Management of Plasma Cell-Rich Acute Rejection in Living-Related Kidney Transplant: Role of Proteasome Inhibitor

Successful Treatment of Plasma Cell-Rich Acute Rejection Using Bortezomib: A Case Report

Plasma cell-rich acute rejection (PCAR), a relatively rare subtype of acute allograft rejection, is usually associated with a significantly lower treatment response rate and a higher graft failure rate. PCAR is characterized by the presence of more than 10% of plasma cells out of all graft infiltrating cells, with approximately 40%-60% of PCAR resulting in graft failure within a year. Currently, there is no gold standard for the effective treatment of PCAR. This case report demonstrates the potential treatment effect of bortezomib in PCAR. A 37-year-old woman with reflux nephropathy received a kidney transplant from a brain-dead kidney donor. The patient presented with an acute kidney injury with a serum creatinine level over 4 mg/dL 4 months after the surgery. The allograft biopsy showed acute T cell-mediated rejection (TCMR), Grade IIA, plasma cell-rich variant. There were diffuse polyclonal plasma cells infiltrating the renal parenchyma with marked tubulitis and focal endarteritis. She received a methylprednisolone pulse of 500 mg daily x3, followed by thymoglobulin (rATG) at 4.2 mg/kg. However, a repeated biopsy after 2 months showed persistent plasma cells infiltrate with increased interstitial fibrosis with tubular atrophy. Then, the patient was given one cycle of bortezomib with a total of four subcutaneous injections and continued immunosuppressants of tacrolimus, mycophenolate mofetil, and prednisone. Following the treatment, the patient's serum creatinine level trended down to 2 mg/dL, and a second repeat biopsy after 4 months showed a significant treatment effect with complete resolution of interstitial inflammation and decreased chronicity. Bortezomib is a proteasome inhibitor that prevents cell proliferation by inducing apoptosis in plasma cells and has shown great promise as a therapeutic agent for multiple myeloma. Our case suggests that bortezomib can also be used as a potential therapeutic intervention for patients with PCAR.

Effectiveness of international virtual training on biorisk management in the context of COVID-19

Introduction

The COVID-19 pandemic has resulted in enormous increases in laboratory activities to keep pace with diagnostic testing and research efforts. However, traditional training, technical assistance, and capacity-building approaches were disrupted by the travel and movement restrictions put in place to control the spread of the disease. To address the needs of laboratorians and managers to conduct laboratory activities safely and securely during the pandemic, a highly interactive virtual training (IVT) workshop on biorisk management during COVID-19 was conducted through active learning strategies that connected speakers with participants. The objective of the training was to increase the basic knowledge and standards of biosafety and biosecurity practices, risk assessment, and control measures with reference specifically to the context of the COVID-19 pandemic and apply a rigorous evaluation methodology to assess the effectiveness of the IVT. The training covered a broad range of topics and encompassed national to international guidelines.

Methods

Participants were selected through official channels at the national level, focusing on institutions within Pakistan. The sessions included lectures from international experts in biorisk management concepts, and incorporated poll questions as well as pre- and post-tests and feedback on the speakers' knowledge and presentation skills, to increase interactivity. The pre- and post-test comprised similar multiple-choice questions and provided to every participant to ascertain the impact of the training on awareness and knowledge of biorisk management topics and concepts, and results were compared using paired t-tests. For feedback on the speakers, participants were asked to submit their ratings measured on a five-point Likert scale. The reliability of the Likert scale was estimated using Cronbach's alpha. Analyses were performed using Microsoft Excel and SPSS version 23.

Results

In total, 52 individuals from different laboratories across Pakistan and Pakistani students from abroad (China) as well participated in at least one session of the IVT. The participants' pre- and post-test scores showed a significant increase in knowledge and awareness (p < 0.001). The obtained Cronbach's alpha score was >0.8, indicating high reliability of the generated feedback on the IVT approach and speakers.

Conclusion

The IVT on biosafety and biosecurity in the context of the COVID-19 pandemic proved beneficial for laboratory professionals and could be a useful model to continue in the future for raising awareness and knowledge.

Plasma cell-rich related acute rejection in kidney transplant: A case report and review of the literature

RATIONALE

Plasma cell-rich acute rejection (PCAR), a subtype of T cell-mediated rejection, is a relatively rare type of acute allograft rejection, that is usually associated with a higher rate of graft failure. However, it is difficult to diagnose PCAR precisely.

PATIENT CONCERNS

A 45-year-old woman who had received a kidney transplant presented with acute kidney injury and uremic symptoms approximately 1 year after transplantation.

DIAGNOSIS

A renal biopsy was performed and pathological examination revealed marked inflammation with abundant plasma cells in areas within interstitial fibrosis and tubular atrophy. The patient was diagnosed with PCAR and chronic active T cell-mediated rejection (CA-TCMR) grade IA.

INTERVENTIONS

Immunosuppressants were administered as tacrolimus (2 mg twice daily), mycophenolate mofetil (250 mg twice daily), and prednisolone (15 mg/day) for suspected PCAR.

OUTCOMES

The patients showed rapid deterioration in kidney function and reached impending graft failure.

LESSONS

PCAR is often associated with poor graft outcome. The high variability in tacrolimus levels could contribute to poor patient outcomes, leaving aggressive immunosuppressive therapy as the remaining choice for PCAR treatment.

