Rituximab as Second Line Treatment for ITP

Inclusion Criteria: 1. ITP with platelet count \<30 x 109 /l after 2 weeks of treatment with prednisolon or during prednisolon tapering period i.e. from week three of prednisolon initiation. Patients with platelet count between 30 -50 are eligible if a higher platelet count is considered necessary, because of : concomitant medical illness predisposing to bleeding (hypertension, GI bleeding, bleeding diathesis, previous history of bleeding) concomitant medical condition requiring platelet blocking agents/ anticoagulation, persistent bleeding despite platelets \> 30 x 109 /l, prior to surgery, or because of other patient related factors necessitating higher platelet count as occupation, hobby, psychological intolerability. 2. Subject is \>18 years 3. Subject has signed and dated written informed consent. 4. Subject is able to understand and comply with protocol requirements and instructions, and intends to complete the study as planned. 5. Females in fertile age should express willingness for use of contraceptive means for 6 months following the administration of the study drugs. Exclusion criteria: 1. Previous splenectomy, chemotherapy, treatment with anti-D Ig, rituximab, or immune-suppressive treatments other than corticosteroids, Dapsone or Danazol 2. Underlying malignancy or previous history of malignancy in the past 5 years (except skin carcinoma) 3. Pregnancy and lactation 4. Not willing to participate in the study 5. Expected survival of \< 2 years 6. Known intolerance to murine antibodies 7. Females in child-bearing age not willing to use contraception for 6 months 8. HIV-positive/AIDS-, Hepatitis -B virus positive- or Hepatitis -C virus positive 9. Patients with a definite Systemic Lupus Erythematosus (SLE) (\> 4 of the American College of Rheumatology Criteria) 10. Patients currently involved in another clinical trial with evaluation of drug treatment 11. Bacterial infections, viral infections, fungal infections, myco-bacterial infections (excluding fungal infections) or other evolutive infections or any other infections episode requiring hospitalisation or treatment with an antibiotics 4 weeks before selection for IV route or within 2 weeks before selection for oral route 12. History of soft tissue, bone or joint infections (fascitis, abscess, osteomyelitis, septic arthritis) during the last year prior to inclusion in the study 13. Medical history of relapsing or chronic severe infectious diseases or any other underlying pathology predisposing to serious infections 14. Known Primary or secondary immune deficiency syndromes 15. Administration of a living vaccine within 4 weeks preceding the inclusion in the study -16- Previous treatment with any lymphocytes depleting medication (e.g.: MabCampath®) 17- Previous treatment with inhibitors of leucocytes transmigration (e.g.: Tysabri®) 18- Known intolerance to human monoclonal antibodies 19- Known severe chronic pulmonary obstructive Disease (FEV \< 50% or functional dyspnoea grade 3) 20- Known congestive heart failure NYHA (New York Heart Association classification of heart failure) class III and IV 21- Recent episode (\<6 months) of acute coronary syndrome.