Clinicopathological findings of virus-associated hemophagocytic syndrome in bone marrow: Association with Epstein-Barr virus and apoptosis

Non-neoplastic hemophagocytic syndrome (HPS), also called virus-associated hemophagocytic syndrome (VAHS), has been thought to be a distinct clinical entity. A spontaneous recovery is common, but the prognosis of Epstein-Barr virus (EBV)-associated VAHS is poor. However, the role of EBV has yet to b e clearly elucidated, A retrospective study of the bone marrow of 30 cases, in which the diagnosis of non-neoplastic VAHS was clinicopathologically co nfirmed, was performed. We were unable to histologically confirm the presen ce of neoplastic lesions, especially lymphoma cell infiltration. Ten of the patients were children (aged less than 15 years) and young adults (aged un der 20 years; median age, 10 years). Twenty patients were adults (aged over 21 years; median age, 48 years), Twelve of these patients died, while 18 s howed a spontaneous recovery. We performed immunological staining and in si tu hybridization (ISH) for EBV, To clarify the presence of apoptosis, an in situ apoptosis detection (tunnel) method was used, In situ hydridization s howed an EBV-presence in 16 of the 30 patients. In addition, the EBV-presen ce was confined in the lymphocytes, especially T lymphocytes in double stai nings, The number of EBV-infected cells varied; however, the EBV presence w as associated with ages, Nine of the 10 children and young adults showed an EBV-presence, while EBV was detected in seven of the 20 adults, Especially in 10 patients aged over 49 years, no EBV was detected, According to the i n situ apoptosis detection, apoptotic cells were increased in number and co nsidered to be lymphoid cells, but not myeloid or histiocytic cells. Some a poptotic cells were phagocyted with histiocytes. Histologically, apoptosis may be one of the factors that induced phagocytosis.