Diagnosis and management of antibody-mediated rejection: current status and novel approaches

Advances in multimodal immunotherapy have significantly reduced acute rejection rates and substantially improved 1-year graft survival following renal transplantation. However, long-term (10-year) survival rates have stagnated over the past decade. Recent studies indicate that antibody-mediated rejection (ABMR) is among the most important barriers to improving long-term outcomes. Improved understanding of the roles of acute and chronic ABMR has evolved in recent years following major progress in the technical ability to detect and quantify recipient anti-HLA antibody production. Additionally, new knowledge of the immunobiology of B cells and plasma cells that pertains to allograft rejection and tolerance has emerged. Still, questions regarding the classification of ABMR, the precision of diagnostic approaches, and the efficacy of various strategies for managing affected patients abound. This review article provides an overview of current thinking and research surrounding the pathophysiology and diagnosis of ABMR, ABMR-related outcomes, ABMR prevention and treatment, as well as possible future directions in treatment.

Solid-organ transplantation in older adults: current status and future research

An increasing number of patients older than 65 years are referred for and have access to organ transplantation, and an increasing number of older adults are donating organs. Although short-term outcomes are similar in older versus younger transplant recipients, older donor or recipient age is associated with inferior long-term outcomes. However, age is often a proxy for other factors that might predict poor outcomes more strongly and better identify patients at risk for adverse events. Approaches to transplantation in older adults vary across programs, but despite recent gains in access and the increased use of marginal organs, older patients remain less likely than other groups to receive a transplant, and those who do are highly selected. Moreover, few studies have addressed geriatric issues in transplant patient selection or management, or the implications on health span and disability when patients age to late life with a transplanted organ. This paper summarizes a recent trans-disciplinary workshop held by ASP, in collaboration with NHLBI, NIA, NIAID, NIDDK and AGS, to address issues related to kidney, liver, lung, or heart transplantation in older adults and to propose a research agenda in these areas.

Choice of induction regimens on the risk of cytomegalovirus infection in donor-positive and recipient-negative kidney transplant recipients

BACKGROUND

Late occurrence of cytomegalovirus (CMV) infection remains a concern in CMV-seronegative kidney and/or pancreas transplant recipients of CMV-seropositive organs (donor positive/recipient negative, D+/R-) despite the use of prophylaxis. We investigated the impact of various antibody induction regimens on CMV infection in this group of patients.

METHODS

A total of 254 consecutive D+/R- kidney and/or pancreas transplant patients were studied. The induction agents rabbit anti-thymocyte globulin (rATG) or basiliximab were used according to the center practice. All patients received prophylaxis with valganciclovir (VGCV) for either 3 or 6 months. The occurrence of CMV infection was confirmed by positive DNA viremia. Multivariate Cox regression analyses were performed to determine risk factors for CMV infection.

RESULTS

The cumulative incidence of CMV infection was 58, 112, and 59 cases per 1000 patient-years for patients who received no antibody induction, induction with rATG, or basiliximab induction, respectively (P=0.02). The use of rATG but not basiliximab was associated with an increased risk for CMV infection (adjusted hazard ratio [AHR] 2.13, 95% confidence interval [CI] 1.24-3.54, P=0.006). Acute rejection and its treatment with rATG were not associated with an increased risk for CMV infection when an additional course of VGCV was given following the treatment. Longer duration of prophylaxis was associated with a reduced risk for CMV infection (AHR 0.54, 95% CI 0.33-0.87, P=0.011).

CONCLUSIONS

Induction with rATG is associated with increased risk of CMV infection. Longer duration of prophylaxis is beneficial.

Influence of recipient race on the outcome of simultaneous pancreas and kidney transplantation

Racial differences on the outcome of simultaneous pancreas and kidney (SPK) transplantation have not been well studied. We compared mortality and graft survival of African Americans (AA) recipients to other racial/ethnic groups (non-AA) using the national data. We studied a total of 6585 adult SPK transplants performed in the United States between January 1, 2000 and December 31, 2007. We performed multivariate logistic regression analyses to determine risk factors associated with early graft failure and immune-mediated late graft loss. We used conditional Kaplan-Meier survival and multivariate Cox regression analyses to estimate late death-censored kidney and pancreas graft failure and death between the groups. Although there was no racial disparity in the first 90 days, AA patients had 38% and 47% higher risk for late death-censored kidney and pancreas graft failure, respectively (p = 0.006 and 0.001). AA patients were twice more likely to lose the kidney and pancreas graft due to rejection (OR 2.31 and 1.86, p = 0.002 and 0.008, respectively). Bladder pancreas drainage was associated with inferior patient survival (HR 1.42, 95% CI 1.15, 1.75, p = 0.001). In the era of modern immunosuppression, AA SPK transplant patients continue to have inferior graft outcome. Additional studies to explore the mechanisms of such racial disparity are warranted.

BAFF is increased in renal transplant patients following treatment with alemtuzumab

Alemtuzumab is a monoclonal antibody that depletes T and B cells and is used as induction therapy for renal transplant recipients. Without long-term calcineurin inhibitor (CNI) therapy, alemtuzumab-treated patients have a propensity to develop alloantibody and may undergo antibody-mediated rejection (AMR). In pursuit of a mechanistic explanation, we analyzed peripheral B cells and serum of these patients for BAFF (Blys) and BAFF-R, factors known to be integral for B-cell activation, survival, and homeostasis. Serum BAFF levels of 22/24 alemtuzumab-treated patients were above normal range, with average levels of 1967 pg/mL compared to 775 pg/mL in healthy controls (p = 0.006). BAFF remained elevated 2 years posttransplant in 78% of these patients. BAFF-R on CD19(+) B cells was significantly downregulated, suggesting ligand/receptor engagement. BAFF mRNA expression was increased 2-7-fold in CD14(+) cells of depleted patients, possibly linking monocytes to the BAFF dysregulation. Addition of recombinant BAFF to mixed lymphocyte cultures increased B-cell activation to alloantigen, as measured by CD25 and CD69 coexpression on CD19(+) cells. Of note, addition of sirolimus (SRL) augmented BAFF-enhanced B-cell activation whereas CNIs blocked it. These data suggest associations between BAFF/BAFF-R and AMR in alemtuzumab-treated patients.

