Subcutaneous immunoglobulin (SCIG) preparations are widely used in patients with inborn errors of immunity (IEI), with proven efficacy and good tolerance. We assessed treatment efficacy, safety, and quality of life in a large cohort of IEI patients who switched from intravenous immunoglobulin (IVIG) to SCIG. Our observational study included 200 patients aged 1–65 years with IEI. SCIG Cutaquig (16.5%) was administered every 7–10 days for at least 12 months via the rapid push method. We assessed the rate of infection, immunoglobulin G (IgG) concentration, adverse events, and quality of life. A total of 8,787 SCIG doses were administered during the study. The rate of infections (per person/month) during SCIG treatment was 0.05, which was significantly lower compared to 0.19 during the IVIG period (p<0.001). The median trough IgG was 6.9 g/L on IVIG, compared to 9.0 g/L during the first six months, and 9.2 g/L during the next six months on SCIG. Systemic reactions occurred in 12.4% of the IVIG infusions and 1.9% of the SCIG infusions. The total scores on quality of life summary assessments of physical and mental health were higher on SCIG therapy compared with IVIG (p<0.001). At the end of the study, 85.6% of the patients chose to remain on SCIG. Our data suggest that SCIG infusion via the rapid push method is effective, well tolerated, and feasible in large groups of IEI patients, including those in large countries such as Russia.

We have identified a new inherited bone marrow (BM) failure syndrome with severe congenital neutropenia (CN) caused by autosomal recessive mutations in the coatomer protein complex I (COPI) subunit zeta 1 (COPZ1) gene. A stop-codon COPZ1 mutation and a missense mutation were found in three patients from two unrelated families. While two affected siblings with a stop-codon COPZ1 mutation suffered from congenital neutropenia (CN) that involves other hematological lineages, and non-hematological tissues, the patient with a missense COPZ1 mutation had isolated neutropenia. Both COPZ1 mutations were localized to a highly evolutionarily conserved region. The resulting truncated COPZ1 protein was predicted to display diminished interaction with its COPI complex partner, COPG1. These findings were consistent with the observed block in retrograde protein transport from the Golgi to the ER in human fibroblasts carrying truncated COPZ1. Human CD34+ cells with truncated or missense COPZ1 had significantly impaired granulocytic differentiation and in zebrafish embryos, truncated Copz1 also resulted in defective myelopoiesis. Intracellularly, truncated COPZ1 downregulated JAK/STAT/CEBPE/G-CSFR signaling and hypoxia-responsive pathways while inducing STING, interferon-stimulated genes, stimulating oxidative phosphorylation activity, and increasing reactive oxygen species (ROS) levels in CD34+ cells. Missense COPZ1 deregulated interferon and JAK/STAT signaling but less than the truncated protein. Finally, treatment with the small molecule HIF1α activator IOX2 or transduction of cells with COPZ2 cDNA restored defective granulopoiesis in COPZ1-mutated CD34+ cells, offering potential therapeutic options.

BackgroundThromboinflammation is caused by mutual activation of platelets and neutrophils. The site of thromboinflammation is determined by chemoattracting agents release by endothelium, immune cells, and platelets. Impaired neutrophil chemotaxis contributes to the pathogenesis of Shwachman-Diamond syndrome (SDS). In this hereditary disorder, neutrophils are known to have aberrant chemoattractant-induced F-actin properties. Here, we aim to determine whether neutrophil chemotaxis could be analyzed using our previously developed ex vivo assay of the neutrophils crawling among the growing thrombi.MethodsAdult and pediatric healthy donors, alongside with pediatric patients with SDS, were recruited for the study. Thrombus formation and granulocyte movement in hirudinated whole blood were visualized by fluorescent microscopy in fibrillar collagen-coated parallel-plate flow chambers. Alternatively, fibrinogen, fibronectin, vWF, or single tumor cells immobilized on coverslips were used. A computational model of chemokine distribution in flow chamber with a virtual neutrophil moving in it was used to analyze the observed data.ResultsThe movement of healthy donor neutrophils predominantly occurred in the direction and vicinity of thrombi grown on collagen or around tumor cells. For SDS patients or on coatings other than collagen, the movement was characterized by randomness and significantly reduced velocities. Increase in wall shear rates to 300-500 1/s led to an increase in the proportion of rolling neutrophils. A stochastic algorithm simulating leucocyte chemotaxis movement in the calculated chemoattractant field could reproduce the experimental trajectories of moving neutrophils for 72% of cells.ConclusionsIn samples from healthy donors, but not SDS patients, neutrophils move in the direction of large, chemoattractant-releasing platelet thrombi growing on collagen.

