Elevated serum HLA class I levels coincide with acute and chronic graft-versus-host disease

The ability to predict the likely occurrence of graft-versus-host-disease (GVHD) after BMT would be extremely valuable. We performed a retrospective study on the correlation between soluble HLA class I (sHLA-I) levels and GVHD in the sera of 34 patients receiving an allogeneic BMT and in the sera of 12 patients receiving an autologous BMT. sHLA-I levels measured pre- and at different times post-BMT were correlated with the occurrence of post-BMT complications, ie acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD), infections and relapse. No changes in sHLA-I levels (delta sHLA-I) occurred in autologous and allogeneic BMT patients without GVHD. In contrast, sHLA-I reached high levels in patients suffering from GVHD. Increased sHLA-I levels correlated strongly with episodes of both acute and chronic GVHD (P = 0.004 and P = 0.005, respectively). Also during relapse increased sHLA-I levels were found (P = 0.032). During infections sHLA-I levels increased, although not significantly. Kinetic studies gave no evidence that the increase in sHLA-I levels preceded the clinical occurrence of aGVHD or of cGVHD. A slight, but significant correlation was found between total blood bilirubin levels and sHLA-I levels in patients suffering from GVHD (P = 0.037), indicating the contribution of the liver as a source of sHLA-I. We conclude that measurements of sHLA-I levels do not function as a predictive parameter for GVHD, but can be valuable for the monitoring of GVHD after BMT.