Alloimmune versus autoimmune hepatitis following liver transplantation

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Optimal Immunosuppression Strategy in the Sensitized Kidney Transplant Recipient

Patients with previous sensitization events against anti-human leukocyte antigens (HLA) often have circulating anti-HLA antibodies. Following organ transplantation, sensitized patients have higher rates of antibody-mediated rejection (AMR) compared to those who are non-sensitized. More stringent donor matching is required for these patients, which results in a reduced donor pool and increased time on the waitlist. Current approaches for sensitized patients focus on reducing preformed antibodies that preclude transplantation; however, this type of desensitization does not modulate the primed immune response in sensitized patients. Thus, an optimized maintenance immunosuppressive regimen is necessary for highly sensitized patients, which may be distinct from non-sensitized patients. In this review, we will discuss the currently available therapeutic options for induction, maintenance, and adjuvant immunosuppression for sensitized patients.

The Implications of B-lineage Cells in Kidney Allografts

The majority of cells comprising the inflammatory infiltrates in kidney allografts undergoing acute and/or chronic rejection are typically T cells and monocyte/macrophages with B cells, plasma cells, and eosinophils accounting for <5%. In a significant minority of biopsies, B lineage cells (B cells and/or plasma cells) may be found more abundantly. Although plasma cell infiltrates tend to be more diffuse, B cells tend to aggregate into nodules that may mature into tertiary lymphoid organs. Given the ability to target B cells with anti-CD20 monoclonal antibodies and plasma cells with proteasome inhibitors and anti-CD38 monoclonal antibodies, it is increasingly important to determine the significance of such infiltrates. Both cell types are potential effectors of rejection, but both also have a tolerizing potential. B cell infiltrates have been associated with steroid resistance and reduced graft survival in some studies but not in others, and their presence should not prompt automatic depletional therapy. Plasma cell-rich infiltrates tend to occur later, may be associated with cell-mediated and/or antibody-mediated rejection, and portend an adverse outcome. Viral infection and malignancy must be ruled out. Randomized controlled trials are needed to determine the appropriateness of specific therapy when B cells and/or plasma cells are found. No strong therapeutic recommendations can be made at this time.

The Preliminary Results of Bortezomib Used as A Primary Treatment for An Early Acute Antibody-Mediated Rejection after Kidney Transplantation-A Single-Center Case Series

Proteasome inhibitor bortezomib has been used in the treatment of refractory cases of acute and chronic antibody-mediated rejection (AMR) in kidney transplant recipients. However, its efficacy and safety as a primary treatment for early AMR has been scarcely investigated. We herein present our preliminary experience with bortezomib- and plasmapheresis-based primary treatment for early AMR. Thirteen patients transplanted between October 2015 and September 2019 were treated (starting at median 19th post-transplant day) with bortezomib/plasmapheresis protocol for early biopsy-proven AMR. Twelve out of thirteen patients received 4 doses and one patient recieved 3 doses of bortezomib (1.3 mg/m² per dose). In 11/13 patients, 4–7 concomitant plasmapheresis sessions were performed, with or without intravenous immunoglobulin (IVIG). Of note, rituximab was not used in all study patients. The kidney graft and patient survival were 100%. The mean 3-month estimated glomerular filtration rate (eGFR) was 55.3 (95%CI: 44.9–65.8) mL/min/1.73m², 8/13 patients completed 12-month follow-up with mean eGFR 60.4 (45.4–75.4) mL/min/1.73m², and 6/13 patients completed a 24-month follow-up period with mean eGFR 73.9 (56.7–91.1) mL/min/1.73m². Neutropenia < 1 G/L was observed in one patient, third or fourth grade thrombocytopenia in two patients, and eleven patients needed a blood transfusion (median: 2 units/patient). The mid-term results of a primary bortezomib-based treatment for kidney AMR showed its non-inferiority as compared to preceding regimens and acceptable safety. However, our data should be validated in a multicenter randomized trial.

Bortezomib Eliminates Plasma Cells From a Renal Graft in Plasma Cell-Rich Acute Rejection

Plasma cell-rich acute rejection (PCAR) and antibody-mediated rejection (ABMR), for which a standard treatment has not yet been established, are associated with poor graft survival after kidney transplantation. Here, we report a case series of 3 Japanese patients diagnosed with PCAR accompanied by ABMR. Steroid pulse therapy and rabbit antithymocyte globulin, plasma exchange, intravenous immunoglobulin, and rituximab therapies were sequentially performed in the first case. A graft biopsy after each treatment showed that plasma cell infiltration persisted. Five months after the initiation of rejection therapy, the patient was subjected to bortezomib therapy, which led to the partial elimination of plasma cells from the graft. However, the graft function gradually deteriorated, and hemodialysis treatment was warranted. In the other 2 cases, the patients received the same combination of therapy including bortezomib within a short period. Graft biopsies performed subsequently showed a marked decrease in the number of infiltrated plasma cells, and stabilization of renal graft function was achieved in both cases. Bortezomib, which targets plasma cells, is a potent drug that eliminates infiltrated plasma cells from the graft in PCAR. Thus, in addition to conventional therapy comprising plasma exchange, intravenous immunoglobulin, and rituximab against ABMR, bortezomib may be necessary to administer without any delay to control PCAR.