TXB-001, a newly-developed polymer-conjugated anthracycline: Significantly lower adverse effects in animal models of alopecia and hand-foot syndrome.

Anthracycline anti-cancer drugs have been widely used in the treatment of several cancers; however, their use is limited by adverse effects (AEs). Alopecia is a common AE that is minimally invasive, but adversely affects mental health and reduces quality of life (QoL). Hand-foot syndrome (HFS) is a dose-limiting AE of DOXIL, a liposomal formulation of doxorubicin (DOX). Although it is not a life-threatening condition, HFS affects function and reduces QoL. TXB-001 is a new candidate polymer-conjugated anthracycline anti-cancer drug, and modified and optimized polymerized pirarubicin (THP), known as P-THP, is expected to have low toxicity and high efficacy. The anti-cancer effects of TXB-001 were examined using the 4T1 mouse model. An alopecia mouse model and HFS rat model were used to evaluate the alopecia- and HFS-inducing effects of TXB-001 and compare their severity with existing anthracycline anti-cancer drugs. A pharmacokinetic analysis of plasma as well as chest, palmar, and plantar skin samples after the single intravenous administration of DOXIL and TXB-001 to rats was also performed. The results obtained revealed that TXB-001 exerted similar anti-cancer effects to those of DOXIL in mice, weaker alopecia-inducing effects than DOX, DOXIL, and THP in mice, and no or markedly weaker HFS-like changes than DOXIL, which induced significant histopathological changes. The results of the pharmacokinetic analysis showed the accumulation of DOXIL, but not TXB-001, in skin, particularly palmar and plantar skin samples, and these differences were considered to contribute to their HFS-inducing effects.

Helix-to-Disc Conversion of Thia[6]helicenes into Coronenes Facilitated by Sulfur Oxidation and Fluorination.

Helicenes, with their unique helical structures, have long captured the interest of synthetic chemists, not only as end products, but also as versatile platforms for further chemical transformations. However, transforming [6]helicene into planar coronene typically requires harsh conditions and poses significant challenges. Herein, we demonstrate that replacing the terminal benzene ring of [6]helicene with a thiophene ring enables its photochemical transformation into coronene. Sulfur oxidation of the thiophene ring enables the corresponding thermal transformation, and the terminal tetrafluorination of the opposite benzene ring further accelerates this process, yielding 1,2-difluorocoronene, as confirmed by X-ray crystallography. The transformation begins with an intramolecular Diels-Alder reaction, whose activation energy is significantly lowered by these structural changes. Our findings underscore the utility of strategic modifications such as sulfur oxidation and fluorination in promoting this "helix-to-disc" conversion and opening new avenues for synthesizing functional polycyclic aromatics.

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.

Detailed analysis of Japanese patients with adenosine deaminase 2 deficiency reveals characteristic elevation of type II interferon signature and STAT1 hyperactivation.

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive inflammatory disease caused by loss-of-function mutations in both alleles of the ADA2 gene. Most patients with DADA2 exhibit systemic vasculopathy consistent with polyarteritis nodosa, but large phenotypic variability has been reported, and the pathogenesis of DADA2 remains unclear. OBJECTIVES: This study sought to assess the clinical and genetic characteristics of Japanese patients with DADA2 and to gain insight into the pathogenesis of DADA2 by multi-omics analysis. METHODS: Clinical and genetic data were collected from 8 Japanese patients with DADA2 diagnosed between 2016 and 2019. ADA2 variants in this cohort were functionally analyzed by in vitro overexpression analysis. PBMCs from 4 patients with DADA2 were subjected to transcriptome and proteome analyses. Patient samples were collected before and after introduction of anti- TNF-α therapies. Transcriptome data were compared with those of normal controls and patients with other autoinflammatory diseases. RESULTS: Five novel ADA2 variants were identified in these 8 patients and were confirmed pathogenic by in vitro analysis. Anti-TNF-α therapy controlled inflammation in all 8 patients. Transcriptome and proteome analyses showed that upregulation of type II interferon signaling was characteristic of DADA2. Network analysis identified STAT1 as a key regulator and a hub molecule in DADA2 pathogenesis, a finding supported by the hyperactivation of STAT1 in patients' monocytes and B cells after IFN-γ stimulation. CONCLUSIONS: Type II interferon signaling and STAT1 are associated with the pathogenesis of DADA2.

