Mark D. Stegall

Risk factors for primary dysfunction after liver transplantation - A multivariate analysis

In a retrospective analysis on 323 orthotopic liver transplant procedures performed between July 1984 and October 1991 the incidence of two forms of primary dysfunction (PDF) of the liver: primary nonfunction (PNF), and initial poor function (IPF) were studied. The incidence of PDF was 22% (73/323) with 6% PNF (20/323) and 16% IPF (53/323), while 78% (250/323) had immediate function (IF). Occurrence of both IPF and PNF resulted in a higher graft failure rate (P < 0.001), retransplantation rate (P < 0.001), and patient mortality (P < 0.003) within the first three months after OLTx. Univariate analyses of donor and recipient factors and their influence on PDF demonstrated that longer donor hospitalization (> 3 days), older donor age (> 49 years), extended preservation times (> 18 hr), and fatty changes in the donor liver biopsy, as well as reduced-size livers, younger recipient age, and renal insufficiency prior to OLTx, significantly affected the incidence of IPF and PNF. Multivariate analysis of potential risk factors showed that reduced-size liver (P = 0.0001), fatty changes on donor liver biopsy (P = 0.001), older donor age (P = 0.009), retransplantation (P = 0.01), renal insufficiency (P = 0.02), and prolonged cold ischemia times (P = 0.02) were independently associated with a higher incidence of IPF and PNF. No statistical correlation was found between PDF and etiology of ESLD, nutritional status of the recipient, UNOS status, and Child-Pugh classification in this study. We conclude that PNF and IPF are both separate clinical entities that have a significant effect on outcome after OLTx. Routine donor liver biopsies are recommended to decrease the rate of IPF and PNF. The combination of risk factors shown to be significant for PDF should be avoided--and, if that is not possible, the only variable that can be controlled, the preservation time, should be kept as short as possible.

Identifying Specific Causes of Kidney Allograft Loss

The causes of kidney allograft loss remain unclear. Herein we investigated these causes in 1317 conventional kidney recipients. The cause of graft loss was determined by reviewing clinical and histologic information the latter available in 98% of cases. During 50.3 ± 32.6 months of follow‐up, 330 grafts were lost (25.0%), 138 (10.4%) due to death with function, 39 (2.9%) due to primary nonfunction and 153 (11.6%) due to graft failure censored for death. The latter group was subdivided by cause into: glomerular diseases (n = 56, 36.6%); fibrosis/atrophy (n = 47, 30.7%); medical/surgical conditions (n = 25, 16.3%); acute rejection (n = 18, 11.8%); and unclassifiable (n = 7, 4.6%). Glomerular pathologies leading to failure included recurrent disease (n = 23), transplant glomerulopathy (n = 23) and presumed nonrecurrent disease (n = 10). In cases with fibrosis/atrophy a specific cause(s) was identified in 81% and it was rarely attributable to calcineurin inhibitor (CNI) toxicity alone (n = 1, 0.7%). Contrary to current concepts, most cases of kidney graft loss have an identifiable cause that is not idiopathic fibrosis/atrophy or CNI toxicity. Glomerular pathologies cause the largest proportion of graft loss and alloinmunity remains the most common mechanism leading to failure. This study identifies targets for investigation and intervention that may result in improved kidney transplantation outcomes.

Terminal complement inhibition decreases antibody-mediated rejection in sensitized renal transplant recipients.

Sensitized renal transplant recipients with high levels of donor‐specific alloantibody (DSA) commonly develop antibody‐mediated rejection (AMR), which may cause acute graft loss or shorten allograft survival. We examined the efficacy of terminal complement inhibition with the humanized anti‐C5 antibody, eculizumab, in the prevention AMR in renal transplant recipients with a positive crossmatch against their living donor. The incidence of biopsy‐proven AMR in the first 3 months posttransplant in 26 highly sensitized recipients of living donor renal transplants who received eculizumab posttransplant was compared to a historical control group of 51 sensitized patients treated with a similar plasma exchange (PE)‐based protocol without eculizumab. The incidence of AMR was 7.7% (2/26) in the eculizumab group compared to 41.2% (21/51) in the control group (p = 0.0031). Eculizumab also decreased AMR in patients who developed high levels of DSA early after transplantation that caused proximal complement activation. With eculizumab, AMR episodes were easily treated with PE reducing the need for splenectomy. On 1‐year protocol biopsy, transplant glomerulopathy was found to be present in 6.7% (1/15) eculizumab‐treated recipients and in 35.7% (15/42) of control patients (p = 0.044). Inhibition of terminal complement activation with eculizumab decreases the incidence of early AMR in sensitized renal transplant recipients (ClincalTrials.gov number NCT006707).

