Epstein-Barr Virus–Driven Lymphoproliferation Due to Interleukin-2–Inducible T Cell Kinase Deficiency: A Case Report

Introduction Interleukin-2–inducible T cell kinase (ITK) deficiency is a rare autosomal recessive combined immunodeficiency that predisposes patients to Epstein-Barr virus (EBV) infections and severe lymphoproliferation. Early diagnosis is crucial to guide management and prevent serious complications. Case Presentation We report the case of an 11-year-old boy, born to a consanguineous marriage, with a history of autoimmune hemolytic anemia and a sister who died at the age of four from lymphoma, hospitalized for prolonged fever, weight loss, and productive cough. On clinical examination, the patient had hepatomegaly without peripheral lymphadenopathy or splenomegaly and presented with respiratory distress. Initial laboratory tests showed microcytic hypochromic anemia associated with lymphopenia. Bone marrow examination revealed no abnormalities. Blood cultures and microbiological tests for Mycobacterium tuberculosis, aspergillosis, and HIV were negative. EBV serology was discordant, with positive anti-viral capsid antigen (VCA) IgG and negative anti–Epstein-Barr Nuclear Antigen (EBNA) IgG, while blood EBV PCR was initially negative. Immunological workup revealed an expansion of double-negative T cells. Thoracic imaging showed bronchiectasis and a right basal consolidation, and abdominal ultrasound demonstrated homogeneous hepatomegaly with intra-abdominal lymphadenopathy. Despite empirical treatment for community-acquired pneumonia, the patient’s condition rapidly deteriorated, with worsening respiratory failure. Liver biopsy with EBV PCR confirmed high viral load and histopathological features consistent with lymphoma. Genetic analysis identified a pathogenic mutation in the ITK gene, confirming EBV-driven lymphoma secondary to ITK immunodeficiency. Unfortunately, the patient died before targeted therapy could be initiated. Conclusion This case highlights the development of EBV-associated lymphoma in patients carrying ITK gene mutations. Early genetic diagnosis is critical to guide therapeutic management, including consideration for hematopoietic stem cell transplantation, to reduce mortality in this rare but potentially fatal condition.