Hematopoietic Cell Transplantation with Reduced Intensity Conditioning Using Fludarabine/Busulfan or Fludarabine/Melphalan for Primary Immunodeficiency Diseases.

PURPOSE: The purpose of our study was to compare the safety and efficacy of hematopoietic cell transplantation (HCT) using fludarabine (Flu)-based reduced intensity conditioning (RIC) with busulfan (BU) or melphalan (Mel) for primary immunodeficiency diseases (PID). METHODS: We retrospectively analyzed transplant outcome, including engraftment, chimerism, immune reconstitution, and complications in 15 patients with severe combined immunodeficiency (SCID) and 27 patients with non-SCID PID. The patients underwent Flu-based RIC-HCT with BU (FluBU: 7 SCID, 16 non-SCID) or Mel (FluMel: 8 SCID, 11 non-SCID). The targeted low-dose BU with therapeutic drug monitoring was set to 30 mg hour/L for SCID. RESULTS: The 2-year overall survival of all patients was 79.6% and that of patients with SCID in the FluBU and FluMel groups was 100% and 62.5%, respectively. In the FluBU group, all seven patients achieved engraftment, good immune reconstitution, and long-term survival. All five patients receiving umbilical cord blood transplantation achieved complete or high-level mixed chimerism and sufficient specific IgG production. In the FluMel group, six of eight patients achieved complete or high-level mixed chimerism. Viral reactivation or new viral infection occurred in one FluBU group patient and four FluMel group patients. In the non-SCID group, 10 of 11 patients (91%) who received FluMel achieved complete or high-level mixed chimerism but had variable outcomes. Patients with WAS (2/2 patients), NEMO deficiency (2/2 patients), and X-linked hyper IgM syndrome (2/3 patients) who received FluBU achieved complete or high-level mixed chimerism and long-term survival. CONCLUSIONS: RIC-HCT with FluBU is a safe and effective strategy for obtaining high-level donor chimerism, immune reconstitution including B cell function, and long-term survival in patients with SCID. In patients with non-SCID PID, the results varied according to the subtype of the disease. Further prospective studies are required to optimize the conditioning regimen for non-SCID PID.

Autosomal recessive complete STAT1 deficiency caused by compound heterozygous intronic mutations.

Autosomal recessive (AR) complete signal transducer and activator of transcription 1 (STAT1) deficiency is an extremely rare primary immunodeficiency that causes life-threatening mycobacterial and viral infections. Only seven patients from five unrelated families with this disorder have been so far reported. All causal STAT1 mutations reported are exonic and homozygous. We studied a patient with susceptibility to mycobacteria and virus infections, resulting in identification of AR complete STAT1 deficiency due to compound heterozygous mutations, both located in introns: c.128+2 T>G and c.542-8 A>G. Both mutations were the first intronic STAT1 mutations to cause AR complete STAT1 deficiency. Targeted RNA-seq documented the impairment of STAT1 mRNA expression and contributed to the identification of the intronic mutations. The patient's cells showed a lack of STAT1 expression and phosphorylation, and severe impairment of the cellular response to IFN-γ and IFN-α. The case reflects the importance of accurate clinical diagnosis and precise evaluation, to include intronic mutations, in the comprehensive genomic study when the patient lacks molecular pathogenesis. In conclusion, AR complete STAT1 deficiency can be caused by compound heterozygous and intronic mutations. Targeted RNA-seq-based systemic gene expression assay may help to increase diagnostic yield in inconclusive cases after comprehensive genomic study.

APRIL-dependent lifelong plasmacyte maintenance and immunoglobulin production in humans.

