Background: Graft rejection is a major complication of lung transplantation. No serological marker of rejection is in common use. Hepatocyte growth factor (HGF) is highly expressed in the lung and produced after acute lung injury; serum concentrations increase in inflammatory lung diseases. We investigated whether HGF could be an accurate marker for prediction of lung-graft rejection.
Methods: Serum concentrations of HGF were measured by ELISA in 109 patients who had undergone lung transplantation (65 for chronic obstructive pulmonary disease; 23 for cystic fibrosis; 21 for idiopathic lung fibrosis), comparing those who had no subsequent events and those with episodes of infection or rejection, as well as in 12 healthy controls.
Findings: The mean baseline serum HGF concentration was 645 ng/L (SD 259) in controls and 1358 ng/L (603) in the patients before transplantation. After transplantation the mean concentration in patients with no events was 1147 ng/L (510) compared with 1559 ng/L (323) in patients with infection (p=0.001 vs controls; change from pretransplant value not significant). Patients with rejection had significantly higher concentrations than all other groups (3972 ng/L [1463], p<0.0001). Logistic regression identified HGF as a predictor for lung graft rejection (p=0.012). After steroid treatment, HGF concentrations returned almost to the preoperative values within 3 days.
Interpretation: HGF might be a marker for graft rejection in lung transplantation. A potential link between viral infection, mainly cytomegalovirus, and HGF, however, remains to be investigated.