[Rituximab treatment for adults with steroid-resistant idiopathic thrombocytopenic purpura].

Objective: To investigate the efficacy and safety as well as the effects of rituximab on B-lymphocytes and anti-platelet glycoprotein-specific antibodies, in patients with steroid-resistant idiopathic thrombocytopenic purpura (ITP).

Methods: Twelve steroid-resistant ITP patients, 16 to 54 years old, received intravenous rituximab at the dose of 375 mg/m2 once--weekly for 4 weeks. Lab studies included CBC, serum concentrations of IgG, IgM and IgA. CD3+, CD4+, CD8+, CD19+, CD20+ cell numbers were assayed by flow cytometry and anti-platelet glycoprotein-specific antibodies (GP IIb/IIa, GP Ib/IX) were assayed by monoclonal antibody-specific immobilisation of platelet antigens prior to and following rituximab therapy.

Results: A complete response (platelet counts > or = 100 x 10(9)/L) was observed in 4 cases, a partial response (platelet counts between 50 and 100 x 10(9)/L) in 3 cases, a minor response (platelet counts between 30 and 50 x 10(9)/L) in 2 cases, and nonresponse (platelet counts < 30 x 10(9)/L) in 3 cases. Responses were sustained 0.5 to 12 months (median 5 months). After 4 weeks of rituximab therapy, anti-platelet glycoprotein-specific antibodies (GP IIb/IIIa, GP Ib/IX) disappeared except one NR patient and CD19+/ CD20+ cells were almost depleted in all patients (295.0 +/- 86.4) x 10(6)/L vs (4.1 +/- 2.2) x 10(6)/L (P < 0.01). As expected, the T cell counts, and the serum concentrations of IgG, IgM and IgA were not changed after therapy. No severe side effects were observed.

Conclusion: Rituximab may be an effective and safe treatment for adults with steroid-resistant ITP.