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.

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.

This article is dedicated to one of the auto-respiratory syndromes – adenosine deaminase deficiency 2 (deficiency of adenosine deaminase 2 – DADA2) in the 12-year-old. This rare disease is caused by mutations in the ADA2 gene (CECR1), that encodes the ADA2 protein. Clinical manifestations of DADA2 are very diverse and usually include systemic inflammatory reaction in the form of fever attacts, vasculopathy in the form of livedo reticulum, polyarteritis nodosa, ischemic and/or hemorrhagic strokes, as well as signs of immunodeficiency with hypogammaglobulinemia and bone marrow failure. Complex pathogenetic mechanisms, variety of clinical manifestations complicate both diagnosis of the disease and trial of pathogenetic therapy in patients with DADA2. The article describes DADA2 patient care, as well as provides present state analysis of the DADA2 problem in the world, including terminology, historical references, pathogenesis, diagnosis problems and clinical manifestations.

Chronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory disease from the group of multifactorial diseases. It is characterized by non-infectious recurrent bone lesions, usually manifesting in childhood. The aim of this study was to analyze the clinical, laboratory, radiological and histological data of 33 patients (12 boys, 21 girls) with a diagnosis of chronic nonbacterial osteomyelitis. 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. 25/33 patients were hospitalized to the Center with suspected neoplastic disease bone. The median age of CNO manifestation was 9.6 years. 24/33 had a multi-focal form of the disease. 5 patients had fever. Nonsteroidal anti-inflammatory drugs were the first therapy for all patients, achieving clinical remission in 4 cases. Zoledronic acid were used in 29 patients with remission in 19, adalimumab in 10 patient with remission in 9. In one patient stabilization was achieved only with the combination  of methotrexate and canakinumab therapy.

The aim of this study was to analyze the clinical, laboratory and molecular genetic data of 26 patients (15 boys, 11 girls) diagnosed with mevalonate kinase deficiency syndrome (MKD).Subjects and methods. The age of MKD manifestation ranged from 0 to 30.0 months (M – 1.5 months). Clinical manifestations and their severity were extremely diverse: from symptoms resembling Marshall’s syndrome to severe systemic manifestations with respiratory failure, hepatosplenomegaly and pancytopenia.Results/Conclusion. All patients had homozygous/compound-heterozygous mutations in the MVK gene, including 10 newly described variants. In all 20 patients, who have been treated with IL-1 inhibitors long enough to assess the effect of the treatment, drastic improvement of the condition was noted, but only in 17/20 patients achieved full remission.

Primary immunodeficiencies (PID) are caused by defects in genes of immune system. The mutations may occur de novo or can be inherited. The frequency of familial PID cases varies in different populations and depends on multiple factors. The aim of this study was to analyze familial PID cases among pediatric patients from NMRCPHOI D. Rogachev. The study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI. 1075 children from 1020 families with molecular PID diagnosis were analyzed retrospectively. One hundred and forty-six children had at least one relative with the same disorder; mutations were identified in 31 PID’s genes. The frequency of familial cases was 13.6%. The proportion of families with two or more affected children was 5.4%. Patients born in a consanguineous marriage made up 3% of the observed children. Autosomal dominant PID were typical for families with affected adult relatives. Because of the high amount of familial cases, all parents of children with PID as well as adult PID patients of childbearing age should seek a familial genetic counselling immediately after the corresponding diagnosis. Patients whose PID diagnosis has not been genetically verified, should be urgently tested to find an underlying molecular genetic cause of the disease. Prenatal/preimplantation diagnostic and screening of their close relatives are very important in these families.

The article presents data on the features of COVID-19 infection in patients with primary immunodeficiencies (PIDs) in the Russian Federation, obtained through the National association of experts in PID (NAEPID) registry. Materials and methods: from March 1, 2020 to October 15, 2020, 15 cases of close intrafamilial contact between PIDs patients and COVID-19 patients without reliable infection of the first and 23 cases of COVID-19 infection in PIDs patients were reported. Results: 6/23 infected people had asymptomatic course of infection, 9/23 patients – mild form, 8/23 – moderate form of disease, one patient had a severe course with a fatal outcome. 19/23 patients were under 18 years of age, which corresponds with the age data of the national Russia PID registry. Conclusion: perhaps this age composition partially explains the milder course of COVID-19 in PIDs patients compared to the European data. Other possible reasons for a milder course may be the lower pathogenicity of the coronavirus strain circulating in the Russian Federation.

