Stephan Busque

Tolerance and Chimerism after Renal and Hematopoietic-Cell Transplantation

We describe a recipient of combined kidney and hematopoietic-cell transplants from an HLA-matched donor. A post-transplantation conditioning regimen of total lymphoid irradiation and antithymocyte globulin allowed engraftment of the donors hematopoietic cells. The patient had persistent mixed chimerism, and the function of the kidney allograft has been normal for more than 28 months since discontinuation of all immunosuppressive drugs. Adverse events requiring hospitalization were limited to a 2-day episode of fever with neutropenia. The patient has had neither rejection episodes nor clinical manifestations of graft-versus-host disease.

C1q-fixing human leukocyte antigen antibodies are specific for predicting transplant glomerulopathy and late graft failure after kidney transplantation.

Background. Human leukocyte antigen (HLA) antibodies, especially those that fix complement, are associated with antibody-mediated rejection and graft failure. The C1q assay on single antigen beads detects a subset of HLA antibodies that can fix complement and precede C4d deposition. The aim of this study was to determine whether C1q-fixing antibodies distinguish de novo donor-specific antibodies (DSA) that are clinically relevant and harmful. Methods. We retrospectively studied 31 of 274 kidney transplant recipients who had pretransplant and concurrent biopsy and serum specimens, 13 with C4d-positive and 18 with C4d-negative staining. We measured IgG and C1q DSA pretransplant and at the time of biopsy using single antigen bead assays. We identified 13 recipients who developed de novo DSA by IgG or C1q and examined associations with C4d deposition, transplant glomerulopathy, and graft failure. Results. Testing for DSA by IgG is more sensitive for C4d deposition (IgG: 100%, 95% confidence interval [CI] 0.60–1; C1q: 75%, 95% CI 0.36–0.96). Testing for DSA by C1q is more specific for transplant glomerulopathy (C1q: 81%, 95% CI 0.57–0.94; IgG: 67%, 95% CI 0.43–0.85) and graft loss (C1q: 79%, 95% CI 0.54–0.93; IgG: 63%, 95% CI 0.39–0.83). Absence of de novo DSA by IgG and C1q has a high negative predictive value for the absence of C4d deposition (IgG: 100%, 95% CI 0.73–1; C1q: 88%, 95% CI 0.62–0.98), transplant glomerulopathy (IgG: 100%, 95% CI 0.73–1; C1q: 100%, 95% CI 0.77–1), and graft failure (IgG: 86%, 95% CI 0.56–0.97; C1q: 88%, 95% CI 0.62–0.98). Conclusion. Monitoring patients with the C1q assay, which detects antibodies that fix complement, offers a minimally invasive means of identifying patients at risk for transplant glomerulopathy and graft loss.

Tolerance and Withdrawal of Immunosuppressive Drugs in Patients Given Kidney and Hematopoietic Cell Transplants

Sixteen patients conditioned with total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) were given kidney transplants and an injection of CD34+ hematopoietic progenitor cells and T cells from HLA‐matched donors in a tolerance induction protocol. Blood cell monitoring included changes in chimerism, balance of T‐cell subsets and responses to donor alloantigens. Fifteen patients developed multilineage chimerism without graft‐versus‐host disease (GVHD), and eight with chimerism for at least 6 months were withdrawn from antirejection medications for 1–3 years (mean, 28 months) without subsequent rejection episodes. Four chimeric patients have just completed or are in the midst of drug withdrawal, and four patients were not withdrawn due to return of underlying disease or rejection episodes. Blood cells from all patients showed early high ratios of CD4+CD25+ regulatory T cells and NKT cells versus conventional naive CD4+ T cells, and those off drugs showed specific unresponsiveness to donor alloantigens. In conclusion, TLI and ATG promoted the development of persistent chimerism and tolerance in a cohort of patients given kidney transplants and hematopoietic donor cell infusions. All 16 patients had excellent graft function at the last observation point with or without maintenance drugs.

Lack of Benefit of Early Protocol Biopsies in Renal Transplant Patients Receiving TAC and MMF: A Randomized Study

