Increased serum levels of matrix metalloproteinase-9 in acute graft-versus-host disease after allogeneic haematopoietic stem cell transplantation

Matrix metalloproteinases (MMPs) have been implicated in a variety of normal and pathological conditions that involve matrix degradation and remodelling. We investigated the role of MMPs in acute graft-versus-host disease (aGVHD) in 29 patients who had undergone allogeneic haematopoietic stem cell transplantation. The present study showed that the serum levels of MMP-9, but not those of MMP-2, significantly correlated with the occurrence and severity of aGVHD. Moreover, immunohistochemical analysis of the cutaneous lesions of patients with aGVHD revealed an increased number of inflammatory cells positive for MMP-9. These results suggest that MMP-9 might play an important role in the pathogenesis of aGVHD.