Proceedings of the International scientific and practical conference ―Modern Science: Challenges and Perspectives‖ (February 9-11, 2026) / Publisher website: www.naukainfo.com. - London, United Kingdom, 2026. - 121 p.

102 hypogammaglobulinemia; suspected common variable immunodeficiency; and B-cell non-Hodgkin lymphoma [1,2]. The role of EBV in the development of certain lymphomas and neoplastic diseases (B-, T-, and NK-cell lymphomas, as well as epithelial and mesenchymal malignancies) has been well established [3], and these conditions are increasingly diagnosed in patients without overt immunodeficiency. EBV is known to exhibit tropism for B-, T-, and NK cells and may also infect monocytes/macrophages, neutrophils, the epithelium of the nasopharyngeal mucosa, and salivary gland ducts. Two stages of EBV infection are distinguished: the replicative (lytic) and latent phases. During the replicative phase, EBV genes induce the production of proteins that facilitate evasion of the host immune response [3,4]. Lymphoproliferative disorders develop as a result of complex interactions between EBV, immunogenetic factors, and environmental influences, often in the setting of immunodeficiency (e.g., HIV infection or organ and tissue transplantation) [4]. Aim of the study: To investigate the clinical and anamnestic features of the course of chronic EBV infection, its serological and virological markers, as well as the results of instrumental, histological, and immunohistochemical examination of a lymph node biopsy, using a clinical case at high risk for the development of an EBV- associated lymphoproliferative disorder in a child with generalized persistent LAP, with the aim of increasing awareness among physicians of various specialties. Materials and methods. Data from the outpatient medical records and inpatient charts of a female patient treated in the Department of Oncohematology and Intensive Chemotherapy of the Municipal Non-Profit Enterprise ―Ivano-Frankivsk Regional Children’s Clinical Hospital of the Ivano-Frankivsk Regional Council‖ were analyzed. Patient follow-up included clinical and anamnestic assessment; laboratory investigations (complete blood count, biochemical blood test, coagulation profile, serological and molecular-genetic tests); instrumental examinations (ECG, ultrasound); microbiological studies; and pathomorphological methods (histological and immunohistochemical examination of lymph node biopsy specimens). The study was approved by the Ethics Committee of Ivano-Frankivsk National Medical