A Comparison of Plasmapheresis Versus High-Dose IVIG Desensitization in Renal Allograft Recipients with High Levels of Donor Specific Alloantibody

Several protocols allow for the successful transplantation of sensitized renal allograft recipients, yet no one best method has emerged. The aim of the current study was to compare the efficacy of high‐dose IVIG with two different plasmapheresis (PP)‐based regimens in kidney transplant recipients with high levels of donor specific alloantibody (DSA) defined as a positive T‐cell cytotoxicity crossmatch. With the primary goal of achieving a negative crossmatch, we employed three protocols sequentially between April 2000 and May 2005: (i) PP, low‐dose IVIG, anti‐CD20 antibody (n = 32); (ii) high‐dose IVIG (n = 13); and (iii) PP, low‐dose IVIG, anti‐CD20 antibody and pre‐transplant Thymoglobulin combined with post‐transplant DSA monitoring (n = 16). IVIG decreased DSA activity in all treated patient, yet only 38% (5/13) achieved a negative crossmatch. In contrast, a negative crossmatch was achieved in 84% in PP group and 88% in the PP/monitoring group (p < 0.01 vs. IVIG). Even with a negative crossmatch, the rejection rates were 80% (IVIG), 37% (PP) and 29% (PP/monitoring), respectively, (p < 0.05 IVIG vs. PP). We conclude that multiple PP treatments leads to more reproducible desensitization and lower humoral rejection rates than a single high‐dose of IVIG, but that no regimen was completely effective in preventing humoral rejection.

Complete avoidance of calcineurin inhibitors in renal transplantation : A randomized trial comparing sirolimus and tacrolimus

Calcineurin inhibitors have decreased acute rejection and improved early renal allograft survival, but their use has been implicated in the development of chronic nephrotoxicity. We performed a prospective, randomized trial in kidney transplantation comparing sirolimus‐MMF‐prednisone to tacrolimus‐MMF‐prednisone. Eighty‐one patients in the sirolimus group and 84 patients in the tacrolimus group were enrolled (mean follow‐up = 33 months; range 13–47 months). At 1 year, patient survival was similar in the groups (98% with sirolimus, 96% with tacrolimus; p = 0.42) as was graft survival (94% sirolimus vs. 92% tacrolimus, p = 0.95). The incidence of clinical acute rejection was 10% in the tacrolimus group and 13% in the sirolimus group (p = 0.58). There was no difference in mean GFR measured by iothalamate clearance between the tacrolimus and sirolimus groups at 1 year (61 ± 19 mL/min vs. 63 ± 18 mL/min, p = 0.57) or 2 years (61 ± 17 mL/min vs. 61 ± 19 mL/min, p = 0.84). At 1 year, chronicity using the Banff schema showed no difference in interstitial, tubular or glomerular changes, but fewer chronic vascular changes in the sirolimus group. This study shows that a CNI‐free regimen using sirolimus‐MMF‐prednisone produces similar acute rejection rates, graft survival and renal function 1–2 years after transplantation compared to tacrolimus‐MMF‐prednisone.

Transplant Glomerulopathy: Subclinical Incidence and Association with Alloantibody

Transplant glomerulopathy (TG) usually has been described as part of a constellation of late chronic histologic abnormalities associated with proteinuria and declining function. The current study used both protocol and clinically‐indicated biopsies to investigate clinical and subclinical TG, their prognosis and possible association with alloantibody. We retrospectively studied 582 renal transplants with a negative pre‐transplant T‐cell complement dependent cytotoxicity crossmatch. TG was diagnosed in 55 patients, 27 (49%) based on protocol biopsy in well‐functioning grafts. The cumulative incidence of TG increased over time to 20% at 5 years. The prognosis of subclinical TG was equally as poor as TG diagnosed with graft dysfunction, with progressive worsening of histopathologic changes and function. Although TG was associated with both acute and chronic histologic abnormalities, 14.5% of TG biopsies showed no interstitial fibrosis or tubular atrophy, while 58% (7/12) of biopsies with severe TG showed only minimal abnormalities. TG was associated with acute rejection, pretransplant hepatitis C antibody positivity and anti‐HLA antibodies (especially anti‐Class II), with the risk increasing if the antibodies were donor specific. We suggest that subclinical TG is an under‐recognized cause of antibody‐mediated, chronic renal allograft injury which may be mechanistically distinct from other causes of nephropathy.

Randomized Trial Of Tacrolimus (prograf) In Combination With Azathioprine Or Mychophenolate Mofetil Versus Cyclosporine (neoral) With Mycophenolate Mofetil After Cadaveric Kidney Transplantation1, 2

BACKGROUND Our clinical trial was designed to investigate the optimal combination of immunosuppressants for renal transplantation. METHODS A randomized three-arm, parallel group, open label, prospective study was performed at 15 North American centers to compare three immunosuppressive regimens: tacrolimus + azathioprine (AZA) versus cyclosporine (Neoral) + mycophenolate mofetil (MMF) versus tacrolimus + MMF. All patients were first cadaveric kidney transplants receiving the same maintenance corticosteroid regimen. Only patients with delayed graft function (32%) received antilymphocyte induction. A total of 223 patients were randomized, transplanted, and followed for 1 year. RESULTS There were no significant differences in baseline demography between the three treatment groups. At 1 year the results are as follows: acute rejection 17% (95% confidence interval 9%, 26%) in tacrolimus + AZA; 20% (confidence interval 11%, 29%) in cyclosporine + MMF; and 15% (confidence interval 7%, 24%) in tacrolimus + MMF. The incidence of steroid resistant rejection requiring antilymphocyte therapy was 12% in the tacrolimus + AZA group, 11% in the cyclosporine + MMF group, and 4% in the tacrolimus + MMF group. There were no significant differences in overall patient or graft survival. Tacrolimus-treated patients had a lower incidence of hyperlipidemia through 6 months posttransplant. The incidence of posttransplant diabetes mellitus requiring insulin was 14% in the tacrolimus + AZA group, 7% in the cyclosporine + MMF and 7% in the tacrolimus + MMF groups. CONCLUSIONS All regimens yielded similar acute rejection rates and graft survival, but the tacrolimus + MMF regimen was associated with the lowest rate of steroid resistant rejection requiring antilymphocyte therapy.

