The purpose of this study is to understand the role of specific B cells in activating or repressing an anti-allograft immune response after kidney transplantation. In this study, blood will be collected from kidney transplant patients during different timepoints, prior to and after their transplant. Knowledge gained from study findings will be used to develop therapeutic strategies to prevent antibody-mediated rejection, which is a major cause of long-term graft loss in kidney transplant patients.

The purpose of this study is to understand the role of specific B cells in activating or repressing an anti-allograft immune responses after kidney transplantation. This study aims to address two major challenges in kidney transplantation: 1. to guide physicians when immunosuppressive drugs are weaned, and 2. to identify patients who are at risk or in the process of developing antibody-mediated rejection. In this study, blood will be collected from kidney transplant patients during different timepoints, prior to and after their transplant. Knowledge gained from study findings will be used to develop therapeutic strategies to prevent antibody-mediated rejection, which is a major cause of long-term graft loss in kidney transplant patients.

Inclusion Criteria:

• Ability to understand and willingness to sign the written informed consent form (ICF). For pediatric patients, a parent or legal guardian must sign ICF
• Either a Kidney or Liver transplant patient: 1) on the waitlist or 2) transplanted
• Healthy volunteer samples collected to use as the control group for statistical validity

Exclusion Criteria:

• Inability to make all of the required long-term post-transplant visits.
• Females who are pregnant or nursing a child
• Liver patients with hepatitis C virus

Pediatric and Adult patients who are on the waitlist for a kidney or liver, or are about to undergo kidney or liver transplantation.