Jagdeep S. Obhrai

Cardiac evaluation prior to kidney transplantation

Kidney transplantation is the treatment of choice for most patients with stage 5 chronic kidney disease and end‐stage renal disease (ESRD), offering improved quality of life and overall survival rates. However, the limited supply of available organs makes this a scarce resource. Cardiovascular complications continue to be the leading cause of mortality in the kidney transplant population, accounting for over 30% of deaths with a functioning allograft. Thus, preoperative cardiac risk assessment is critical to optimize patient selection and outcomes. Currently there is no consensus for cardiovascular evaluation in the chronic kidney disease and ESRD population prior to kidney transplantation; the recommendations of the American Society of Nephrology and American Society of Transplantation differ from those of the American Heart Association and the American College of Cardiology. Previously developed risk scores have also been used to risk stratify this population. In this review, we discuss two cases that illustrate the difficulties of interpreting the prognostic value of current testing strategies. We also discuss the importance of different tests for cardiovascular evaluation as well as previous nonkidney transplant specific risk scores used in the pre‐kidney transplant population.

Type I Interferons Are Not Critical for Skin Allograft Rejection or the Generation of Donor‐Specific CD8+ Memory T Cells

Type I interferons (IFN‐I) link innate to adaptive immunity in microbial infection, autoimmune disease and tumor immunity. It is not known whether IFN‐I have an equally central role in alloimmunity. Here we tested this possibility by studying skin allograft survival and donor‐specific CD8+ T‐cell responses in mice that lack the IFN‐I receptor (IFN‐IR−/−). We found that IFN‐IR−/− mice reject fully allogeneic wild‐type skin grafts at the same rate as wild‐type recipients. Similarly, allograft rejection was not delayed if IFN‐IR−/− male skin was transplanted to syngeneic IFN‐IR−/− female mice. Quantitation of the male (H‐Y)‐specific CD8+ T‐cell response in these mice revealed normal generation of donor‐specific CD8+ effector T cells but fourfold reduction in CD8+ memory T cells. Memory CD8+ T cells generated in the absence of IFN‐IR had normal phenotype and recall function, assessed by ex vivo cytokine production and the ability of IFN‐IR−/− mice to mount second set rejection. Finally, these memory T cells were maintained at a constant number despite their inability to respond to IFN‐1. Our findings indicate that IFN‐I cytokines are not critical for acute allograft rejection or for the expansion and differentiation of donor‐specific CD8+ T cells into long‐lived, functional memory T cells.

Fellows’ Forum: Cardiac Evaluation Prior to Kidney Transplantation

Kidney transplantation is the treatment of choice for most patients with stage 5 chronic kidney disease and end‐stage renal disease (ESRD), offering improved quality of life and overall survival rates. However, the limited supply of available organs makes this a scarce resource. Cardiovascular complications continue to be the leading cause of mortality in the kidney transplant population, accounting for over 30% of deaths with a functioning allograft. Thus, preoperative cardiac risk assessment is critical to optimize patient selection and outcomes. Currently there is no consensus for cardiovascular evaluation in the chronic kidney disease and ESRD population prior to kidney transplantation; the recommendations of the American Society of Nephrology and American Society of Transplantation differ from those of the American Heart Association and the American College of Cardiology. Previously developed risk scores have also been used to risk stratify this population. In this review, we discuss two cases that illustrate the difficulties of interpreting the prognostic value of current testing strategies. We also discuss the importance of different tests for cardiovascular evaluation as well as previous nonkidney transplant specific risk scores used in the pre‐kidney transplant population.

Inflammation Causes Resistance to Anti-CD20-Mediated B Cell Depletion.

B cells play a central role in antibody‐mediated rejection and certain autoimmune diseases. However, B cell–targeted therapy such as anti‐CD20 B cell–depleting antibody (aCD20) has yielded mixed results in improving outcomes. In this study, we investigated whether an accelerated B cell reconstitution leading to aCD20 depletion resistance could account for these discrepancies. Using a transplantation model, we found that antigen‐independent inflammation, likely through toll‐like receptor (TLR) signaling, was sufficient to mitigate B cell depletion. Secondary lymphoid organs had a quicker recovery of B cells when compared to peripheral blood. Inflammation altered the pharmacokinetics (PK) and pharmacodynamics (PD) of aCD20 therapy by shortening drug half‐life and accelerating the reconstitution of the peripheral B cell pool by bone marrow–derived B cell precursors. IVIG (intravenous immunoglobulin) coadministration also shortened aCD20 drug half‐life and led to accelerated B cell recovery. Repeated aCD20 dosing restored B cell depletion and delayed allograft rejection, especially B cell–dependent, antibody‐independent allograft rejection. These data demonstrate the importance of further clinical studies of the PK/PD of monoclonal antibody treatment in inflammatory conditions. The data also highlight the disconnect between B cell depletion on peripheral blood compared to secondary lymphoid organs, the deleterious effect of IVIG when given with aCD20 and the relevance of redosing of aCD20 for effective B cell depletion in alloimmunity.

Blocking an Immune Inhibitor: Small Step or Giant Leap?

Cancer patients with an array of ligand-positive tumors can be treated safely with an antibody that blocks an inhibitory immune receptor.

A Tinier Target for B Cell Therapy in Multiple Sclerosis

Anti–IL-6 therapy may be an improved option for treatment of multiple sclerosis.

Cardiac Evaluation Prior to Kidney Transplantation: CARDIAC EVALUATION PRE-KIDNEY TRANSPLANT

Kidney transplantation is the treatment of choice for most patients with stage 5 chronic kidney disease and end‐stage renal disease (ESRD), offering improved quality of life and overall survival rates. However, the limited supply of available organs makes this a scarce resource. Cardiovascular complications continue to be the leading cause of mortality in the kidney transplant population, accounting for over 30% of deaths with a functioning allograft. Thus, preoperative cardiac risk assessment is critical to optimize patient selection and outcomes. Currently there is no consensus for cardiovascular evaluation in the chronic kidney disease and ESRD population prior to kidney transplantation; the recommendations of the American Society of Nephrology and American Society of Transplantation differ from those of the American Heart Association and the American College of Cardiology. Previously developed risk scores have also been used to risk stratify this population. In this review, we discuss two cases that illustrate the difficulties of interpreting the prognostic value of current testing strategies. We also discuss the importance of different tests for cardiovascular evaluation as well as previous nonkidney transplant specific risk scores used in the pre‐kidney transplant population.