Predicting subsequent decline in kidney allograft function from early surveillance biopsies

Identifying factors that are predictive of allograft loss might be an important step toward prolonging kidney allograft survival. In this study we sought to determine the association between histologic changes on 1‐year surveillance biopsies, changes in graft function and survival. This analysis included 292 adults, recipients of kidneys from living donors (69%) or deceased donors (31%), transplanted between 1998 and 2001 and followed up for 46 ± 14 months. The primary end point was death‐censored graft loss or a >50% reduction in GFR beyond 1 year. One‐year biopsies were classified as: (i) Normal (N = 87, 30%), (ii) inflammation (N = 6, 2%), (iii) fibrosis (N = 131, 45%), (iv) fibrosis and inflammation (N = 53, 18%) and (v) transplant glomerulopathy (N = 15, 5%). By multivariate Cox analysis, survival related to biopsy classification (HR = 4.2, p = 0.001), graft function (HR = 0.97, p = 0.001) and HLA mismatches (HR = 1.003, p = 0.004). Using normal histology as a reference, fibrosis and inflammation (HR = 8.5, p < 0.0001) and glomerulopathy (HR = 10, p < 0.0001) related to poorer survival but mild fibrosis alone did not. Importantly, the degree of inflammation associated with fibrosis generally did not qualify for the diagnosis of borderline rejection. In conclusion, inflammation and glomerulopathy 1 year post‐transplant predict loss of graft function and graft failure independently of function and other variables.

Wound-healing complications after kidney transplantation: a prospective, randomized comparison of sirolimus and tacrolimus.

Background. Sirolimus has been associated with an increased risk of wound-healing complications in several retrospective analyses. The authors compared the rates of wound-healing complications in renal allograft recipients in a prospective, randomized trial of sirolimus-mycophenolate mofetil-prednisone versus tacrolimus-mycophenolate mofetil-prednisone. Methods. All patients received antithymocyte globulin induction. In the first phase of the study, patients (n=77) were included regardless of body mass index (BMI). In the second phase (n=46 patients), the authors excluded patients with a BMI greater than 32 kg/m2, and the target trough sirolimus level was lowered to 10 to 15 ng/mL (previously 15–20 ng/mL). Multivariate logistic regression analyses were performed to identify predictors of wound complications. Results. Fifty-nine patients received tacrolimus and 64 received sirolimus and were included in subsequent analyses. The incidence of complications was 8% (5 of 59) in the tacrolimus group and 47% (30 of 64) in the sirolimus group (P <0.0001). Rates of perigraft fluid collections, superficial wound infections, and incisional herniae were significantly higher in the sirolimus group. Multivariate logistic regression showed only sirolimus (P =0.0001) and BMI (P =0.0021) to independently correlate with complications. In the first phase of the study, the wound complication rate in the sirolimus group was 55% (21 of 38 patients). After excluding obese recipients and decreasing the target sirolimus level, the wound complication rate in the sirolimus group was 35% (9 of 26 patients; P =0.1040). Conclusions. The use of sirolimus-based immunosuppressive regimens leads to a higher incidence of wound-healing complications and will require new approaches to patient selection and management to decrease their incidence.

Proteasome Inhibition Causes Apoptosis of Normal Human Plasma Cells Preventing Alloantibody Production

Antibody production by normal plasma cells (PCs) against human leukocyte antigens (HLA) can be a major barrier to successful transplantation. We tested four reagents with possible activity against PCs (rituximab, polyclonal rabbit antithymocyte globulin (rATG), intravenous immunoglobulin (IVIG) and the proteasome inhibitor, bortezomib) to determine their ability to cause apoptosis of human bone marrow‐derived PCs and subsequently block IgG secretion in vitro. IVIG, rituximab and rATG all failed to cause apoptosis of PCs and neither rituximab nor rATG blocked antibody production. In contrast, bortezomib treatment led to PC apoptosis and thereby blocked anti‐HLA and antitetanus IgG secretion in vitro. Two patients treated with bortezomib for humoral rejection after allogeneic kidney transplantation demonstrated a transient decrease in bone marrow PCs in vivo and persistent alterations in alloantibody specificities. Total IgG levels were unchanged. We conclude that proteasome activity is important for PC longevity and its inhibition may lead to new techniques of controlling antibody production in vivo.