Inflammatory cytokine production in chronic active Epstein-Barr virus infection.

In order to clarify the mechanisms underlying the development of inflammation in chronic active Epstein-Barr virus infection (CABEV), we examined cytokine production using patient samples. Eleven patients were analyzed. The serum concentrations of IFN-γ, TNF-α, and IL-6 were significantly higher in patients than in healthy donors. The mRNAs of these cytokines in peripheral blood mononuclear cells were elevated in patients as compared with healthy donors. The mRNA of IFN-γ was significantly higher in patients than in healthy donors. We examined which fraction produced the cytokines in the CD4-, CD8-, and CD56-positive fractions of PBMCs. The mRNAs of IFN-γ, TNF-α, and IL-6 were highly expressed in EBV-infected cells, whereas expression was also observed in non-infected cells. We performed in vitro infection of EBV on a T-cell line, MOLT4. EBV infection enhanced the mRNA expressions of IFN-γ and TNF-α. These results suggest that the inflammatory cytokines in CAEBV are produced not only by EBV-infected but also non-infected cells. EBV itself may have roles in the cytokine production observed in infected cells.