Primary immunodeficiencies (PIDs) or inborn errors of immunity (IEIs) are a heterogeneous group of genetically-determined diseases that are divided into ten groups according to modern classification. The high heterogeneity in clinical manifestations and pathogenetic mechanisms as well as wide use of immunoglobulin replacement therapy, various immunosuppressant and anti-inflammatory drugs make it difficult to decide on the safety and efficacy of vaccination for patients with IEIs. There are no universally accepted recommendations for vaccine prophylaxis among patients with IEIs both in Russia and Worldwide due to the lack of controlled clinical trials available. Authors have attempted summarizing the bibliographical sources available on the safety and efficacy of vaccine prophylaxis in individuals with different forms of IEIs considering the Authors’ own opinion raising the importance of controlled clinical trials.

We have identified new autosomal recessive mutations in the COPZ1 gene in three severe congenital neutropenia (CN) patients from two unrelated families. In one family, two siblings with a stop-codon COPZ1 mutation (NP_057141:p.Gln141Ter) suffered from CN, lymphopenia, anemia, thrombocytopenia, and syndromic organ involvement, including hepatosplenomegaly, atypical autism with mental retardation, varying degrees of bone defects, and dermatitis. An unrelated patient with a missense COPZ1 mutation (NP_057141:p.Gly132Arg) exhibited isolated CN and chilblains. The COPZ1 gene encodes the zeta 1 subunit of the coatomer protein complex I (COPI), which is phylogenetically highly conserved, with two identified mutation positions in the conserved region. The protein structure of human COPZ1 is still unknown, and computational analysis using bovine COPZ1 and COPG1 proteins predicted that truncated COPZ1 exhibits substantial structural instability and reduced interaction with COPG1, whereas missense COPZ1 retains interaction with COPG1. Consistent with structural defects, truncated COPZ1 blocked retrograde protein transport from the Golgi to the ER in human fibroblasts, suggesting a detrimental effect on COPI complex functions. We also found that truncated or missense COPZ1 mutations caused impaired granulocytic differentiation of human CD34+ cells in vitro with a more pronounced phenotype in COPZ1 truncated cells. In zebrafish embryos, truncated Copz1 also resulted in defective myelopoiesis. Intracellularly, truncated COPZ1 downregulated JAK-STAT-C/EBPE-G-CSFR signaling and hypoxia-responsive pathways while inducing interferon-stimulated genes (ISGs) and STING, stimulating oxidative phosphorylation activity, and increasing reactive oxygen species (ROS) levels in CD34+ cells. Missense COPZ1 protein also deregulated interferon signaling. Therapeutically, by applying connectivity map analysis, we discovered that treatment with the HIF1α activator IOX2 successfully restored granulopoiesis in truncated Copz1 zebrafish embryos and human CD34+ cells. Furthermore, transduction with COPZ2 cDNA effectively corrected granulocytic differentiation defects in COPZ1-mutated CD34+ cells. In summary, our findings elucidate the distinct pathogenic mechanisms and clinical presentations associated with truncated versus missense COPZ1 mutations and underscore the potential of HIF1α activation as a promising therapeutic approach for CN.

