Proteasome inhibitor-based therapy for antibody-mediated rejection

The development of donor-specific anti-human leukocyte antigen antibodies (DSAs) following renal transplantation significantly reduces long-term renal graft function and survival. The traditional therapies for antibody-mediated rejection (AMR) have provided inconsistent results and transient effects that may be due to a failure to deplete mature antibody-producing plasma cells. Proteasome inhibition (PI) is a novel AMR therapy that deletes plasma cells. Initial reports of PI-based AMR treatment in refractory rejection demonstrated the ability of bortezomib to deplete plasma cells producing DSA, reduce DSA levels, provide histological improvement or resolution, and improve renal allograft function. These results have subsequently been confirmed in a multicenter collaborative study. PI has also been shown to provide effective primary AMR therapy in case reports. Recent studies have demonstrated that PI therapy results in differential responses in early and late post-transplant AMR. Additional randomized studies are evaluating the role of PI in transplant induction, acute AMR, and chronic rejection in renal transplantation. An important theoretical advantage of PI-based regimens is derived from several potential strategies for achievement of synergy

The immune cell landscape in kidneys of patients with lupus nephritis.

Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies

Primum Non Nocere: Avoiding Harm to Vulnerable Wait List Candidates in an Indirect Kidney Exchange

Background: One proposal to increase kidney transplantation is to exchange kidneys between pairs of ABO-incompatible (or crossmatch -incompatible) living donors and their recipients. One variation that has greater potential exchanges living donor kidneys for cadaveric donor kidneys (indirect exchanges). A primary concern with indirect exchanges is the potential to disadvantage blood group O wait list candidates. Using wait list modeling, we examine whether this proposal would disadvantage cadaveric kidney blood group O wait list candidates, and present an approach for minimizing these negative effects. Methods: A probability model estimated the total number and blood type frequencies of donor-recipient pairs that would participate in indirect exchanges. A supply-to-demand model for the cadaveric kidney wait list estimated the mean wait time under different allocation policies and donor selection mechanisms for candidates on the wait list classified according to the candidates' race and blood type. Results: Indirect exchanges will reduce the mean wait time for cadaveric kidney wait list candidates. The mean wait time of blood group O cadaveric kidney wait list candidates increases when the participating living donors self-select and when kidney allocation is determined by efficiency. This is neutralized when the transplant team preferentially selects blood group O living donors and cadaveric kidney allocation is determined by need. Conclusion: Indirect exchange programs will significantly shorten the wait times for cadaveric kidney wait list candidates. The wait times of blood group O candidates will not be affected adversely if blood group O living donors are selected preferentially and if allocation is based on need.

Establishment of a nationalized, multiregional Paired Donation Network.

Over the past few years, significant progress has been made in the science and development of paired donation. With increasing awareness of paired donation and ready availability of the tools necessary to establish new consortia, paired donation can be made available to transplant programs and patients with increasing alacrity. Increasing registration of recipients and their donors for paired donation will lead to larger pools for matching and to transplantation of increasing numbers of patients via paired donation. As paired donation becomes common practice throughout the US and the international transplant community, its role in facilitating transplantation of sensitized patients will be better defined. Presently, paired donation remains an attractive alternative to desensitization and wait list paired donation for a majority of patients with preexisting humoral immunity to their donors