BACKGROUND: Interactions between the tumor necrosis factor (TNF) ligand superfamily and TNF receptor superfamily play critical roles in B-cell development and maturation. A proliferation-inducing ligand (APRIL), a member of the TNF ligand superfamily, is secreted from myeloid cells and known to induce the differentiation of memory B cells to plasmacytes. OBJECTIVE: We sought to elucidate the role of APRIL in B-cell differentiation and immunoglobulin production through the analysis of complete APRIL deficiency in human. METHODS: We performed whole exome sequencing in a patient with adult common variable immunodeficiency. His parents were in a consanguineous marriage. TNFSF13 mRNA and protein expression were analyzed in the primary cells and plasma from the patient and in cDNA-transfected cells and supernatants of the cultures in vitro. Immunologic analysis was performed by using flow cytometry and next-generation sequencing. Monocyte-derived dendritic cells differentiated from induced pluripotent stem cells (iPSC-moDCs) were cocultured with memory B cells from healthy controls to examine in vitro plasmacyte differentiation. RESULTS: We identified a homozygous frameshift mutation in TNFSF13, the gene encoding APRIL, in the patient. APRIL mRNA and protein were completely absent in the monocytes and iPSC-moDCs of the patient. In contrast to the results of previous animal model studies, the patient showed hypogammaglobulinemia with a markedly reduced level of plasmacytes in peripheral blood and a clearly increased level of circulating marginal zone B cells. Although iPSC-moDC-induced in vitro plasmacyte differentiation was reduced in the patient, recombinant APRIL supplementation corrected this abnormality. CONCLUSION: The first APRIL deficiency in an adult patient with common variable immunodeficiency revealed the role of APRIL in lifelong maintenance of plasmacytes and immunoglobulin production in humans.

Whole-Exome Sequencing-Based Approach for Germline Mutations in Patients with Inborn Errors of Immunity.

PURPOSE: Owing to recent technological advancements, using next-generation sequencing (NGS) and the accumulation of clinical experiences worldwide, more than 420 genes associated with inborn errors of immunity (IEI) have been identified, which exhibit large genotypic and phenotypic variations. Consequently, NGS-based comprehensive genetic analysis, including whole-exome sequencing (WES), have become more valuable in the clinical setting and have contributed to earlier diagnosis, improved treatment, and prognosis. However, these approaches have the following disadvantages that need to be considered: a relatively low diagnostic rate, high cost, difficulties in the interpretation of each variant, and the risk of incidental findings. Thus, the objective of this study is to review our WES results of a large number of patients with IEI and to elucidate patient characteristics, which are related to the positive WES result. METHODS: We performed WES for 136 IEI patients with negative conventional screening results for candidate genes and classified these variants depending on validity of their pathogenicity. RESULTS: We identified disease-causing pathogenic mutations in 36 (26.5%) of the patients which were found in known IEI-causing genes. Although the overall diagnostic rate was not high and was not apparently correlated with the clinical subcategories and severity, we revealed that earlier onset with longer duration of diseases were associated with positive WES results, especially in pediatric cases. CONCLUSIONS: Most of the disease-causing germline mutations were located in the known IEI genes which could be predicted using patients' clinical characteristics. These results may be useful when considering appropriate genetic approaches in the clinical setting.

Hematopoietic stem cell transplantation for progressive combined immunodeficiency and lymphoproliferation in patients with activated phosphatidylinositol-3-OH kinase δ syndrome type 1.

