LRTD involvement occurred in 121 episodes (27%). HCoV infection frequently required hospitalization (18%), oxygen administration (13%), and intensive care unit (ICU) admission (3%). Three-month overall mortality after HCoV detection was 7% in the whole cohort and 16% in those with LRTD. We identified 3 conditions associated with higher mortality in recipients with LRTD: absolute lymphocyte count <0.1 × 109/mL, corticosteroid use, and ICU admission (hazard ratios: 10.8, 4.68, and 8.22, respectively; P < .01). CONCLUSIONS: Seasonal HCoV after allo-HSCT may involve LRTD in many instances, leading to a significant morbidity.

CD137 deficiency causes immune dysregulation with predisposition to lymphomagenesis.

Dysregulated immune responses are essential underlying causes of a plethora of pathologies including cancer, autoimmunity, and immunodeficiency. We here investigated 4 patients from unrelated families presenting with immunodeficiency, autoimmunity, and malignancy. We identified 4 distinct homozygous mutations in TNFRSF9 encoding the tumor necrosis factor receptor superfamily member CD137/4-1BB, leading to reduced, or loss of, protein expression. Lymphocytic responses crucial for immune surveillance, including activation, proliferation, and differentiation, were impaired. Genetic reconstitution of CD137 reversed these defects. CD137 deficiency is a novel inborn error of human immunity characterized by lymphocytic defects with early-onset Epstein-Barr virus (EBV)-associated lymphoma. Our findings elucidate a functional role and relevance of CD137 in human immune homeostasis and antitumor responses.

Prognostic factors for survival in children who relapsed after allogeneic hematopoietic stem cell transplantation for acute leukemia.

BACKGROUND: Post-transplant relapse has a dismal prognosis in children with acute leukemia undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Data on risk factors, treatment options, and outcomes are limited. PROCEDURE: In this retrospective multicenter study in which a questionnaire was sent to all pediatric transplant centers reporting relapse after allo-HSCT for a cohort of 938 children with acute leukemia, we analyzed 255 children with relapse of acute leukemia after their first allo-HSCT. RESULTS: The median interval from transplantation to relapse was 180 days, and the median follow-up from relapse to the last follow-up was 1844 days. The 3-year overall survival (OS) rate was 12.0%. The main cause of death was disease progression or subsequent relapse (82.6%). The majority of children received salvage treatment with curative intent without a second HSCT (67.8%), 22.0% of children underwent a second allo-HSCT, and 10.2% received palliative therapy. Isolated extramedullary relapse (hazard ratio (HR): 0.607, P = .011) and relapse earlier than 365 days post-transplantation (HR: 2.101, P < .001 for 0-180 days; HR: 1.522, P = .041 for 181-365 days) were found in multivariate analysis to be significant prognostic factors for outcome. The type of salvage therapy in chemosensitive relapse was identified as a significant prognostic factor for OS. CONCLUSION: A salvage approach with curative intent may be considered for patients with post-transplant relapse, even if they relapse in the first year post-transplantation. For sustainable remission, a second allo-HSCT may be recommended for patients who achieve complete remission after reinduction treatment.

Common Variable Immunodeficiency, Autoimmune Hemolytic Anemia, and Pancytopenia Associated With a Defect in IKAROS.

OBJECTIVE: Mutations in IKZF1, which encodes Ikaros family zinc finger 1 (IKAROS) transcription factor, are associated with recurrent infections, cytopenia, autoimmune diseases, and hematologic malignancies. Diverse clinical phenotypes resulting from IKZF1 mutations include pulmonary fungal infections, cytopenia, autoimmune hemolytic anemia (AIHA), and malignancies. In this study, we aimed to assess the DNA-binding ability and pericentromeric (PC) localization of a variant of IKZF discovered in a patient. MATERIALS AND METHODS: DNA-binding ability of a pathogenic IKZF variant was tested using electrophoretic mobility shift assay and PC localization of the variant was assessed by immunofluorescent microscopy in NIH3T3 cells. RESULTS: Clinical features of a 3-month-old male infant who underwent hematopoietic stem cell transplantation because of an IKZF1 mutation-associated common variable immunodeficiency, AIHA, and pancytopenia are described. DNA studies revealed a heterozygous missense variant (IKZF1 NM_006060 c.427C>T; p.R143W). Cotransfection studies revealed that mutant R143W has a partial dominant-negative effect over PC targeting and DNA binding. CONCLUSIONS: IKZF1 mutation must be kept in mind if neonatal AIHA, common variable immunodeficiency, and pancytopenia are observed.

ILC3 deficiency and generalized ILC abnormalities in DOCK8-deficient patients.

BACKGROUND: Dedicator of cytokinesis 8 (DOCK8) deficiency is the main cause of the autosomal recessive hyper-IgE syndrome (HIES). We previously reported the selective loss of group 3 innate lymphoid cell (ILC) number and function in a Dock8-deficient mouse model. In this study, we sought to test whether DOCK8 is required for the function and maintenance of ILC subsets in humans. METHODS: Peripheral blood ILC1-3 subsets of 16 DOCK8-deficient patients recruited at the pretransplant stage, and seven patients with autosomal dominant (AD) HIES due to STAT3 mutations, were compared with those of healthy controls or post-transplant DOCK8-deficient patients (n = 12) by flow cytometry and real-time qPCR. Sorted total ILCs from DOCK8- or STAT3-mutant patients and healthy controls were assayed for survival, apoptosis, proliferation, and activation by IL-7, IL-23, and IL-12 by cell culture, flow cytometry, and phospho-flow assays. RESULTS: DOCK8-deficient but not STAT3-mutant patients exhibited a profound depletion of ILC3s, and to a lesser extent ILC2s, in their peripheral blood. DOCK8-deficient ILC1-3 subsets had defective proliferation, expressed lower levels of IL-7R, responded less to IL-7, IL-12, or IL-23 cytokines, and were more prone to apoptosis compared with those of healthy controls. CONCLUSION: DOCK8 regulates human ILC3 expansion and survival, and more globally ILC cytokine signaling and proliferation. DOCK8 deficiency leads to loss of ILC3 from peripheral blood. ILC3 deficiency may contribute to the susceptibility of DOCK8-deficient patients to infections.

A Rare Case of Activated Phosphoinositide 3-Kinase Delta Syndrome (APDS) Presenting With Hemophagocytosis Complicated With Hodgkin Lymphoma.

Gain of function mutations in the p110δ catalytic subunit of the phosphatidylinositol-3-OH kinase (PIK3CD) classified as activated phosphoinositide 3-kinase delta syndrome (APDS) are the cause of a primary immunodeficiency characterized by recurrent sinopulmonary infections, and lymphoproliferation. Previously, autoimmunity and Epstein-Barr virus-related B-cell lymphoma have been documented for patients with APDS; here, we present a case that extends the picture, as the patient shows the full diagnostic criteria of hemophagocytic lymphohistiocytosis at 6 months of age. He experienced Hodgkin lymphoma as a 2.5-year-old baby. Next-generation sequencing returned a de novo heterozygous missense variant in PIK3CD (LRG_191t1: c.3061G>A; p.Glu1021Lys), confirming the primary immunodeficiency. After 2 courses of ifosfamide, cisplatin, and etoposide combined with brentuximab, the patient successfully underwent allogeneic hematopoietic stem cell transplantation from his HLA full matched sister, and he has been well for 18 months after that. The hematologist treating Hodgkin lymphoma and/or hemophagocytic lymphohistiocytosis should be vigilant about the possible underlying immune deficiency, and they should consider APDS in their differential diagnosis.