Schwachman-Diamond syndrome (SDS) is a rare autosomal recessive disease from the group of ribosomopathies characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, malnutrition, protein-energy malnutrition, growth retardation, skeletal abnormalities and a predisposition to the development of myelodysplastic syndrome and acute myeloid leukemia. Severe hematological disorders, a high risk of developing MDS/AML, with a high percentage of unfavorable outcomes, prompted the consideration of alternative routes for the therapy in these circumstances. The possibility for the use of L-leucine, an essential amino acid, as a pathogenetic therapy in patients with severe dyshematopoiesis in SDS by analogy with its use in another ribosomopathy disease, Diamond-Blackfan anemia (DBA), is discussed in the Article.

Mutations in the small Rho-family guanosine triphosphate hydrolase RAC2, critical for actin cytoskeleton remodeling and intracellular signal transduction, are associated with neonatal severe combined immunodeficiency (SCID), infantile neutrophilic disorder resembling leukocyte adhesion deficiency (LAD), and later-onset combined immune deficiency (CID). We investigated 54 patients (23 previously reported) from 37 families yielding 15 novel RAC2 missense mutations, including one present only in homozygosity. Data were collected from referring physicians and literature reports with updated clinical information. Patients were grouped by presentation: neonatal SCID (n = 5), infantile LAD-like disease (n = 5), or CID (n = 44). Disease correlated to RAC2 activity: constitutively active RAS-like mutations caused neonatal SCID, dominant-negative mutations caused LAD-like disease, whereas dominant-activating mutations caused CID. Significant T- and B-lymphopenia with low immunoglobulins were seen in most patients; myeloid abnormalities included neutropenia, altered oxidative burst, impaired neutrophil migration, and visible neutrophil macropinosomes. Among 42 patients with CID with clinical data, upper and lower respiratory infections and viral infections were common. Twenty-three distinct RAC2 mutations, including 15 novel variants, were identified. Using heterologous expression systems, we assessed downstream effector functions including superoxide production, p21-activated kinase 1 binding, AKT activation, and protein stability. Confocal microscopy showed altered actin assembly evidenced by membrane ruffling and macropinosomes. Altered protein localization and aggregation were observed. All tested RAC2 mutant proteins exhibited aberrant function; no single assay was sufficient to determine functional consequence. Most mutants produced elevated superoxide; mutations unable to support superoxide formation were associated with bacterial infections. RAC2 mutations cause a spectrum of immune dysfunction, ranging from early onset SCID to later-onset combined immunodeficiencies depending on RAC2 activity. This trial was registered at www.clinicaltrials.gov as #NCT00001355 and #NCT00001467.

Spleen is one of the most important peripheral organs of the immune system because it plays a decisive role in the regulation of immune homeostasis due to its ability to bind innate and adaptive immunity. Reduced spleen function (hyposplenia) and asplenia are risk factors for the development of fulminant sepsis caused by encapsulated bacteria such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b. Systematic and long-term treatment approaches after splenectomy can significantly reduce the risk of infection with encapsulated organisms among patients with asplenia and hyposplenism. This bibliographical review represents a few out of the most common forms of asplenia and hyposplenia in the immunologists’, hematologists’ practice and highlights the issue of vaccination and prophylactic antibiotic therapy in this group of patients as well since this aspect is a long-term perspective for preventing of fatal complications.

Shwachman–Diamond syndrome is a rare genetic disorder with an autosomal recessive inheritance pattern. Most often (in more than 90% of cases) this disease is caused by biallelic pathogenic variants in the highly conserved SBDS gene located on the long arm of chromosome 7. However, approximately 10% of patients with the clinical phenotype of Shwachman–Diamond syndrome lack mutations in SBDS but have pathogenic variants in other genes, such as DNAJC21 or EFL1. Shwachman–Diamond syndrome is a multisystemic disorder characterized by exocrine pancreatic insufficiency, protein-energy undernutrition, delayed physical development, cognitive disorders, anomalies of the skeletal system, and immunological disorders. In addition to the described symptoms, Shwachman–Diamond syndrome is characterized by the presence of bone marrow failure (most often neutropenia and anemia), as well as an increased risk of cytogenetic abnormalities and a predisposition to myelodysplastic syndromes and acute myeloid leukemia. In this review, the authors summarize the spectrum of hematological disorders observed in Shwachman–Diamond syndrome, as well as describe the molecular mechanisms underlying them.

