Haema 2010; 1(2): 195-203
by Stavroula Masouridi MD and Photis Beris MD.
University Hematology Clinic, Laikon General Hospital, School of Medicine, National and Kapodistrian University of Athens – Greece.
Abstract
Rituximab is used in the last 10 years in corticosteroid-resistant primary immune thrombocytopenia (ITP) with a total response of 60-70%. However the majority of patients will not achieve a long term response. Concerning the mechanism of action of Rituximab we believe that there is inhibition in the production of autoantibodies and Rituximab favors also reconstitution of T-lymphocyte disorders present in ITP. Significantly lower doses from those used in lymphomas appear to have similar results. Its relatively safe profile makes rituximab an attractive second-line therapeutic option as compared to splenectomy in certain cases. Anti-CD52 monoclonal antibody was shown to be effective in certain forms of refractory autoimmune cytopenias, mainly in autoimmune hemolytic anemia, autoimmune neutropenia and pure red cell aplasia. Up to date clinical experience does not allow considering anti-CD52 as an alternative solution in case of refractory ITP. In vitro and clinical studies with the anti-CD40L monoclonal antibodies have shown the immunosuppressive effect not only in T helper lymphocytes but also in B autoreactive cells. Clinical studies have shown that a total of 11 (24%) out of 46 patients with refractory ITP treated with anti-CD40L monoclonal antibodies responded positively. We believe that phase III clinical studies are actually mandatory if we want to have strong evidence that these antibodies with almost no serious side effects can get the green light to enter our armatorium for patients with refractory or relapsing ITP.