Epstein–Barr virus-associated smooth muscle tumors (EBV-SMTs) are rare soft tissue neoplasms that typically occur in conditions of secondary immunodeficiency due to human immunodeficiency virus or immunosuppression after organ transplantation. Beyond that, EBV-SMTs occur in patients with primary immunodeficiencies (PIDs). EBV-SMTs pathogenesis is still unclear but it was shown that the key mechanism of the tumor development is T- and NK-cell defect. Treatment strategy depends not only on tumor localization and resectability, but also on immunodeficiency etiology and its correction possibility. Here we report literature review and two patients with combined PIDs (CARMIL2- and ATM-genes deficiency) who developed EBV-SMT. In each case, the parents gave consent to the use of their child's data, including photographs, for research purposes and in publications.

This article describes clinical case of a child with proteasome-associated autoinflammatory syndrome-2 (PRAAS2). First two cases in unrelated boys were described in July, 2018 by M. Cecilia Poli, Frederic Ebstein. We describe another case of PRAAS2. Mutations of the POMP-gene underlie PRAAS2 pathogenesis, causing defects of the POMP protein which plays important role in proteasomes maturation and leads to the clinical symptoms observed in three described cases. We also provide a short PRAAS2 background description, as well as key pathogenesis components, clinical findings description and analysis of three known PRAAS2 cases. Parents gave their consent to use personal data, including photos for clinical research and publications.

IgG4-related disease is an extremely rare disorder, сcharacterized by the inflammatory infiltration of various organs, with predominance of IgG4-positive plasma cells, fibrosis and high IgG4 plasma concentration. Treatment regiments have not been optimized, especially in children. Here we discuss a case of IgG4-related disease of the orbit in a 13 year old boy and our new treatment approach involving JAK-kinase inhibitor ruxolitininb. The article also presents analysis of the state of the problem of IgG4-related disease it he world, including terminology, historical references, pathogenesis, diagnostic problems and clinical manifestations.

Hyper-IgD syndrome, one of the forms of mevalonate kinase deficiency (MKD), is a rare autosomal recessive disorder caused by mutation in the MVK gene. The disease usually starts in early age. The most specific clinical manifestation includes recurrent episodes of fever, abdominal pain, diarrhea, vomiting, arthralgia, and lymphadenopathy. However, not all patients present with the typical clinical features of MKD. A retrospective analysis of clinical manifestations and results of therapy of 6 children (4 girls, 2 boys) with MKD is carried out. The first symptoms of the disease manifested during the first 6 months of life in all the patients. All patients suffered from periodical fever, lymphadenopathy (mainly the cervical nodes were involved), abdominal pain, nausea/vomiting. Five patients had diarrhea, sometimes with blood, and one patient suffered from chronic constipation. Rash was observed in 4 patients, myalgia and arthralgia in 4, aphthous stomatitis in 5, and neurological symptoms in 2 patients. One patient developed periorbital edema and eyelid hyperemia during an attack: these symptoms were not described previously. One patient died under conditions of macrophage activation syndrome and amyloidosis. Four of six patients received interleukin-1 inhibitors (anakinra and/or canakinumab), which led to clinical and laboratory remission.

Cryopyrin-Associated Periodic Syndrome (CAPS) refers to a group of autoinflammatory diseases and is caused by autosomal dominant mutations of the NLRP3 gene coding. Relapsing fever, rash, laboratory changes and inflammatory lesions of various organs are typical manifestations of CAPS. Inhibitors of interleukin 1, including canakinumab, are modern means of pathogenetic therapy of patients with CAPS. The article presents the treatment results in 5 pediatric patients with CAPS. Application of canakinumab led to the relief of all major symptoms (fever, inflammatory changes in the blood lymphoproliferation, signs of organ damage), and no relevant side effects was detected.