Collapsing focal segmental glomerulosclerosis in a liver transplant recipient on alendronate

We describe a case of collapsing focal segmental glomerulosclerosis and severe kidney dysfunction in a liver transplant recipient after the initiation of alendronate for osteopenia. In view of the increasing incidence of chronic kidney disease in long-term liver transplant patients, bisphosphonates need to be used with caution in these patients. The usefulness of bisphosphonates for the prevention of early bone loss after liver transplantation is increasingly reported. However, there is little information on the safety and efficacy of these drugs when used in the later stages of liver transplant, particularly in the presence of chronic kidney disease. Bisphosphonates are excreted unchanged via the kidneys after reaching the systemic circulation. Some cases of severe kidney injury, in particular collapsing focal segmental glomerulosclerosis, have been described that are associated with the use of pamidronate. Alendronate, a widely used bisphosphonate in transplant patients, has not been related to kidney toxicity. We describe a case of collapsing focal segmental glomerulosclerosis and severe kidney dysfunction in a liver transplant recipient soon after the initiation of alendronate for osteopenia. Possible pathogenetic mechanisms are discussed. In view of the increasing incidence of chronic kidney disease in long-term liver transplant patients, bisphosphonate need to be used with caution in patients with a low glomerular filtration rate.

Outcome of renal transplantation in fibrillary glomerulonephritis

Fibrillary glomerulonephritis (FGN) is a rare but progressive glomerular disease usually with end-stage renal disease (ESRD) developing within months or few years following the diagnosis. Little is known about the outcome of renal transplantation in patients with ESRD due to FGN. We report four patients with FGN who received renal allografts. Two patients developed recurrent FGN in their grafts. One patient was diagnosed to have recurrent FGN 9 years post-transplant, and lost his graft 4 years thereafter. Another patient had recurrent disease 2 years post-transplant but has stable graft function after 7 years. One patient died with normal renal allograft function 7 years following transplantation. The fourth patient has chronic transplant nephropathy 34 months post-transplant without evidence of recurrent FGN. A literature review revealed 10 additional patients who received 11 renal allografts due to ESRD caused by FGN. Four of these 10 patients had biopsy-proven recurrence (one patient in two subsequent grafts), but this caused graft loss only in 2 patients 56 months and 7 years post-transplant, respectively. The earliest recurrence was diagnosed 2 years post-transplant. We conclude that although the recurrence rate of FGN in renal transplants is high (around 50%), the recurrent disease has a relatively benign course and prolonged graft survival is possible.

Shorter waiting times for hepatitis C virus seropositive recipients of cadaveric renal allografts from hepatitis C virus seropositive donors

INTRODUCTION

The purposes of this study were: 1) to analyze the early results of cadaveric renal transplantation from either hepatitis C virus seropositive (HCV+ ) or hepatitis C virus seronegative (HCV-) donors into HCV + recipients; and 2) to determine whether HCV+ patients with end-stage renal disease (ESRD) might benefit from receiving renal allografts from HCV + donors.

METHODS

From January 1997 to June 1999, 28 patients with ESRD and HCV infection underwent 29 cadaveric renal transplants. The data were reviewed retrospectively. Nineteen of the renal transplants were performed with allografts obtained from 15 HCV + donors and 10 with allografts obtained from 10 HCV- donors. The median follow-up was 16.2 months, with an average of 15.4+/-2 months.

RESULTS

Recipients of HCV + renal allografts had shorter waiting times for transplantation. On average, patients who received a kidney from HCV + donors were transplanted 9+/-3 months after being placed on the transplant list, compared to 29+/-3 months for patients who received a kidney from a HCV- donor. Shorter waiting times were noted in every blood type group. There were no significant differences in rejection episodes, infectious complications, renal function, liver function, graft survival, or patient survival.

CONCLUSIONS

The use of renal allografts from HCV + donors for HCV + recipients shortens the waiting time for these patients, with no short-term differences in renal and liver function, graft loss, or patient survival.

Delayed graft function: immediate and late impact

Delayed graft function remains a frequent problem after renal transplantation, which is often associated with subsequent graft failure. The major risks for delayed graft function are incurred during organ procurement, preservation, and transplantation, and are predominated by ischemic injury. The cofactors associated with delayed graft function that lead to subsequent poor outcome include early acute rejection as well as immunologic risk factors for rejection, such as presensitization, human leukocyte antigen mismatch, and previous loss of graft. Numerous diagnostic and therapeutic approaches have been assessed in recent years, but predicting or modifying adverse outcomes associated with delayed graft function in a given patient remains unreliable.

[Perception of anxiety in patients requesting anonymous HIV testing]

To determine the manifestations of anxiety in subjects seeking anonymous HIV testing and the aptitude of professionals to perceive it, we administered a semi-structured questionnaire to 481 persons, 281 before and 200 after instructing the practitioners to better decode anxiety during the consultation. The perception of anxiety by the care-givers was analyzed using the Covi scale. The results show that subjects requesting an HIV test often report stressful relational events. Their anxiety its often underestimated by the care-givers, and aptitude to recognise the patient's emotions can be improved. Prevention and quality of counselling depend on correct perception of the emotions which prompt the subject to request a test.