Allogeneic stem cell transplantation from related and unrelated donors for aplastic anaemia in adults—a single-centre experience

How I treat acquired aplastic anemia

Survival in severe aplastic anemia (SAA) has markedly improved in the past 4 decades because of advances in hematopoietic stem cell transplantation, immunosuppressive biologics and drugs, and supportive care. However, management of SAA patients remains challenging, both acutely in addressing the immediate consequences of pancytopenia and in the long term because of the disease's natural history and the consequences of therapy. Recent insights into pathophysiology have practical implications. We review key aspects of differential diagnosis, considerations in the choice of first- and second-line therapies, and the management of patients after immunosuppression, based on both a critical review of the recent literature and our large personal and research protocol experience of bone marrow failure in the Hematology Branch of the National Heart, Lung, and Blood Institute.

A closer look at paroxysmal nocturnal hemoglobinuria

Knowledge of the molecular mechanisms leading to the paroxysmal nocturnal hemoglobinuria (PNH) phenotypes has substantially increased in the past two decades. The associated intravascular hemolysis, hypercoagulablilty, and bone marrow failure result in a wide range of clinical sequlae. Although treatment has usually been symptomatic through several modalities and rarely curative through hematopoietic cell transplantation, recent development of the novel targeted therapeutic agent eculizumab has offered new promises for this highly morbid and fatal disease. This review summarizes current knowledge of the pathophysiology, diagnostic modalities, clinical implications, and treatment approaches of patients with PNH.

Ex vivo expansion and long-term hematopoietic reconstitution ability of sorted CD34+CD59+ cells from patients with paroxysmal nocturnal hemoglobinuria

Autologous bone marrow transplantation (ABMT) for paroxysmal nocturnal hemoglobinuria (PNH) remains difficult so far. To expand residual normal CD34(+)CD59(+) cells isolated from patients with PNH and observe the long-term hematopoietic reconstruction ability of the expanded cells both ex vivo and in vivo, CD34(+)CD59(+) cells from 13 PNH patients and CD34(+) cells from 11 normal controls were separated from bone marrow mononuclear cells first by immunomagnetic microbeads and then by flow cytometry autoclone sorting. The cells were then cultivated under different conditions. The long-term hematopoietic supporting ability of expanded CD34(+)CD59(+) cells was evaluated by long-term culture in semi-solid medium in vitro and long-term engraftment in irradiated severe combined immunodeficiency (SCID) mice in vivo. The best combination of hematopoietic growth factors for ex vivo expansion was SCF + IL-3 + IL-6 + FL + Tpo + Epo. The most suitable time for harvest was on day 7. CD34(+)CD59(+) PNH cells retained strong colony-forming capacity even after expansion. The survival rate, complete blood cell count recovery on day 90, and human CD45 expression in different organs were similar between the irradiated SCID mice transplanted with expanded CD34(+)CD59(+) PNH cells and those with normal CD34(+) cells (P > 0.05) both in primary and secondary transplantation. These data provided a new potential way of managing PNH with ABMT.

[Hematopoietic stem cell transplantation. Indications, foundations and perspective]

The hematopoietic stem cell transplantation (HSCT) has become a standard therapy for many inherited and acquired disorders of the bone marrow and immune system. Autologous HSCT is mainly done as part of the primary therapy in multiple myeloma and as part of relapse therapy in malignant lymphoma. In contrast, allogeneic HSCT is predominantly performed in patients with acute leukemias. The selection process for allogeneic HSCT takes disease-specific as well as patient-specific factors into account. Risk factors which can predict for poor response to chemotherapy can now be identified in acute myeloid as well as lymphoid leukemia, based on phenotype, cytogenetics, molecular genetics and response to therapy. In these patients allogeneic HSCT can improve overall survival from 0-20% to 30-60%. New conditioning protocols have now raised the upper age limit for transplantation to 70 years. In elderly patients the selection of patients based on absence of comorbidities becomes especially important. The increasing number of long-term survivors requires knowledge of organ-specific late toxicities including secondary malignancies.