BACKGROUND: Activated phosphatidylinositol-3-OH kinase δ syndrome type 1 (APDS1) is a recently described primary immunodeficiency syndrome characterized by recurrent respiratory tract infections, lymphoid hyperplasia, and Herpesviridae infections caused by germline gain-of-function mutations of PIK3CD. Hematopoietic stem cell transplantation (HSCT) can be considered to ameliorate progressive immunodeficiency and associated malignancy, but appropriate indications, methods, and outcomes of HSCT for APDS1 remain undefined. OBJECTIVE: Our objective was to analyze the clinical manifestations, laboratory findings, prognosis, and treatment of APDS1 and explore appropriate indications and methods of HSCT. METHODS: We reviewed retrospectively the medical records of cohorts undergoing HSCT at collaborating facilities. RESULTS: Thirty-year overall survival was 86.1%, but event-free survival was 39.6%. Life-threatening events, such as severe infections or lymphoproliferation, were frequent in childhood and adolescence and were common indications for HSCT. Nine patients underwent HSCT with fludarabine-based reduced-intensity conditioning. Seven patients survived after frequent adverse complications and engraftment failure. Most symptoms improved after HSCT. CONCLUSION: Patients with APDS1 showed variable clinical manifestations. Life-threatening progressive combined immunodeficiency and massive lymphoproliferation were common indications for HSCT. Fludarabine-based reduced-intensity conditioning-HSCT ameliorated clinical symptoms, but transplantation-related complications were frequent, including graft failure.

Hematopoietic stem cell transplantation in 29 patients hemizygous for hypomorphic IKBKG/NEMO mutations.

X-linked recessive ectodermal dysplasia with immunodeficiency is a rare primary immunodeficiency caused by hypomorphic mutations of the IKBKG gene encoding the nuclear factor κB essential modulator (NEMO) protein. This condition displays enormous allelic, immunological, and clinical heterogeneity, and therapeutic decisions are difficult because NEMO operates in both hematopoietic and nonhematopoietic cells. Hematopoietic stem cell transplantation (HSCT) is potentially life-saving, but the small number of case reports available suggests it has been reserved for only the most severe cases. Here, we report the health status before HSCT, transplantation outcome, and clinical follow-up for a series of 29 patients from unrelated kindreds from 11 countries. Between them, these patients carry 23 different hypomorphic IKBKG mutations. HSCT was performed from HLA-identical related donors (n = 7), HLA-matched unrelated donors (n = 12), HLA-mismatched unrelated donors (n = 8), and HLA-haploidentical related donors (n = 2). Engraftment was documented in 24 patients, and graft-versus-host disease in 13 patients. Up to 7 patients died 0.2 to 12 months after HSCT. The global survival rate after HSCT among NEMO-deficient children was 74% at a median follow-up after HSCT of 57 months (range, 4-108 months). Preexisting mycobacterial infection and colitis were associated with poor HSCT outcome. The underlying mutation does not appear to have any influence, as patients with the same mutation had different outcomes. Transplantation did not appear to cure colitis, possibly as a result of cell-intrinsic disorders of the epithelial barrier. Overall, HSCT can cure most clinical features of patients with a variety of IKBKG mutations.

Dysregulation of Epstein-Barr Virus Infection in Hypomorphic ZAP70 Mutation.

Background: Some patients with genetic defects develop Epstein-Barr virus (EBV)-associated lymphoproliferative disorder (LPD)/lymphoma as the main feature. Hypomophic mutations can cause different clinical and laboratory manifestations from null mutations in the same genes. Methods: We sought to describe the clinical and immunologic phenotype of a 21-month-old boy with EBV-associated LPD who was in good health until then. A genetic and immunologic analysis was performed. Results: Whole-exome sequencing identified a novel compound heterozygous mutation of ZAP70 c.703-1G>A and c.1674G>A. A small amount of the normal transcript was observed. Unlike ZAP70 deficiency, which has been previously described as severe combined immunodeficiency with nonfunctional CD4+ T cells and absent CD8+ T cells, the patient had slightly low numbers of CD8+ T cells and a small amount of functional T cells. EBV-specific CD8+ T cells and invariant natural killer T (iNKT) cells were absent. The T-cell receptor repertoire, determined using next generation sequencing, was significantly restricted. Conclusions: Our patient showed that a hypomorphic mutation of ZAP70 can lead to EBV-associated LPD and that EBV-specific CD8+ T cells and iNKT cells are critically involved in immune response against EBV infection.

Clinical and Immunological Characterization of ICF Syndrome in Japan.

