Ervin Steve Woodle

Lupus nephritis (LN), a severe manifestation of systemic lupus erythematosus (SLE), is a heterogeneous disease driven by diverse immune and tissue cell types. We obtained 538,194 single-cell and 142,881 single-nuclear profiles from kidney biopsies of 155 patients with LN and 30 preimplantation transplant biopsy controls, along with 327,326 single-cell blood profiles. We characterized key stromal and immune cell types and cell states; moreover, we distinguished cell states that were tissue specific from those that were also present in the blood. We observed that LN pathological features were associated with particular cell states. For example, after controlling for the effects of chronic tissue damage, we observed that expansion of glomerular and scar-associated macrophage populations correlated with increasing inflammatory disease activity. Scar-associated macrophages appear to drive LN fibrosis and, in active disease, infiltrate the glomeruli more than other myeloid cells. These observations support that therapeutic targeting of myeloid populations may offer a strategy to prevent renal inflammation and ongoing kidney damage in LN.

Belatacept (BELA) pharmacokinetic (PK) studies informed dosing strategies used in phase 3 studies, where fixed mg/kg dosing compared a less intensive (LI) and more intensive (MI) regimen. The LI regimen was preferred due to a better risk/benefit profile. We compared PK parameters observed in the BELA Early Steroid Withdrawal Trial (BEST) with previous reports. BELA trough samples were analyzed using a validated quantitative enzyme‐linked immunoassay. Clearance (CL) was estimated with Bayesian estimation using a published BELA population PK model. Significantly higher CL was observed in subjects Trial Registration : ClinicalTrials.gov identifier: NCT 01729494

Lupus nephritis (LN) is a frequent manifestation of systemic lupus erythematosus, and fewer than half of patients achieve complete renal response with standard immunosuppressants. Identifying noninvasive, blood-based immune alterations associated with renal injury could aid therapeutic decisions. Here, we used mass cytometry immunophenotyping of peripheral blood mononuclear cells in 145 patients with biopsy-proven LN and 40 healthy controls to evaluate the heterogeneity of immune activation and identify correlates of renal parameters. Unbiased analysis identified 3 immunologically distinct groups of patients that were associated with different patterns of histopathology, renal cell infiltrates, urine proteomic profiles, and treatment response at 1 year. Patients with enriched circulating granzyme B ⁺ T cells showed more active disease and increased numbers of activated CD8 ⁺ T cells in the kidney, yet they had the highest likelihood of treatment response. A second group characterized by a high type I interferon signature had a lower likelihood of response to therapy, while a third group appeared immunologically inactive but with chronic renal injuries. The major immunologic axes of variation could be distilled down to 5 simple cytometric parameters that recapitulate several clinical associations, highlighting the potential for blood immunoprofiling to translate to clinically useful noninvasive metrics to assess immune-mediated disease in LN.

Background.: Belatacept, a selective T-cell costimulation blocker, was associated with improved survival and renal function but also with a risk of posttransplant lymphoproliferative disorder (PTLD) in adult kidney transplant recipients in phase 3 trials. This registry examined long-term safety in Epstein–Barr virus (EBV)–seropositive kidney transplant recipients treated with belatacept. Methods.: This US-based, prospective, voluntary, multicenter registry (Evaluating Nulojix Long-Term Safety in Transplant [ENLiST]) included adult EBV-seropositive kidney-only transplant recipients treated de novo (within 14 d of transplantation) with belatacept. Primary objectives were to estimate incidence rates of confirmed PTLD, central nervous system (CNS) PTLD, and progressive multifocal encephalopathy (PML). The minimum follow-up was 2 y. Results.: Of 985 enrolled transplant recipients, 933 EBV-seropositive patients received belatacept, with 523 (56.1%) receiving concomitant tacrolimus at transplant (for up to 12 mo). By study end, 3 cases of non-CNS PTLD (incidence rate, 0.08/100 person-years), 1 case of CNS PTLD (0.03/100 person-years), and no cases of PML had been reported. Two patients with non-CNS PTLD received concomitant belatacept and tacrolimus and 1 received belatacept and lymphocyte-depleting therapy. Incidence rates were comparable between patients who received concomitant belatacept and tacrolimus and those who did not receive tacrolimus (0.09/100 person-years and 0.07/100 person-years, respectively; P = 0.96). Two of 4 patients with PTLD died, and 2 were alive at the end of the study. Cumulatively, 131 graft losses or deaths were reported by study end. Conclusions.: Our results from the ENLiST registry, a large, prospective real-world study, showed that the incidence rates of PTLD and CNS PTLD in belatacept-treated EBV-seropositive transplant recipients were consistent with findings from previous phase 3 trials.