Background: We developed a WES-based pipeline for finding new severe congenital neutropenia (CN) causative gene variants for patients without known underlying genetic defects. We have identified a novel homozygous stop-codon mutation p.Gln141Ter in the COPZ1 gene in two siblings with CN, signs of primary immunodeficiency and mental retardation. COPZ1 encodes a subunit of the coatomer protein complex I (COPI), which is involved in intracellular protein trafficking and autophagy. While COPZ1 is ubiquitously expressed, its paralogue, COPZ2, is not detected in blood and brain tissues. Aims: To investigate the role of COPZ1 mutation in defective granulopoiesis in vitro and in vivo. Methods: We introduced COPZ1 mutation in cord blood (CB) hematopoietic stem and progenitor cells (HSPCs) of healthy donors, induced pluripotent stem cells (iPSCs), AML cell line NB4 and zebrafish embryos using CRISPR/Cas9 gene-editing. We performed in-silico simulations of the mutant COPZ1 protein using the atomistic molecular dynamics program CHARMM. In addition, we conducted in vitro liquid culture differentiation (LCD) and colony-forming units (CFU) assays of COPZ1 mutant CB-HSPCs and embryoid body-based granulocytic differentiation and Western Blot of COPZ1 mutant iPSCs. Furthermore, we treated COPZ1 mutant NB4 with Tunicamycin to induce unfolded protein response (UPR) stress. Finally, we performed RNA-sequencing of COPZ1-mutated and control-edited HSPCs. Results: WB showed that COPZ1 mutation p.Gln141Ter results in the expression of truncated COPZ1 protein. CHARMM predicted that truncated COPZ1 alone and within the COPI complex displays significant structural instability compared to the full-length COPZ1, arguing for a disturbed COPI complex formation in the presence of truncated COPZ1. Compared to control edited cells, COPZ1-mutant CB-HSPCs have abrogated granulopoiesis in LCD and CFU assay. In vitro granulocytic differentiation of COPZ1-mutant iPSCs was also severely affected. In addition, copz1 mutant zebrafish embryos had a markedly lower number of neutrophils than the wild-type group. Furthermore, we confirmed that transduction of COPZ1 mutated HSPCs with WT COPZ2 rescued defective granulopoiesis triggered by truncated COPZ1. Thus, the organ-specific expression of COPZ2 may explain the neuro-hematological symptomatology and provide therapeutic opportunities. Analyses of RNA-seq data from mutant vs WT cells revealed a significant up-regulation of the NFKB and STING pathways and down-regulation of the JAK/STAT signalling pathway in mutant cells. STING expression is associated with inflammation and endoplasmic reticulum (ER) stress. Compared to the control group, COPZ1-mutant NB4 cells showed higher sensitivity to the tunicamycin-induced UPR as ER stress. Thus, we propose that COPZ1-mutant cells accumulate STING in the Golgi due to ineffective ER retrieval, triggering inflammation via the NFKB pathway and UPR/ER stress. Intriguingly, COPZ1-mutant HSPCs showed downregulation of CLU, SRC, BNIP3/BNIP3L, and upregulation of TIGAR and NPC1 genes, all signs of suppressed autophagy. Summary/Conclusion: This is the first report on an immunodeficiency syndrome with CN caused by a homozygous stop-codon mutation in the COPZ1 gene. As a potential pathomechanism for neutropenia downstream of COPZ1-mutation, we suggest a pathological positive feedback between the STING inflammatory pathway and insufficient autophagy associated with UPR/ER stress. Finally, the rescue of COPZ1 mutated HSPCs with COPZ2 overexpression corrected the defective granulopoiesis, suggesting promising therapeutic avenues. Keywords: Severe congenital neutropenia, Bone marrow failure, Animal model, Zebra fish

Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome (WS) is a combined immunodeficiency caused by gain-of-function mutations in the C-X-C chemokine receptor type 4 ( CXCR4 ) gene. We characterize a unique international cohort of 66 patients, including 57 (86%) cases previously unreported, with variable clinical phenotypes. Of 17 distinct CXCR4 genetic variants within our cohort, 11 were novel pathogenic variants affecting 15 individuals (23%). All variants affect the same CXCR4 region and impair CXCR4 internalization resulting in hyperactive signaling. The median age of diagnosis in our cohort (5.5 years) indicates WHIM syndrome can commonly present in childhood, although some patients are not diagnosed until adulthood. The prevalence and mean age of recognition and/or onset of clinical manifestations within our cohort were infections 88%/1.6 years, neutropenia 98%/3.8 years, lymphopenia 88%/5.0 years, and warts 40%/12.1 years. However, we report greater prevalence and variety of autoimmune complications of WHIM syndrome (21.2%) than reported previously. Patients with versus without family history of WHIM syndrome were diagnosed earlier (22%, average age 1.3 years versus 78%, average age 5 years, respectively). Patients with a family history of WHIM syndrome also received earlier treatment, experienced less hospitalization, and had less end-organ damage. This observation reinforces previous reports that early treatment for WHIM syndrome improves outcomes. Only one patient died; death was attributed to complications of hematopoietic stem cell transplantation. The variable expressivity of WHIM syndrome in pediatric patients delays their diagnosis and therapy. Early-onset bacterial infections with severe neutropenia and/or lymphopenia should prompt genetic testing for WHIM syndrome, even in the absence of warts.

RASopathies are disorders caused by germline mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. These syndromes share features of developmental delay, facial dysmorphisms, and defects in various organs, as well as cancer predisposition. Somatic mutations of the same pathway are one of the primary causes of cancer. It is thought that germline cancer-causing mutations would be embryonic lethal, as a more severe phenotype was shown in Drosophila and zebrafish embryos with cancer MAP2K1 mutations than in those with RASopathy mutations. Here we report the case of a patient with RASopathy caused by a cancer-associated MAP2K1 p.Phe53Leu mutation. The postzygotic mosaic nature of this mutation could explain the patient's survival.

The aim of this study was to analyze the clinical and laboratory data of 101 patients (61 boys, 40 girls) diagnosed with PFAPA syndrome. The age of onset of PFAPA syndrome ranged from 8 to 36 months (the median age of onset was 18 months). The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation. In most cases, clinical manifestations included recurrent fevers, acute tonsillitis (in 84% of cases, the tonsils were covered with a whitish coating), and cervical lymphadenitis. More rarely, the patients had diarrhea, vomiting, myalgia, arthralgia, and rash. All of the patients met the criteria proposed by G.S. Marshall. Our management strategies for patients with PFAPA syndrome include symptomatic treatment with antipyretics, short-term glucocorticosteroid therapy, and tonsillectomy. The majority of patients have complete resolution of PFAPA symptoms by the age of 7 regardless of the type of therapy.

This paper presents a case of rare primary immunodeficiency belonging to the group of monogenic autoinflammatory diseases with PLCy2-associated antibody deficiency and immune dysregulation (APLAID). Here we describe our experience in the management of a 7-year-old child with this syndrome and discuss key information about the pathogenesis and clinical manifestations of APLAID based on the analysis of the known cases. Due to the rarity and novelty of the disease, there is a lack of established criteria for the identification and diagnosis of APLAID and no established standard of care. We report our experience of treating APLAID with a tumor necrosis factor-a inhibitor and our analysis of the effectiveness of treatment and adverse events. The patient's parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.

The aim of this study was to analyze the clinical, laboratory and molecular genetic data of 20 patients (9 boys, 11 girls) diagnosed with cryopyrin-associated periodic syndrome (CAPS) with an assessment of the efficacy and safety of therapy in 6 patients with an inhibitor of the interleukin-1 receptor – anakinra. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI. The patients' parents gave their consent to the use of their child's data, including photographs, for research purposes and in publications. The age of CAPS manifestation ranged from 0 to 27.0 months (median – 2 months). The clinical manifestations were dominated by fever, rash, lesions of the central nervous system, musculoskeletal system. During the attack, all 20 patients had an increase acute phase proteins of blood. All patients had heterozygous mutation in the NLRP3 gene, with the highest frequency of localization in exon 3 (17/20). 6/20 patients were initiated on anakinra therapy. All 6 patients who have been treated of anakinra enough to assess the effect of the treatment, drastic improvement of the condition was noted, but only in 5/6 patients achieved full remission.

