Desensitization Offers Hope to Highly HLA-Sensitized Patients for a Longer Life Expectancy After Incompatible Kidney Transplant

Desensitization using IVIG alone for living-donor kidney transplant: impact on donor-specific antibodies

INTRODUCTION

Sensitization to human leukocyte antigen is a barrier to. Few data have been published on desensitization using polyvalent human intravenous immunoglobulin (IVIG) alone.

METHODS

We retrospectively reviewed the of 45 patients with a positive complement-dependent cytotoxicity crossmatch (CDCXM) or flow cytometry crossmatch (FCXM) against living donors from January 2003 to December 2014. Of these, 12 were excluded. Patients received monthly IVIG infusions (2 g/kg) only until they had a negative T-cell and B-cell FCXM.

RESULTS

During the 33 patients, 22 (66.7%) underwent living donor kidney transplantation, 7 (21.2%) received a deceased donor graft, and 4 (12.1%) did not undergo transplantation. The median class I and II panel reactive antibodies for these patients were 80.5% (range 61%-95%) and 83.0% (range 42%-94%), respectively. Patients (81.8%) had a positive T-cell and/or B-cell CDCXM and 4 (18.2%) had a positive T-cell and/or B-cell FCXM. Patients underwent transplantation after a median of 6 (range 3-16). The median donor-specific antibody mean fluorescence intensity sum was 5057 (range 2246-11,691) before and 1389 (range 934-2492) after desensitization (p = 0.0001). Mean patient follow-up time after transplantation was 60.5 (SD, 36.8) months. Nine patients (45.0%). Death-censored graft survival at 1, 3, and 5 years after transplant was 86.4, 86.4, and 79.2%, respectively and patient survival was 95.5, 95.5, and 83.7%, respectively.

CONCLUSIONS

Desensitization using IVIG alone is an effective strategy, allowing successful transplantation in 87.9% of these highly sensitized patients.

Kidney transplantation in highly sensitized patients

BACKGROUND

Desensitization, a term loosely referring to a collection of antibody reduction and B-cell depletional therapies aimed at improving rates of transplantation in highly HLA and ABO-incompatible transplant recipients, has seen significant growth in the last decade. Advancements relate to an increasing unmet medical need for FDA-approved therapies, advancements in antibody detection methodologies and improved renal pathological assessments of antibody-mediated rejection (ABMR).

SOURCES OF DATA, AREAS OF AGREEMENT AND CONTROVERSY

Data reviewed include collective summaries of experience with high-dose intravenous immunoglobulin (IVIG), B-cell depletion with rituximab and the use of plasma exchange with low-dose IVIG. Consensus suggests that these protocols are the most commonly used while experiences with other agents (i.e. bortezomib) are evolving. Controversy exists as to the extent of resources required, expense and outcomes of desensitization protocols.

GROWING POINTS OR AREAS TIMELY FOR DEVELOPING RESEARCH

Here we review and synthesize data from evolving protocols and summarize developments of novel biologics aimed at modification of B-cells, antibodies and complement activation which will likely improve desensitization and treatment of ABMR.

Achieving incompatible transplantation through desensitization: current perspectives and future directions

The application of life-saving transplantation is severely limited by the shortage of organs, and histoincompatibility. To increase transplant rates in sensitized patients, new protocols for HLA and blood type incompatible (ABOi) desensitization have emerged. These approaches require significant desensitization using intravenous immunoglobulin, rituximab and plasma exchange. In addition, the development of donor-specific antibody responses post transplant is the major cause of allograft failure with return to dialysis. This increases patient morbidity/mortality and cost. Immunotherapeutic agents used for desensitization evolved from drug development in oncology and autoimmune diseases. Currently, there is a renaissance in development of novel drugs likely to improve antibody reduction in transplantation. These include agents that inactivate IgG molecules, anticytokine antibodies, costimulatory molecule blockade, anticomplement agents and therapies aimed at the plasma cell.

Successful transplantation of kidney allografts in sensitized rats after syngeneic hematopoietic stem cell transplantation and fludarabine

Current methods to remove donor-specific HLA antibody (DSA) from sensitized patients remain imperfect. We tested novel approaches to desensitization using an animal model of allogeneic sensitization with skin grafts from dark agouti (DA) to Lewis rats. At the peak IgG alloantibody response we transplanted DA kidneys into nephrectomized Lewis recipients (n = 6) and all died within 10 days from antibody-mediated rejection (AMR). Allogeneic hematopoietic stem cell transplants (HSCT) from DA donors failed to engraft after lethal or sub-lethal irradiation. Sensitized rats given lethal irradiation plus syngeneic green fluorescent protein (GFP) + HSCT had repopulation of blood, spleen, thymus and lymph nodes by GFP+ cells. At 2 months after HSCT, serum DSA levels were reduced 60-70% and DSA (IgG) production in cultured splenocytes was also significantly decreased. However, there was only a modest improvement in graft survival from an average of 6.5 to 13.9 (n = 9) days. Adding seven daily doses of fludarabine to the preconditioning regimen resulted in long-term survival (>90 days) in 7 out of 10 rat kidney allografts. We conclude that syngeneic HSCT performed after preconditioning with irradiation and fludarabine can reduce DSA, prevent DSA rebound and AMR, enabling successful transplantation in animals with strong antibody reactivity to the donor MHC.

Therapeutic plasma exchange for the treatment of pediatric renal diseases in 2013

Therapeutic plasma exchange is an extracorporeal treatment modality that removes systemic circulating pathologic factors or replaces absent plasma components and plays a role in many nephrologic conditions. It presents a number of technical challenges in the pediatric population but has become an increasingly common practice in pediatric nephrology over the past several decades. While prospective evidence is often lacking, our increased understanding of the molecular pathogenesis underlying many pediatric renal diseases provides sound reasoning for the use of plasma exchange in treating these conditions. This review will present the currently accepted indications for plasma exchange in children, the technical aspects of the procedure and its potential complications.