Thrombocytopenia and Bleeding in Wiskott-Aldrich Syndrome (WAS) Patients

Inclusion Criteria: In order to be eligible for study entry, subjects must comply with the following: * Males from 3 months old to 80 years old * Signed written informed consent obtained prior to study entry * Clinical diagnosis of WAS or XLT * Platelet levels less than 100 x 109/L * Adequate renal and hepatic function (creatinine and bilirubin less than or equal to 1.5 x IULN, AST and ALT less than or equal to 2.5 x IULN) Exclusion Criteria: Any patient is ineligible for study entry if he/she: * Over the age of 80 * Women (only males are eligible) * fertile men who are not practicing or who are unwilling to practice birth control while enrolled in the study or until at least 6 months after treatment * Aspirin, aspirin-containing compounds, salicylates, non-steroidal anti-inflammatory medications (NSAIDS), clopidogrel or ticlopidine, warfarin or other vitamin K antagonists, unfractionated or low molecular heparin within 7 days of first infusion * Red blood cell transfusion in the past four weeks * Elevated (\> 1.5 x ULN) prothrombin time (PT) or partial thromboplastin time (PTT) * New York Heart Classification III or IV heart disease. Other severe cardiovascular or cardiopulmonary disease, including COPD. * Known HIV infection, hepatitis B or C infection * Any infection requiring antibiotic treatment within 3 days * Other concurrent medical or psychiatric conditions that, in the Investigator's opinion, may be likely to confound study interpretation or prevent completion of study procedures and follow-up examinations. * Prior malignancy with less than a 5-year disease-free interval, excluding nonmelanoma skin cancers and carcinoma in situ of the cervix