Summary:We studied occurrence, risk factors and outcome of patients with transplant-associated microangiopathy (TAM) after allogeneic stem cell transplantation (HSCT). A total of 221 consecutive patients were transplanted between 1995 and 2002. TAM is defined as evidence of hemolysis and schistocytes in the first 100 days. Outcomes analyzed included TAM and overall survival. Of 221 patients, 68 had TAM. The cumulative incidence was 31 (25-38)% at 100 days. Patients with TAM had higher LDH, higher bilirubin, higher creatinine and more often neurologic symptoms. TAM was not associated with stem cell source, cyclosporine levels and was not more frequent in recent years. In multivariate analysis, risk factors for TAM included donor type, age, gender, ABO-incompatibility and acute graft-versus-host disease (aGvHD). In patients with TAM, 1-year survival was lower than in patients without TAM (27718% for TAM with high schistocyte counts; 53715% for TAM with low schistocyte counts; vs 7877% in patients without TAM; Po0.0001). TAM was independently associated with mortality adjusting for donor type, age and aGvHD occurrence and severity. TAM is frequent after HSCT and is associated with mortality even after adjustment for aGvHD grade. Risk factors of TAM are similar to aGvHD. TAM may represent endothelial damage driven by donor-host interactions.

Patients with refractory/relapsing lymphoma are rarely cured by chemotherapy. High-dose chemotherapy (HDC) for tumor debulking followed by reduced-intensity conditioning (RIC) hematopoietic stem-cell transplantation (HSCT) has been advocated as a concept. We previously treated 10 patients (group A) with BEAM chemotherapy followed by delayed RIC HSCT at day 28. We now report on the subsequent 11 patients receiving BEAM followed immediately by fludarabine/total body irradiation and allogeneic HSCT (group B), and compare the outcome to group A patients. Non-hematological toxicity before engraftment was comparable, only gut toxicity was higher in group B. Days in aplasia, days on antibiotics and length of hospital stay were significantly longer in group A. Cumulative incidence of acute (GvHD) >or=grade II and incidence of chronic GvHD were lower in group B. At last follow-up, seven patients in group A were alive, with six of them in complete remission. In group B, nine patients were alive, seven of them in complete remission. No significant difference in estimated 3-year overall survival was seen. These data challenge the initial concept of debulking first and delaying allogeneic RIC HSCT. Allogeneic HSCT with standard BEAM conditioning is a valid alternative for patients with resistant/relapsed lymphoma, which might be considered earlier in the disease course.