The proteasome inhibitor bortezomib (BTZ) is proposed to deplete activated B cells and plasma cells. However, a complete picture of the mechanisms underlying BTZ-induced apoptosis in B lineage cells remains to be established. In this study, using a direct in vitro approach, we show that deletion of the tumor suppressor and cell cycle regulator p53 rescues recently activated mouse B cells from BTZ-induced apoptosis. Furthermore, BTZ treatment elevated intracellular p53 levels, and p53 deletion constrained apoptosis, as recently stimulated cells first transitioned from the G1 to S phase of the cell cycle. Moreover, combined inhibition of the p53-associated cell cycle regulators and E3 ligases MDM2 and anaphase-promoting complex/cyclosome induced cell death in postdivision B cells. Our results reveal that efficient cell cycle progression of activated B cells requires proteasome-driven inhibition of p53. Consequently, BTZ-mediated interference of proteostasis unleashes a p53-dependent cell cycle–associated death mechanism in recently activated B cells.

Background: To date, the evidence for proteasome‐inhibitor (PI) based antibody mediated rejection (AMR) therapy has been with the first‐generation PI bortezomib. Results have demonstrated encouraging efficacy for early AMR with lesser efficacy for late AMR. Unfortunately, bortezomib is associated with dose‐limiting adverse effects in some patients. We report use of the second generation proteosome inhibitor carfilzomib for AMR treatment in two pediatric patients with a kidney transplant.Methods: The clinical data on two patients who experienced dose limiting toxicities from bortezomib were collected along with their short‐ and long‐term outcomes.Results: A two‐year‐old female with simultaneous AMR, multiple de novo DSAs (DR53 MFI 3900, DQ9 MFI 6600, DR15 2200, DR51 MFI 1900) and T‐cell mediated rejection (TCMR) completed three carfilzomib cycles and experienced stage 1 acute kidney injury after the first two cycles. At 1 year follow up, all DSAs resolved, and her kidney function returned to baseline without recurrence. A 17‐year‐old female also developed AMR with multiple de novo DSAs (DQ5 MFI 9900, DQ6 MFI 9800, DQA*01 MFI 9900). She completed two carfilzomib cycles, which were associated with acute kidney injury. She had resolution of rejection on biopsy and decreased but persistent DSAs on follow‐up.Conclusions: Carfilzomib treatment for bortezomib‐refractory rejection and/or bortezomib toxicity may provide DSA elimination or reduction, but also appears to be associated with nephrotoxicity. Clinical development of carfilzomib for AMR will require a better understanding of efficacy and development of approaches to mitigate nephrotoxicity.

Background and objectives: Immunosuppressive therapy in kidney transplantation is associated with numerous toxicities. CD28-mediated T-cell costimulation blockade using belatacept may reduce long-term nephrotoxicity, compared with calcineurin inhibitor–based immunosuppression. The efficacy and safety of simultaneous calcineurin inhibitor avoidance and rapid steroid withdrawal were tested in a randomized, prospective, multicenter study. Design, setting, participants, & measurements: This study reports the 2-year results of a randomized clinical trial of 316 recipients of a new kidney transplant. All kidney transplants were performed using rapid steroid withdrawal immunosuppression. Recipients were randomized in a 1:1:1 ratio to receive belatacept with alemtuzumab induction, belatacept with rabbit anti-thymocyte globulin (rATG) induction, or tacrolimus with rATG induction. The composite end point consisted of death, kidney allograft loss, or an eGFR of 2 at 2 years. Results: The composite end point was observed for 11 of 107 (10%) participants assigned to belatacept/alemtuzumab, 13 of 104 (13%) participants assigned to belatacept/rATG, and 21 of 105 (21%) participants assigned to tacrolimus/rATG (for belatacept/alemtuzumab versus tacrolimus/rATG, P=0.99; for belatacept/rATG versus tacrolimus/rATG, P=0.66). Patient and graft survival rates were similar between all groups. An eGFR of 2 was observed for nine of 107 (8%) participants assigned to belatacept/alemtuzuab, eight of 104 (8%) participants assigned to belatacept/rATG, and 20 of 105 (19%) participants assigned to tacrolimus/rATG (PP=0.006; for belatacept/rATG versus tacrolimus/rATG, P2 was significantly lower with belatacept compared with tacrolimus, but the incidence of biopsy sample–proven acute rejection significantly higher. Clinical Trial registry name and registration number: Belatacept Early Steroid Withdrawal Trial, NCT01729494