Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of immune thrombocytopenic purpura (ITP)

- Diagnosis must be made according to American Society of Hematology diagnostic
guidelines by a member of Mayo Rochester's Division of Hematology/Oncology
within the past year

- ITP must be confirmed by bone marrow aspiration and biopsy in all patients ≥ 60
years of age*

- Bone marrow studies performed outside Mayo must be reviewed by a Mayo
hematopathologist to confirm diagnosis and exclude evidence of other
hematologic disorders NOTE: *Bone marrow evaluation is discretionary for
all other patients

- Requires treatment, as defined by 1 of the following parameters:

- Platelet count ≤ 30,000/mm³

- Platelet count ≤ 50,000/mm³ with episodic bleeding (i.e., spontaneous or with
minimal trauma) requiring treatment

- No concurrent diagnosis of a condition known to cause secondary immune (or nonimmune)
thrombocytopenia, including, but not limited to, any of the following:

- Rheumatological conditions, such as lupus, rheumatoid arthritis, scleroderma, or
mixed connective tissue disorder

- Patients with positive serologies and no concurrent, clinically evident
condition are eligible

- HIV positive or AIDS

- Non-Hodgkin's lymphoma, Hodgkin's lymphoma, chronic lymphocytic lymphoma,
multiple myeloma, or other malignant hematological conditions

- Clinically evident antiphospholipid antibody syndrome* or heparin-induced
thrombocytopenia

- Clinically overt liver disease, hepatitis B surface antigen positive, hepatitis
C serology positive, or evidence of a microangiopathic hemolytic anemia, such as
disseminated intravascular coagulation, hemolytic-uremic syndrome, thrombotic
thrombocytopenic purpura, or preeclampsia NOTE: *Positive laboratory tests
without the defined clinical criteria for a diagnosis of antiphospholipid
antibody syndrome is allowed

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Creatinine ≤ 2 times upper limit of normal (ULN)

- Direct bilirubin ≤ 1.5 times ULN

- Total bilirubin ≤ 1.5 times ULN

- AST ≤ 2.5 times ULN

- Hemoglobin ≥ 10 g/dL

- WBC ≥ 3,000/mm³

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No hypersensitivity to murine or chimeric proteins

- No other disease, metabolic dysfunction, physical examination finding, or clinical
laboratory finding giving reasonable suspicion of a disease or condition that
contraindicates the use of an investigational drug or that may affect the
interpretation of the results or render the patient at high risk for treatment
complications

- Able to take a proton-pump inhibitor while on corticosteroids

- No unresolved or incompletely treated infection within the past 14 days

PRIOR CONCURRENT THERAPY:

- No prior corticosteroid therapy since the diagnosis of ITP

- Corticosteroid therapy is allowed for up to 14 days prior to study entry, once
the baseline CBC has been established

- No prior rituximab

- No other concurrent therapy for ITP, including androgens, IV immunoglobulins, RH_o
(D) immune globulin, cyclosporine, or azathioprine sodium