Immunosuppressive therapy alleviates murine cytomegalovirus recurrence by reducing TNF-α post cell transplantation with lethal GVHD.

Cytomegalovirus (CMV) reactivation leads to obvious morbidity and mortality in patients after allogeneic hematopoietic cell transplantation (allo-HCT). Current immunosuppressive therapy reduces the frequency of graft-versus-host disease (GVHD), and is generally accepted as a high risk factor for viral recurrence. In the present study, we investigated the influence of cyclosporin A (CsA) and rapamycin (RAPA), two commonly used immunosuppressive agents, on murine cytomegalovirus (MCMV) recurrence by two allo-HCT models: one with mild and one with severe GVHD. In models with mild GVHD and partial immune recovery, transplanted mice with CsA and RAPA showed a higher viral load and impaired CMV-specific immune recovery compared to those with placebo. In contrast, in HCT models with severe GVHD, groups treated with immunosuppressive therapy showed alleviation of viral recurrence as well as GVHD-related symptoms. In addition, no CMV-specific immune reconstitution was found in any group, implying immunosuppressive therapy was not relevant to antiviral response. Furthermore, a significant correlation between MCMV DNA copies and tumor necrosis factor alpha (TNF-α) was found, and recipients with immunosuppressive therapy showed a lower level of TNF-α. Finally, using lenalidomide (an inhibitor of TNF-α), a lower viral load was found in animals with lenalidomide. Having received lenalidomide, recipients showed no statistical difference in viral load between groups with and without immunosuppressive therapy. Taken together, we provide evidence of the dual effect of immunosuppressive therapy on viral reactivation. Importantly, we found that immunosuppressive therapy had the ability to alleviate viral load by reducing TNF-α in a mouse model with severe GVHD.