OBJECTIVE: Immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a rare autosomal recessive primary immunodeficiency. Hypogammaglobulinemia is a major manifestation of ICF syndrome, but immunoglobulin replacement therapy does not seem to be effective for some ICF patients. Therefore, we aimed to reassess the immunological characteristics of this syndrome. METHODS: Eleven Japanese patients with ICF syndrome were enrolled. We performed whole-exome sequencing in four cases and homozygosity mapping using SNP analysis in two. We evaluated their clinical manifestations and immunological status. RESULTS: We newly diagnosed six ICF patients who had tentatively been diagnosed with common variable immunodeficiency. We identified two novel mutations in the DNMT3B gene and one novel mutation in the ZBTB24 gene. All patients showed low serum IgG and/or IgG2 levels and were treated by periodic immunoglobulin replacement therapy. Three of the six patients showed worse results of the mitogen-induced lymphocyte proliferation test. Analyses of lymphocyte subpopulations revealed that CD19+CD27+ memory B cells were low in seven of nine patients, CD3+ T cells were low in three patients, CD4/8 ratio was inverted in five patients, CD31+ recent thymic emigrant cells were low in two patients, and CD19+ B cells were low in four patients compared with those in the normal controls. ICF2 patients showed lower proportions of CD19+ B cells and CD16+56+ NK cells and significantly higher proportions of CD3+ T cells than ICF1 patients. T cell receptor excision circles were undetectable in two patients. Despite being treated by immunoglobulin replacement therapy, three patients died of influenza virus, fatal viral infection with persistent Epstein-Barr virus infection, or JC virus infection. One of three dead patients showed normal intelligence with mild facial anomaly. Two patients presented with autoimmune or inflammatory manifestations. Infectious episodes decreased in three patients who were started on trimethoprim-sulfamethoxazole and/or antifungal drugs in addition to immunoglobulin replacement therapy. These patients might have suffered from T cell immunodeficiency. CONCLUSION: These results indicate that patients with ICF syndrome have a phenotype of combined immunodeficiency. Thus, to achieve a better prognosis, these patients should be treated as having combined immunodeficiency in addition to receiving immunoglobulin replacement therapy.

Droplet Digital PCR-Based Chimerism Analysis for Primary Immunodeficiency Diseases.

OBJECTIVE: In the current study, we aimed to accurately evaluate donor/recipient or male/female chimerism in samples from patients who underwent hematopoietic stem cell transplantation (HSCT). METHODS: We designed the droplet digital polymerase chain reaction (ddPCR) for SRY and RPP30 to detect the male/female chimerism. We also developed mutation-specific ddPCR for four primary immunodeficiency diseases. RESULTS: The accuracy of the male/female chimerism analysis using ddPCR was confirmed by comparing the results with those of conventional methods (fluorescence in situ hybridization and short tandem repeat-PCR) and evaluating dilution assays. In particular, we found that this method was useful for analyzing small samples. Thus, this method could be used with patient samples, especially to sorted leukocyte subpopulations, during the early post-transplant period. Four mutation-specific ddPCR accurately detected post-transplant chimerism. CONCLUSION: ddPCR-based male/female chimerism analysis and mutation-specific ddPCR were useful for all HSCT, and these simple methods contribute to following the post-transplant chimerism, especially in disease-specific small leukocyte fractions.

Genetic heterogeneity of uncharacterized childhood autoimmune diseases with lymphoproliferation.

Autoimmune diseases in children are rare and can be difficult to diagnose.  Single causative genes have been identified for some pediatric autoimmune diseases. Such orphan diseases may not be diagnosed properly due to the variability of patients' phenotypes. Guidelines for the diagnostic process need to be developed. Fifteen patients with uncharacterized childhood autoimmune diseases with lymphoproliferation that had negative testing for autoimmune lymphoproliferative syndrome were subjected to whole-exome sequencing to identify genes associated with these conditions. Five causative genes, CTLA4, STAT3, TNFAIP3, IKZF1, and PSTPIP1, were identified. These genes should be considered as candidates for uncharacterized childhood autoimmune diseases with lymphoproliferation.

