MCMV Infection Lowers the Threshold for the Development of Clinical GvHD After Allogeneic Bone Marrow Transplantation

The study investigated the impact of MCMV infection on the development of GvHD after allogeneic bone marrow transplantation using a mouse model. It was found that MCMV infection led to generalized immune activation, increasing the number of donor-derived allo-reactive T cells and GvHD activity. Mice receiving untreated donor splenocytes developed GvHD, characterized by weight loss and higher mortality, while those receiving Amotosalen-treated splenocytes showed more gradual T-cell expansion and sustained lymphoid reconstitution. The study concluded that CMV infection caused extensive expansion of allo-reactive T cells in GvHD+ mice, damaging the spleen and thymus microenvironment. Effective prophylaxis and treatment of GvHD in clinical transplantation would likely require addressing the immuno-suppressive effects of CMV infection.