Immunohematology

Rituximab treatment for chronic refractory idiopathic thrombocytopenic purpura

Idiopathic thrombocytopenic purpura (ITP) is characterized by mucocutaneous bleeding and a low platelet count caused by increased autoantibodies against self-antigens and T-cell mediated cytotoxicity. About 10-30% patients with ITP will become refractory ITP. Most of them will become refractory to corticosteroids and splenectomy, as well as other available agents such as intravenous immunoglobulins, danazol, or chemotherapy. B cells not only are the passive producers of immunoglobulins, but also play an important immunoregulatory role in pathophysiology of ITP. Rituximab, a chimeric anti-CD20 monoclonal antibody that specifically targets the CD20 molecule on the B-cell surface, is useful in the treatment of ITP through B cells depletion. Rituximab has multiple mechanisms of inducing cytotoxicity in vivo, including antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), direct apoptosis signaling, and possible vaccine effects. In most clinical reports, rituximab was given as an intravenous infusion at a dose of 375 mg/m(2) weekly for four doses. A total complete response (CR) of 33.2% and a total response of 52.9% were reported. Most results found that no clinical or laboratory parameters could predict treatment outcome. Though the infusion-related side effects of rituximab were common in ITP, it was well tolerated with rare severe side effects. In general, rituximab appears to be a promising immunotherapeutic agent for the treatment of refractory ITP. More controlled clinical trials are necessary to evaluate both the efficacy and long-term safety of the drug.

Rituximab and its role as maintenance therapy in non-Hodgkin lymphoma

Since rituximab, a chimeric monoclonal anti-CD20 antibody, was introduced into clinical practice in 1997, data regarding its benefit in terms of response rate, quality of response, progression-free survival and overall survival in B-cell lymphoid malignancies continues to expand. Rituximab has proven to be a relatively well-tolerated drug, with its major side effects being infusion related. Rituximab was approved initially by the US FDA and the European Medicines Agency for relapsed or refractory low-grade or follicular CD20+ B-cell non-Hodgkin lymphomas. Subsequently, its use has been extended to include first-line therapy in low-grade lymphoma as well as the treatment of more aggressive histological subtypes such as diffuse large B-cell lymphoma. In this article, we review the landmark trials that have impacted clinical practice in follicular and diffuse large B-cell lymphomas and the emerging data for use of rituximab as maintenance therapy in non-Hodgkin lymphoma.

Update on the treatment of lupus nephritis

Lupus nephritis (LN) is a major cause of morbidity and mortality in patients with systemic lupus erythematosus. Although the use of aggressive immunosuppression has improved both patient and renal survival over the past several decades, the optimal treatment of LN remains challenging. Improved outcomes have come at the expense of significant adverse effects owing to therapy. Moreover with long-term survival, the chronic adverse effects of effective therapies including risk of malignancy, atherosclerosis, infertility, and bone disease all become more important. Finally, some patients fail to achieve remission with standard cytotoxic therapy and others relapse when therapy is reduced. For these reasons, recent clinical trials have attempted to define alternate treatment protocols that appear to be efficacious in achieving and maintaining remission, but with less toxicity than standard regimens. This paper discusses established and newer treatment options for patients with proliferative and membranous LN, with an emphasis on the results of these recent clinical trials. We also review the experimental and human data regarding some of the novel targeted forms of therapy that are under investigation and in different phases of clinical trials.

Successful treatment of autoimmune hepatitis and idiopathic thrombocytopenic purpura with the monoclonal antibody, rituximab: case report and review of literature

Rituximab, a chimeric monoclonal anti-CD20 antibody, has shown activity in several autoimmune disorders. We describe a case of a 52 years old female who was diagnosed with idiopathic thrombocytopenic purpura and concomitant autoimmune hepatitis (AIH), both non-responsive to steroids. She was subsequently treated with rituximab, which resulted in a rapid increase in her platelet count and an unexpected normalization of her hepatic biochemical tests. Both her platelet count and her hepatic biochemical tests remained normal for over 5 months. In this case, rituximab showed an impressive clinical response for the treatment of AIH, and it may be considered as an alternative treatment in patients who do not respond to corticosteroid therapy. Prospective randomized studies in AIH are needed to validate this observation.