Ultimately, six variables were identified to have the greatest effect on distinguishing LA-HLH among HLH patients with EBV infection: SUVmax-lymph nodes/Mediastinum, IFN-γ, EBV-DNA in plasma, SUVmax-extranodal lesions/Mediastinum, SUVmax-bone lesions or bone marrow/Mediastinum, and β2-microglobulin. The gene discussed is IFNG; the disease is Epstein-Barr virus infection.