Haploinsufficiency of TNFAIP3 (A20) by germline mutation is involved in autoimmune lymphoproliferative syndrome.

BACKGROUND: Autoimmune diseases in children are rare and can be difficult to diagnose. Autoimmune lymphoproliferative syndrome (ALPS) is a well-characterized pediatric autoimmune disease caused by mutations in genes associated with the FAS-dependent apoptosis pathway. In addition, various genetic alterations are associated with the ALPS-like phenotype. OBJECTIVE: The aim of the present study was to elucidate the genetic cause of the ALPS-like phenotype. METHODS: Candidate genes associated with the ALPS-like phenotype were screened by using whole-exome sequencing. The functional effect of the identified mutations was examined by analyzing the activity of related signaling pathways. RESULTS: A de novo heterozygous frameshift mutation of TNF-α-induced protein 3 (TNFAIP3, A20), a negative regulator of the nuclear factor κB pathway, was identified in one of the patients exhibiting the ALPS-like phenotype. Increased activity of the nuclear factor κB pathway was associated with haploinsufficiency of TNFAIP3 (A20). CONCLUSION: Haploinsufficiency of TNFAIP3 (A20) by a germline heterozygous mutation leads to the ALPS phenotype.

Abnormal hematopoiesis and autoimmunity in human subjects with germline IKZF1 mutations.

BACKGROUND: Ikaros, which is encoded by IKZF1, is a transcriptional factor that play a critical role in hematopoiesis. Somatic IKZF1 alterations are known to be involved in the pathogenesis of leukemia in human subjects. Recently, immunodeficiency caused by germline IKZF1 mutation has been described. OBJECTIVE: We sought to describe the clinical and immunologic phenotypes of Japanese patients with heterozygous IKZF1 mutations. METHODS: We performed whole-exome sequencing in patients from a dysgammaglobulinemia or autoimmune disease cohort and used a candidate gene approach in 4 patients. Functional and laboratory studies, including detailed lymphopoiesis/hematopoiesis analysis in the bone marrow, were performed. RESULTS: Nine patients from 6 unrelated families were identified to have heterozygous germline mutations in IKZF1. Age of onset was 0 to 20 years (mean, 7.4 years). Eight of 9 patients presented with dysgammaglobulinemia accompanied by B-cell deficiency. Four of 9 patients had autoimmune disease, including immune thrombocytopenic purpura, IgA vasculitis, and systemic lupus erythematosus. Nonautoimmune pancytopenia was observed in 1 patient. All of the mutant Ikaros protein demonstrated impaired DNA binding to the target sequence and abnormal diffuse nuclear localization. Flow cytometric analysis of bone marrow revealed reduced levels of common lymphoid progenitors and normal development of pro-B to pre-B cells. CONCLUSIONS: Germline heterozygous IKZF1 mutations cause dysgammaglobulinemia; hematologic abnormalities, including B-cell defect; and autoimmune diseases.

Flow cytometry-based diagnosis of primary immunodeficiency diseases.

Primary immunodeficiencies (PIDs) are a heterogeneous group of inherited diseases of the immune system. The definite diagnosis of PID is ascertained by genetic analysis; however, this takes time and is costly. Flow cytometry provides a rapid and highly sensitive tool for diagnosis of PIDs. Flow cytometry can evaluate specific cell populations and subpopulations, cell surface, intracellular and intranuclear proteins, biologic effects associated with specific immune defects, and certain functional immune characteristics, each being useful for the diagnosis and evaluation of PIDs. Flow cytometry effectively identifies major forms of PIDs, including severe combined immunodeficiency, X-linked agammaglobulinemia, hyper IgM syndromes, Wiskott-Aldrich syndrome, X-linked lymphoproliferative syndrome, familial hemophagocytic lymphohistiocytosis, autoimmune lymphoproliferative syndrome, IPEX syndrome, CTLA 4 haploinsufficiency and LRBA deficiency, IRAK4 and MyD88 deficiencies, Mendelian susceptibility to mycobacterial disease, chronic mucocuneous candidiasis, and chronic granulomatous disease. While genetic analysis is the definitive approach to establish specific diagnoses of PIDs, flow cytometry provides a tool to effectively evaluate patients with PIDs at relatively low cost.

