Saliva and blood interferon gamma levels and IFNG genotypes in acute graft-versus-host disease.

Objective:  Graft-versus-host disease is a major complication after allogenic hematopoietic stem cell transplantation. Interferon gamma is an important pro-inflammatory cytokine involved in this disease. Cytokine gene polymorphisms are associated with functional differences in cytokine expression and can alter the clinical course of graft-versus-host disease. This study aimed to investigate the association between IFN-γ levels in saliva, blood, and IFNG polymorphisms, as well as the occurrence of acute graft-versus-host disease in allogenic HSCT.
Subjects and Methods: Fifty-eight consecutive allogenic hematopoietic stem cell transplantation recipients and their donors were prospectively studied. IFN-g levels in saliva and blood were assessed by ELISA. Samples were collected weekly from 7 days before transplantation (day -7) to 100 days after allogenic HSCT (day +100) or until death. Saliva and/or blood samples were obtained from the recipients and donors to determine IFNG gene polymorphisms.
Results:   Increased saliva and blood IFN-g levels were observed in patients that had developed aGVHD. In the saliva, the peak levels of IFN-g could be found one week before aGVHD diagnosis, while in the blood, peak levels of IFN-g could be only observed upon diagnosis. A significant association could be identified between the recipients'IFNG genotypes and the IFN-g levels in their blood, at +14 days after HSCT. No association could be observed between IFNG gene polymorphisms and the aGVHD.
Conclusion:  The present study shows that the genetic background of recipients can influence the production of IFN-g. Moreover, as IFN-g levels in the saliva and blood were found to be associated with aGVHD development, this cytokine may be a useful predictor of acute graft-versus-host disease.
(© 2012 John Wiley & Sons A/S.)