Adaptation of Coagulation and Fibrinolysis in Allogeneic Stem Cell Transplantation.

Allogeneic stem cell transplantation (SCT) seems to result in activation of coagulation and fibrinolysis. We characterised the outcome of SCT and graft versus host disease (GvHD) in association with the adaptive mechanisms of coagulation and fibrinolysis. 30 patients given myeloablative conditioning with cyclophosphamide and total body irradiation underwent allogeneic SCT for a hematological malignancy. 19 patients received the transplant from a sibling and 11 from an unrelated donor. GvHD prophylaxis consisted of cyclosporine and methotrexate, and in addition methylprednisolone in case of a sibling donor. Eight patients developed GvHD during the 3-month follow-up. Several coagulation and fibrinolysis activities were serially assessed: antithrombin, protein C (PC), FVIII, prothrombin fragments 1+2 (F1+2), D-dimer, tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI-1). During the conditioning therapy as an early sign of thrombin generation, F1+2 increased 3-fold and D-dimer 4-fold, compatible with enhanced fibrin turnover. The activity of tPA reached its maximum already before the engraftment and that of PAI-1 diminished accordingly. FVIII increased steadily from normal to reach maximum (up to 273% ±104%, median ±SD, p<0.001) after engraftment. Interestingly, the natural anticoagulant, PC rose (up to 189% ± 63%) in parallel with FVIII, but showed a 5-fold individual variability. After the engraftment the FVIII, PC and antihrombin levels were highly interrelated. Clinically relevant prognostic association was observed between early low PC activity and the appearance of GvHD: the level of PC lower than 90% during the conditioning therapy was associated and even predicted (p=0.007) acute GvHD (OR=16.7). After the transplantation the level of F1+2 over 2.5 nmol/l associated and predicted the non-relapse mortality (p=0.024). Three patients with the largest early thrombin generation all died during a longer follow-up (6–24 months). Also, elevated PAI-1 activity (>10 U/ml) predicted the non-relapse mortality (p=0.013). In conclusion, early activation of coagulation and fibrinolysis is followed by increased FVIII and PC activities in SCT. Early marked thrombin generation and elevated PAI-1 associated with the non-relapse mortality and low PC activity with the appearance of acute GvHD.