Increased serum levels of circulating intercellular adhesion molecule 1 predict the risk of graft rejection after bone marrow transplantation for thalassemia

Beta thalassemia is a hereditary anemia curable by bone marrow transplantation (BMT), Class 3 patients have a much worse outcome with a high incidence of rejection after BMT. Adhesion molecules, including the intercellular adhesion molecule 1 are thought to play an essential role in the rejection process, To investigate whether increased levels of soluble intercellular adhesion molecule 1 (sICAM-1) may be predictive of graft rejection, the pretransplant serum concentration of sICAM-1 of 27 beta thalassemic patients who rejected the graft was compared to that of 68 beta thalassemic patients who achieved a sustained engraftment, Fifty serum samples, obtained from marrow donors, matched and sex, served as controls, beta thalassemic had significantly higher sICAM-1 concentrations as compared to controls (P = 0.0001), Significantly increased levels of sICAM-1 were found in the patients who subsequently rejected the graft (mean (95% CI) = 490 ng/ml (440; 540)) as compared to those with sustained engraftment (400 ng/ml (384; 415)), (P = 0.001), The mean level of sICAM-1 in patients with early rejection was significantly higher than that in patients with late rejection (P = 0.04), This may indicate a transfusion-mediated role of sICAM-1: some beta thalassemic patients with high sICAM-1 levels, induced by the transfusion support, mag remain immunologically active, despite the conditioning regimen, therefore such patients are likely to have an early graft rejection. Our findings indicate that sICAM-1 could be a useful indicator of immune activation in polytransfused patients with beta thalassemia who have a high risk of rejection, Determination of sICAM-1 has potential clinical implications in predicting which patients may reject after BMT.