B lymphocyte

Novel applications of Rituximab in dermatological disorders

Rituximab is a monoclonal therapeutic anti-CD20 antibody that has been approved for use in lymphoma and rheumatoid arthritis. Over the past decade several reports based on case series and observational studies have recorded the benefits of rituximab in particular groups of dermatological patients. Off-label use of rituximab in many dermatological indications is not uncommon in many countries in the world. This article reviews the available data that may be of use to the practicing dermatologist. Because of its potential complications, paucity of clinical data, and cost considerations, rituximab is favoured only when standard systemic therapies fail or corticosteroids are absolutely contraindicated. Further research is required in this field.

Successful treatment with rituximab in a patient with TTP secondary to severe ANCA-associated vasculitis

We report a case of thrombotic thrombocytopenic purpura (TTP) secondary to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis treated by rituximab. TTP secondary to ANCA-associated vasculitis is very rare and has a high mortality rate. We employed rituximab and successfully treated TTP secondary to ANCA-associated vasculitis, because standard therapies, such as steroid therapy, intravenous pulse cyclophosphamide, and repeated plasma exchange (PE), did not suppress her disease activity. This is the first report to suggest that rituximab can achieve complete remission of TTP secondary to ANCA-associated vasculitis.

Two cases of refractory thrombotic thrombocytopenic purpura associated with collagen vascular disease were significantly improved by rituximab treatment

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder of small vessels. TTP is associated with deficiency of the von Willebrand factor-cleaving protease, ADAMTS13, and its inhibitor. Low ADAMTS13 activity is present in most of idiopathic TTP patients. The prognosis of TTP was improved by plasma exchange treatment, which replaces the ADAMTS13 and removes ADAMTS13 inhibitor. However, ADAMTS13 activity is normal in some TTP patients. These are found among the secondary TTP patients associated with collagen disease, hematopoietic stem cell transplantation, malignancy, or drugs. In addition, most of them do not respond to plasma exchange. On the other hand, several reports demonstrated that rituximab, which is an anti-CD20 monoclonal antibody, is effective for refractory TTP cases caused by ADAMTS13 deficiency. It is considered that the effect of rituximab is associated with disappearance of ADAMTS13 inhibitor. However, rituximab therapy was effective for the TTP patients with normal ADAMTS13 activity in our cases. We considered another mechanism of rituximab for TTP cases.