Improving outcomes in transplantation

Non-Hodgkin lymphoma: an update

Non-Hodgkin lymphoma (NHL) causes many deaths worldwide, and its incidence is increasing. Although some cases are associated with immunodeficiency, autoimmunity, or viral infections, in most cases the causes of NHL are not understood. However, there have been some important advances in our understanding of the development of healthy lymphocytes and the pathogenesis of NHL over the past 10 years. These advances have been accompanied by an improvement in treatment for NHL. Before the late 1990s, the only treatment option available was cytotoxic chemotherapy. In the past 10 years, however, high-dose chemotherapy and autologous stem-cell reconstitution have become established parts of treatment for aggressive lymphoma. Furthermore, monoclonal antibodies have become another therapeutic option. Rituximab (an anti-CD20 monoclonal antibody) is the most advanced monoclonal antibody in clinical trials and has become part of standard treatment for some lymphomas. Rituximab, and many other monoclonal antibodies, continue to be assessed in clinical studies. Monoclonal antibodies can be used alone or in combination with standard-dose or high-dose chemotherapy, and they can also be conjugated to radionuclides to enhance cytotoxicity. Here, we review advances in the treatment of NHL that have occurred over the past 10 years.

Rituximab: expanding role in therapy for lymphomas and autoimmune diseases

Rituximab (Rituxan) is a human-mouse chimeric monoclonal antibody that targets the B-cell CD20 antigen and causes rapid and specific B-cell depletion. Rituximab was approved in the United States in 1997 to treat low-grade or follicular, relapsed or refractory, CD20-positive B-cell non-Hodgkin's lymphoma (NHL). Since then, further clinical experience with rituximab has been incorporated into the prescribing information, which now stipulates an extended eight-week schedule, treatment of patients with refractory or relapsed bulky disease measuring >10 cm, and retreatment of patients who responded to rituximab previously. In 1998, the European Union approved rituximab (MabThera) to treat stage III/IV, follicular, chemotherapy-resistant, or relapsed NHL. Recently, the European Union also approved the use of rituximab in combination with standard chemotherapy for aggressive NHL. Many clinical trials have evaluated rituximab, alone or with other therapies, in indolent and aggressive NHL as well as other B-cell lymphoproliferative disorders. New studies are evaluating rituximab's role in first-line therapy, maintenance therapy, and stem-cell transplantation procedures. The use of rituximab against autoimmune disorders, such as rheumatoid arthritis, immune thrombocytopenic purpura, autoimmune hemolytic anemia, systemic lupus erythematosus, and multiple sclerosis, is also under investigation.

In vivo magnetic resonance imaging of immune cells in the central nervous system with superparamagnetic antibodies

We developed a novel MRI technique to image immune cell location and homing in vivo to the central nervous system (CNS). Superparamagnetic antibodies specific for cell surface markers allowed imaging of CD4+ T cells, CD8+ T cells, and Mac1+ cells in the CNS of mice infected with Theiler's murine encephalomyelitis virus (TMEV) and in mice with experimental autoimmune encephalomyelitis (EAE). Superparamagnetic antibodies have excellent T2, T2*, and good T1 relaxation properties, which makes them ideal MRI contrast materials. Immunohistochemistry of corresponding sections confirmed the specificity of the technique to detect immune cell types in the CNS. This powerful technique has potential to image any cell with unique surface antigens. Because superparamagnetic antibodies similar to those used in the study are approved for human use, the in vivo MRI technique we have described could be developed for human use.

Monoclonal antibody therapy for lymphoma

Monoclonal antibodies are an exciting advance in the treatment of lymphoma. They are safe and well-tolerated, and exhibit little cross-resistance with conventional chemotherapeutic agents. In indolent lymphomas, antibody therapy has shown useful response rates, both as first-line therapy and in relapsed disease. Follicular lymphomas appear to be particularly sensitive to rituximab, and chronic lymphocytic leukaemia to alemtuzumab. In aggressive lymphomas, the addition of rituximab to CHOP chemotherapy significantly lengthens disease-free and overall survival compared to CHOP alone as first-line therapy. Newer agents, including radiolabelled antibodies, immunotoxin-linked antibodies and antibodies against novel target antigens are showing promise in phase I and II trials in a variety of clinical settings.

Incorporating monoclonal antibodies in blood and marrow transplantation

The development of therapeutic monoclonal antibodies had been a significant advance in the treatment of B-cell non-Hodgkin's lymphoma (NHL). In the setting of blood and marrow transplantation (BMT), initial research was focused on in vitro graft purging. More recently, investigators have designed in vivo purging protocols using rituximab with the goal of obtaining tumor-free grafts. Exciting developments stem from the use of iodine 131 ((131)I)-tositumomab as well as yttrium 90 ((90)Y)-ibritumomab in myeloablative doses in blood and marrow transplantation protocols for high-risk patients. Finally, vigilance towards complications in particular unusual infections is advised given the profound immunosupressive state caused by these antibodies.

An overview of the current clinical use of the anti-CD20 monoclonal antibody rituximab

The chimeric anti-CD20 monoclonal antibody rituximab has become part of the standard therapy for patients with non-Hodgkin's lymphoma (NHL). To date, more than 300 000 patients have been treated with rituximab worldwide, including patients with indolent and aggressive NHL, Hodgkin's disease and other B-cell malignancies. Combination of rituximab with cytotoxic agents or cytokines has been explored in a number of different studies. Rituximab is now also approved for patients with diffuse large B-cell lymphoma when combined with standard CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone). The monoclonal antibody is generally well tolerated. Most adverse events are infusion-associated, including chills, fever and rigor related to the release of cytokines.