Abstract: Objective: To investigate the expression and significance of Smad2, 3, 4, and 7 in plasma of patients with oral chronic graft versus host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation. Methods: 18 patients with oral cGVHD after allogeneic hematopoietic stem cell transplantation were selected as oral cGVHD group and recorded with the oral characterization score and VAS. 18 patients without oral cGVHD after transplantation were recruited as no-oral cGVHD group, and 18 healthy volunteers were selected as healthy controls. Three groups of blood were collected and the expressions of protein levels of Smad2, Smad3, Smad4, and Smad7 in plasma were detected by ELISA. Results: The protein levels of Smad2 [(78.00±13.53)ng/L] and Smad4 [(484.71±90.86)ng/L] in plasma of the oral cGVHD group were higher than those of the healthy controls (P<0.05), and the expression of Smad3 [(95.15±37.32)ng/L] protein was lower than that of the healthy controls (P<0.05). There was no significant difference in the expression of Smad7 protein in these two groups (P>0.05) Compared with non-oral cGVHD group, oral cGVHD group had lower expression of Smad3 protein and higher expression of Smad2 and Smad7 protein (P<0.05). Conclusion: Abnormal expression of Smads protein in plasma may be involved in the occurrence of oral cGVHD

Key words: allogeneic hematopoietic stem cell transplantation , oral graft versus host disease , Smads