Maternal T and B cell engraftment in two cases of X-linked severe combined immunodeficiency with IgG1 gammopathy.

X-linked severe combined immunodeficiency (X-SCID), caused by defects in the common gamma chain, is typically characterized by T and NK cell defects with the presence of B cells. T cell dysfunction and impaired class-switch recombination of B cells mean that patients typically have defects in class-switched immunoglobulins (IgG, IgA, and IgE) with detectable IgM. Here, we describe two patients with X-SCID with IgG1 gammopathy, in whom we identified maternal T and B cell engraftment. Exclusively, maternal B cells were found among the IgD-CD27+ class-switched memory B cells, whereas the patients' B cells remained naïve. In vitro stimulation with CD40L+IL-21 revealed that peripheral blood cells from both patients produced only IgG1. Class-switched maternal B cells had restricted receptor repertoires with various constant regions and few somatic hypermutations. In conclusion, engrafted maternal B cells underwent class-switch recombination and produced immunoglobulin, causing hypergammaglobulinemia in patients with X-SCID.

Multicolor Flow Cytometry for the Diagnosis of Primary Immunodeficiency Diseases.

PURPOSE: Primary immunodeficiency diseases (PIDDs) are rare inherited diseases that impair the human immune system. We established a multicolor flow cytometric assay to comprehensively evaluate the immune status and immunological characteristics of patients with PIDDs. METHODS: Fifty-nine normal controls and 75 patients with PIDDs, including X-linked severe combined immunodeficiency (X-SCID), X-linked agammaglobulinemia (XLA), X-linked hyper IgM syndrome (X-HIGM), ataxia telangiectasia (AT), Wiskott-Aldrich syndrome (WAS), hyper IgE syndrome (HIES), and chronic mucocutaneous candidiasis disease (CMCD), were enrolled in this study. Immunophenotyes were evaluated by multicolor flow cytometry using seven different panels that allowed the detection of major leukocyte populations in peripheral blood. RESULTS: Multicolor flow cytometry revealed distinct leukocyte populations and immunological features of patients with X-SCID, XLA, X-HIGM, AT, WAS, HIES, and CMCD. CONCLUSIONS: Immunophenotyping by multicolor flow cytometry is useful to evaluate immune status and contributes to the diagnosis and management of patients with PIDDs.

Hematopoietic Stem Cell Transplantation for XIAP Deficiency in Japan.

BACKGROUND: X-linked inhibitor of apoptosis protein (XIAP) deficiency is a rare immunodeficiency that is characterized by recurrent hemophagocytic lymphohistiocytosis (HLH) and splenomegaly and sometimes associated with refractory inflammatory bowel disease (IBD). Although hematopoietic stem cell transplantation (HSCT) is the only curative therapy, the outcomes of HSCT for XIAP deficiency remain unsatisfactory compared with those for SLAM-associated protein deficiency and familial HLH. AIM: To investigate the outcomes and adverse events of HSCT for patients with XIAP deficiency, a national survey was conducted. METHODS: A spreadsheet questionnaire was sent to physicians who had provided HSCT treatment for patients with XIAP deficiency in Japan. RESULTS: Up to the end of September 2016, 10 patients with XIAP deficiency had undergone HSCT in Japan, 9 of whom (90%) had survived. All surviving patients had received a fludarabine-based reduced intensity conditioning (RIC) regimen. Although 5 patients developed post-HSCT HLH, 4 of them survived after etoposide administration. In addition, the IBD associated with XIAP deficiency improved remarkably after HSCT in all affected cases. CONCLUSION: The RIC regimen and HLH control might be important factors for successful HSCT outcomes, with improved IBD, in patients with XIAP deficiency.