Tehran University of Medical Sciences Immunology and Genetics Journal 2645-4831 8 4 2025 07 20 374 377 Elena Kishkurno Department of Pediatric Infectious Diseases with Advanced Training Courses and Retraining, Belarusian State Medical University, Minsk, Belarus Tamara Amvrosieva State Institution «Republican Center for Hygiene, Epidemiology and Public Health», Minsk, Belarus Evgeniy Dmitriev Republican Center of the Pathology of Gemostasis, Belarusian Research Center for Pediatric Oncology, Hematology and Immunology, Minsk, Belarus Katerina Divakova Department of Pediatric Infectious Diseases with Advanced Training Courses and Retraining, Belarusian State Medical University, Minsk, Belarus 2025 06 06 2025 07 20 The peculiarity of the chromosomally integrated form of human herpesvirus type 6 (ciHHV-6) is its wide distribution (up to 1% of the population), the possibility of transmission by inheritance, the problem of diagnosis, including issues of differential diagnosis with the acute form of HHV-6 infection, which, in turn, makes it difficult to resolve the problem of the therapy necessity. In addition, activation of ciHHV-6 is possible sometimes with acute infection clinical symptoms and the need for antiviral therapy, especially in patients after bone marrow transplantation and chemotherapy. We report a 10-years-old girl after chiasmal-sellar germinoma surgery and subsequent chemotherapy with ciHHV-6B. The child was treated with ganciclovir. This did not significantly influence the reduction of the viral load HHV-6B DNA in serum and cerebrospinal fluid. No adverse effects of antiviral treatment were registered. It’s important to exclude ciHHV-6 before the diagnosis of HHV-6 active disease is made, as this screening may prevent the unnecessary use of antivirals. https://igj.tums.ac.ir/index.php/igj/article/view/211 https://igj.tums.ac.ir/index.php/igj/article/download/211/200