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 transpl antation (BMT), Class 3 patients have a much worse outcome with a high incidence of rejection after BMT. Adhesion molecules, including the i ntercellular 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 o f 27 beta thalassemic patients who rejected the graft was compared to that of 68 beta thalassemic patients who achieved a sustained engraftm ent, 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 i ncreased 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 = 0.00 1), The mean level of sICAM-1 in patients with early rejection was sig nificantly 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 transfus ion support, mag remain immunologically active, despite the conditioni ng regimen, therefore such patients are likely to have an early graft rejection. Our findings indicate that sICAM-1 could be a useful indica tor of immune activation in polytransfused patients with beta thalasse mia who have a high risk of rejection, Determination of sICAM-1 has po tential clinical implications in predicting which patients may reject after BMT.