We conducted a randomized, multicenter study to determine whether treatment of subclinical rejection with increased corticosteroids resulted in beneficial outcomes in renal transplant patients receiving tacrolimus (TAC), mycophenolate mofetil (MMF) and prednisone. One hundred and twenty‐one patients were randomized to biopsies at 0,1,2,3 and 6 months (Biopsy arm), and 119 to biopsies at 0 and 6 months only (Control arm). The primary endpoint of the study was the prevalence of the sum of the interstitial and tubular scores (ci + ct)> 2 (Banff) at 6 months. Secondary endpoints included clinical and subclinical rejection and renal function. At 6 months, 34.8% of the Biopsy and 20.5% of the Control arm patients had a ci + ct score ≥ 2 (p = 0.07). Between months 0 and 6, clinical rejection episodes were 12 in 10 Biopsy arm patients and 8 in 8 Control arm patients (p = 0.44). Overall prevalence of subclinical rejection in the Biopsy arm was 4.6%. Creatinine clearance at 6 months was 72.9 ± 21.7 in the Biopsy and 68.90 mL/min ± 18.35 mL/min in the Control arm patients (p = 0.18). In conclusion, we found no benefit to the procurement of early protocol biopsies in renal transplant patients receiving TAC, MMF and prednisone, at least in the short term. This is likely due to their low prevalence of subclinical rejection.

Calcineurin‐Inhibitor‐Free Immunosuppression Based on the JAK Inhibitor CP‐690,550: A Pilot Study in De Novo Kidney Allograft Recipients

This randomized, pilot study compared the Janus kinase inhibitor CP‐690,550 (15 mg BID [CP15] and 30 mg BID [CP30], n = 20 each) with tacrolimus (n = 21) in de novo kidney allograft recipients. Patients received an IL‐2 receptor antagonist, concomitant mycophenolate mofetil (MMF) and corticosteroids. CP‐690,550 doses were reduced after 6 months. Due to a high incidence of BK virus nephropathy (BKN) in CP30, MMF was discontinued in this group. The 6‐month biopsy‐proven acute rejection rates were 1 of 20, 4 of 20 and 1 of 21 for CP15, CP30 and tacrolimus groups, respectively. BKN developed in 4 of 20 patients in CP30 group. The 6‐month rates of cytomegalovirus disease were 2 of 20, 4 of 20 and none of 21 for CP15, CP30 and tacrolimus groups, respectively. Estimated glomerular filtration rate was >70 mL/min at 6 and 12 months (all groups). NK cells were reduced by ≤77% in CP‐690,550‐treated patients. In the CP‐690,550 arms, there were modest lipid elevations and a trend toward more frequent anemia and neutropenia during the first 6 months. These data suggest that coadministration of CP‐690,550 30 mg BID with MMF is associated with overimmunosuppression. At 15 mg BID, the efficacy/safety profile was comparable to the tacrolimus control group, excepting a higher rate of viral infection. Further dose‐ranging evaluation of CP‐690,550 is warranted.

Randomized Phase 2b Trial of Tofacitinib (CP‐690,550) in De Novo Kidney Transplant Patients: Efficacy, Renal Function and Safety at 1 Year

In this Phase 2b study, 331 low‐to‐moderate risk de novo kidney transplant patients (approximately 60% deceased donors) were randomized to a more intensive (MI) or less intensive (LI) regimen of tofacitinib (CP‐690, 550), an oral Janus kinase inhibitor or cyclosporine (CsA). All patients received basiliximab induction, mycophenolic acid and corticosteroids. Primary endpoints were: incidence of biopsy‐proven acute rejection (BPAR) with a serum creatinine increase of ≥0.3 mg/dL and ≥20% (clinical BPAR) at Month 6 and measured GFR at Month 12. Similar 6‐month incidences of clinical BPAR (11%, 7% and 9%) were observed for MI, LI and CsA. Measured GFRs were higher (p < 0.01) at Month 12 for MI and LI versus CsA (65 mL/min, 65 mL/min vs. 54 mL/min). Fewer (p < 0.05) patients in MI or LI developed chronic allograft nephropathy at Month 12 compared with CsA (25%, 24% vs. 48%). Serious infections developed in 45%, 37% and 25% of patients in MI, LI and CsA, respectively. Anemia, neutropenia and posttransplant lymphoproliferative disorder occurred more frequently in MI and LI compared with CsA. Tofacitinib was equivalent to CsA in preventing acute rejection, was associated with improved renal function and less chronic allograft histological injury, but had side‐effects at the doses evaluated.

Tacrolimus (FK506) and sirolimus (rapamycin) in combination are not antagonistic but produce extended graft survival in cardiac transplantation in the rat

Combined use of tacrolimus (FK506) with sirolimus (rapamycin [RAPA]) was examined in a model of vascularized heart allograft in the rat. For prevention of acute rejection, three different combinations of low doses of FK506 and RAPA from day 1 up to day 14 after transplantation produced significantly longer cardiac allograft survival than each agent alone (P<0.05). Identical results were observed in a model of reversal of ongoing acute rejection, where two combinations of low doses of FK506 and RAPA from day 4 up to day 18 after surgery also demonstrated significantly longer graft survival than each immunosuppressant alone (P<0.05). All the low-dose-treated groups in these two models presented significantly longer heart graft survival than naive controls (P<0.05), confirming that both agents are potent immunosuppressants in the models chosen. These results also indicate that, in contrast with in vitro studies, the combined use of FK506 and RAPA in vivo did not produce antagonism, but rather had synergistic effect in prolonging the allograft survival as compared with each agent alone. It appears likely that the abundance of FKBP-12 available for binding in vivo prevents inhibitive competition of the two agents for their receptor.

