Hemophagocytic lymphohistiocytosis (HLH) is polygenetic disease caused by mutations in genes associated with granule-dependent lymphocyte-mediated cytotoxicity (PRF1, UNC13D, STX11, STXBP2, LYST, AP3B1, AP3D1 RAB27A, XIAP, SH2D1A).

Our cohort of patients demonstrated a repeated mutation in the UNC13D genec.2346_2349delCTCC(p.R782fs), which may be associated with the “founder effect” in Slavic countries. Atypical manifestation causes difficulties in rapid diagnosis, fast sequencing of all PID genes are necessary for establishing correct diagnosis and start appropriate treatment.

The presence of coagulopathy as part of the systemic inflammatory response syndrome is a characteristic feature of severe coronavirus disease 2019 (COVID-19). Hematological changes (increased DD-dimer, prolonged activated partial thromboplastin clotting time [APTT] and prothrombin time [PT], high fibrinogen levels) have been observed in hospitalized patients with COVID-19, which characterize the risk of thrombotic events. Against the background of COVID-19 there is endothelial dysfunction, hypoxia and pulmonary congestion, mediated by thrombosis and microvascular occlusion. Up to 71.4% of patients who died from COVID-19 had disseminated intravascular coagulation syndrome, compared with only 0.6% of survivors. The main manifestation of COVID-19-associated coagulopathy is a significant increase in DD without a decrease in platelet count or prolongation of APTT and PT, indicating increased thrombin formation and the development of local fibrinolysis. An increase in DD levels of more than 3-4 times was associated with higher in-hospital mortality. Therefore, COVID-19 requires assessment of the severity of the disease for further tactics of thromboprophylaxis. The need for 1 continued thromboprophylaxis, or therapeutic anticoagulation, in patients after inpatient treatment for two weeks using imaging techniques to assess of thrombosis assessment.

As more data is collected, hematologists will be able to gain more insight into the impact of coronavirus disease 2019 (COVID-19) on pediatric patients with hematological malignancies. Material and methods: We analysed 21 cases of COVID-19 in pediatric patients with onco-hematological diseases treated in the Western Ukrainian Pediatric Medical Center from March 2020 through May 2021. The majority of patients (71.4%) were diagnosed with acute lymphoblastic leukemia. All patients from the analyzed cohort had an asymptomatic, mild or moderate course of coronavirus-19 infection. The most common symptoms of COVID-19 were fever, cough, gastrointestinal symptoms, and dermatitis. Severe severe acute respiratory syndrome coronavirus 2 increased the risk of liver toxicity and venous thrombosis. Results and conclusion: Our analysis showed that pediatric patients with hematological malignancies need the same treatment approach for COVID-19 as for other infective complications.

On Feb 24, 2022, Russian military forces began a coordinated invasion of Ukraine. Russian assaults resulted in widespread damage to densely populated residential areas and critical civilian infrastructure, including power stations, transportation hubs, schools, and health care facilities. As a result, more than 10 million refugees have fled Ukraine, approximately 50% fleeing to Poland. Attacks on Ukraine's health system and pharmaceutical supply chains created challenges for the provision of critical services for people with injuries and chronic illnesses. Among the most vulnerable patients are children with cancer and blood disorders, who require timely access to diagnostic, therapeutic, and supportive care for survival. The war has resulted in acute interruption of medical care, threatening the lives of thousands of Ukrainian children.

The work describes a case of rare neonatal systemic juvenile xanthogranuloma with an initial damage of the scalp, limbs, back and abdomen, multiple damages of the parenchyma of both lungs, spleen and liver with the development of a severe form of congenital cholestatic hepatitis. The diagnosis was established on the basis of histopathological and immunohistochemical examination of the skin nodules. The child on the background of therapy under the Langerhans cell histiocytosis III program achieved a partial response, which was manifested by a reduction of granulomatous formations on the skin, elimination of liver failure, but retained hepatosplenomegaly, specific lesions of the lung parenchyma, liver, and left kidney. Against the background of cytostatic therapy, the patient developed secondary pancytopenia, perianal ulcerative-necrotic dermatitis with lesions on buttocks, stomatitis, protein-energy deficiency, acute liver failure. coagulopathy, disseminated intravascular coagulation syndrome, acute renal failure, respiratory failure of III degree, cardiovascular insufficiency of III degree, pulmonary edema, cerebral edema, cerebral coma of II-III degree, enterocolitis, intestinal paresis. Despite multicomponent intensive care, the child's condition progressively deteriorated, and the patient died. The aspects of differential diagnosis of neonatal systemic juvenile xanthogranuloma are discussed.