Paired Marrow Aspirations to Assess Assays in Sensitized Renal Allograft Recipients

Inclusion criteria. * Pre or post renal transplant recipients. * Renal transplant donors. * Those who give voluntary written informed consent before performance of any study-related procedures, which are not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care. Exclusion criteria. * Any patient currently receiving systemic anticoagulation therapy with heparin or coumadin. * Patient has a platelet count of \<30 x 10(9)/L within 14 days before enrollment. * Patient has an absolute neutrophil count of ANC\<1.0 x 10(9)/L within 14 days before enrollment. * Patient has received other investigational drugs within14 days before enrollment. * Serious medical or psychiatric illness likely to interfere with participation in this clinical study. * Diagnosed or treated for malignancy within 5 years of enrollment, with the exception of complete resection of basal cell carcinoma or squamous cell carcinoma of the skin, an in situ malignancy, or low-risk prostate cancer after curative therapy. * Contraindication to kidney transplantation or donation-active infection, comorbid medical conditions, etc