Chimerism, graft survival, and withdrawal of immunosuppressive drugs in HLA matched and mismatched patients after living donor kidney and hematopoietic cell transplantation.

Thirty‐eight HLA matched and mismatched patients given combined living donor kidney and enriched CD34+ hematopoietic cell transplants were enrolled in tolerance protocols using posttransplant conditioning with total lymphoid irradiation and anti‐thymocyte globulin. Persistent chimerism for at least 6 months was associated with successful complete withdrawal of immunosuppressive drugs in 16 of 22 matched patients without rejection episodes or kidney disease recurrence with up to 5 years follow up thereafter. One patient is in the midst of withdrawal and five are on maintenance drugs. Persistent mixed chimerism was achieved in some haplotype matched patients for at least 12 months by increasing the dose of T cells and CD34+ cells infused as compared to matched recipients in a dose escalation study. Success of drug withdrawal in chimeric mismatched patients remains to be determined. None of the 38 patients had kidney graft loss or graft versus host disease with up to 14 years of observation. In conclusion, complete immunosuppressive drug withdrawal could be achieved thus far with the tolerance induction regimen in HLA matched patients with uniform long‐term graft survival in all patients.

Experience with the piggyback technique without caval occlusion in adult orthotopic liver transplantation

BACKGROUND To assess the feasibility and outcome of a piggyback technique without caval occlusion or veno-venous bypass (VB), we retrospectively reviewed 131 consecutive adult orthotopic liver transplantation (OLT) performed in 129 patients between May 1993 and February 1995. Six were second transplants, and six were combined liver-kidney transplants. The piggyback technique was attempted in all cases. METHODS We were able to perform the piggyback technique in 98 OLTs (75%). The remaining 33 OLTs (25%) were converted to the standard technique; of these, 20 (15%) required VB. The reasons for conversion to the standard technique were: anatomical (22 transplants), severe portal hypertension requiring VB (8 transplants), tumor (1 transplant), and other reasons (2 transplants). Six retransplantations were performed (four piggyback, two standard). RESULTS There was no significant difference in age, United Network for Organ Sharing status, Childs classification, and diagnosis between the patients in whom piggyback was possible or not. The actuarial patient and graft survival at 1 year were similar between the piggyback group and the group of patients converted to standard technique (87/85% vs. 86/86%, respectively). No death was related to either technique. With piggyback, the average operative time was 8.6+/-1.9 hr, median amount of blood transfused intraoperatively was 2 U (33% did not require transfusion), and median intensive care unit and hospital stays were 3 and 11 days, respectively. With the piggyback technique, the mean preoperative and maximum postoperative serum creatinine levels were 1.4+/-1.0 and 1.8+/-1.5 mg/dl. CONCLUSION The piggyback technique without caval occlusion is possible in the majority of patients. It is safe and has reduced the use of VB to 15% of our adult OLTs. The piggyback technique avoids retrocaval dissection, facilitates retransplantation, and is associated with a short anhepatic phase, low blood product usage, and short intensive care unit stay.

Effects of aging on glomerular function and number in living kidney donors

To elucidate the pathophysiologic changes in the kidney due to aging, we used physiological, morphometric, and imaging techniques to quantify GFR and its determinants in a group of 24 older (≥ 55 years) compared to 33 younger (≤ 45 years) living donors. Mathematical modeling was used to estimate the glomerular filtration coefficients for the whole kidney (K(f)) and for single nephrons (SNK(f)), as well as the number of filtering glomeruli (N(FG)). Compared to younger donors, older donors had a modest (15%) but significant depression of pre-donation GFR. Mean whole-kidney K(f), renocortical volume, and derived N(FG) were also significantly decreased in older donors. In contrast, glomerular structure and SNK(f) were not different in older and younger donors. Derived N(FG) in the bottom quartile of older donors was less than 27% of median-derived N(FG) in the two kidneys of younger donors. Nevertheless, the remaining kidney of older donors exhibited adaptive hyperfiltration and renocortical hypertrophy post-donation, comparable to that of younger donors. Thus, our study found the decline of GFR in older donors is due to a reduction in K(f) attributable to glomerulopenia. We recommend careful monitoring for and control of post-donation comorbidities that could exacerbate glomerular loss.