The role of allogeneic haematopoietic progenitor cell transplantation in patients with diffuse large B-cell non-Hodgkin lymphomas (DLBCL).

Despite the undoubted improvement in the prognosis of patients with diffuse large B-cell lymphomas (DLBCLs) with the addition of rituximab in the front-line treatment, a significant proportion of patients still relapse. Salvage immune-chemotherapy followed by high-dose therapy with autologous haematopoietic cell transplantation (auto-HCT) remains the treatment of choice for such patients, especially in those who demonstrate chemosensitive disease. In recent years, allogeneic haematopoietic cell transplantation (allo-HCT) has increasingly been used for patients who are resistant to salvage treatment or relapse after an auto-HCT. Strategies using reduced intensity conditioning regimens have allowed application of this approach to a broader range of patients. PFS is up to 55% with a risk of relapse up to 80% depending on different studies. In multivariate analysis, several factors have been associated with favourable outcome including chemosensitivity of the disease, younger age and Karnofsky performance status at the time of the transplant being the strongest ones. DLIs have shown to induce durable responses in relapsed or progressed disease; however, its role remains controversial as the results are inferior to the responses seen in other haematological malignancies. More recently, the addition of MoAbs in the non-myeloablative conditioning regimens has shown encouraging results. In conclusion, allo-HCT is a feasible option in selective patients with chemosensitive DBCL, as it reduces the risk of relapse; however, this is achieved at the cost of significant non-relapse mortality.