GATA2 deficiency is one of the most common predisposing conditions for MDS in young individuals. It is characterized by autosomal dominant inheritance and a high rate of de novo mutations. Here we describe the clinical phenotype and hematological presentation of 10 pediatric patients with GATA2 deficiency presented to the Dmitry Rogachev Center between 2013 and 2020. All patients had been referred for neutropenia or suspected aplastic anemia. While some patients presented with an immunological phenotype, others displayed monosomy 7 and MDS. The clinical presentation with MDS in infancy and the constitutional phenotypes in our patients underline the great variability in clinical manifestation. Careful description of cohorts with GATA2 deficiency from different countries and genetic backgrounds will help to unravel the enormous heterogeneity of this recently discovered genetic disorder.

The article is devoted to an extremely rare variant of type I interferonopathies associated with a homozygous gain of function (GOF) mutation in the STAT2 gene in a 5-year-old child. This genetic defect was first described in 2019, and so far only 3 cases are known in the world with a similar pathology. Here we present the fourth clinical case and our experience in managing a patient with STAT2 GOF. The article presents the key aspects of the pathogenesis, clinical picture based on the analysis of all known cases of the disease. The absence of established criteria and methods of treatment for this disease is due to the rarity and relative novelty of the described nosology. We present the experience of treatment using a JAK kinase inhibitor, followed by an assessment of the effectiveness of the therapy and side effects. The patient's parents agreed to use the information, including the child's photo, in scientific research and publications.

Currently, the number of cases of malignant diseases in children is increasing, but the number of children who have recovered is also increasing. In the past few years, the number of deaths has decreased thanks to the latest technologies for treating cancer patients, but there are still a number of problems in the lives of small patients after treatment. One of the important problems is the lack of continuation of the mandatory vaccination of children who have undergone a malignant disease, according to age and in accordance with the national calendar, despite the availability of clinical guidelines in domestic and foreign publications on preventive vaccination of this cohort. Many physicians make unjustified medical exclusions from vaccination based only on their own biases, which can be justified by the limited number of publications on this topic. In turn, vaccination can reduce the number of deaths from infectious complications and provide hope for further full life. Children with malignant diseases should be vaccinated against infectious diseases that can be prevented with vaccines after completion and sometimes during treatment. For such patients, there should be a vaccination schedule that takes into account the available therapy that may lead to the suppression of immunity. This article is devoted to the vaccination of children with malignant diseases.

WHIM syndrome (warts, hypogammaglobulinemia, infections, myelokathexis) is a rare combined primary immunodeficiency. Here we describe 10 Russian patients with WHIM syndrome that were followed in the Dmitry Rogachev National Medical Research Center оf Pediatric Hematology, Oncology and Immunology. This study is supported by the Independent Ethics Committee and approved by the Academic Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. Neutropenia and lymphopenia were observed in all 10 patients, hypogammaglobulinemia – in 7/10 patients. In all cases bone marrow analysis demonstrated myelokathexis features (cytoplasmic vacuolization in neutrophils and eosinophils, hyperlobulated pyknotic nuclear lobes connected by long thin strands, hypogranular and hypersegmented neutrophils). All patients were treated with granulocyte colony-stimulating factor and intravenous immunoglobulin. In 3/10 poor disease control was an indication to perform HSCT. In 2 of 3 patients HSTC was successful and all symptoms of the disease resolved. In conclusion, the diagnosis of WHIM syndrome must be considered in patients with early onset of neutro- and lymphopenia in conjunction with morphological features of myelokathexis. Treatment of this disease is still a challenging problem.