Risk Evaluation and Mitigation Strategies: A Focus on Belatacept

A Pathology Experience of Posttransplant Lymphoproliferative Disorder From One Tertiary Hospital: Pathology Concepts and Diagnostic Approach

BACKGROUND

Solid organ transplantation and bone marrow/hematologic stem cell transplantation recipients face a heightened risk of developing malignancies or cancer as a result of immunosuppression. Posttransplant lymphoproliferative disorders (PTLD) are a range of disorders from benign lymphoid growth to lymphoma found post-transplant. Risk factors for PTLD include high immunosuppressive use and oncogenic effects of Epstein-Barr virus (EBV). There is a lack of comprehensive clinical and pathological documentation of PTLD cases among Saudi patients, and the available data are limited to a few case reports. As a result, a deeper understanding of this disease requires more clinicopathological information.

MATERIAL AND METHOD

In this review, we share our insights on cases diagnosed with PTLD at King Faisal Specialist Hospital and Research Center, a prominent tertiary center in the western region of Saudi Arabia, from 2005-2023.

RESULT

We have diagnosed a total of 14 cases of PTLD in our department, with an age range spanning from 3 to 62 years. These diagnoses were made based on biopsies or tumor resection procedures. The survival rate of patients is believed to be influenced by multiple factors, including histology, tumorigenesis, disease biology, and clinical stage. Additionally, Kaplan-Meier curve analysis indicates that female patients tend to have a higher estimated survival rate compared to males.

CONCLUSION

PTLD diagnosis and therapy have greatly improved in the past 20 years. PTLD is treated with reduced immunosuppression, rituximab, chemotherapy, adoptive therapy, surgery, antiviral therapy, and radiotherapy. In this study, we present our experience from a large tertiary center in the western region of Saudi Arabia. Moreover, we will go through etiology, clinical features, and pathologic morphology along with the corresponding genetics, prevention, and valid treatment options.

Infections after organ transplantation and immune response

Organ transplantation has provided another chance of survival for end-stage organ failure patients. Yet, transplant rejection is still a main challenging factor. Immunosuppressive drugs have been used to avoid rejection and suppress the immune response against allografts. Thus, immunosuppressants increase the risk of infection in immunocompromised organ transplant recipients. The infection risk reflects the relationship between the nature and severity of immunosuppression and infectious diseases. Furthermore, immunosuppressants show an immunological impact on the genetics of innate and adaptive immune responses. This effect usually reactivates the post-transplant infection in the donor and recipient tissues since T-cell activation has a substantial role in allograft rejection. Meanwhile, different infections have been found to activate the T-cells into CD₄⁺ helper T-cell subset and CD₈⁺ cytotoxic T-lymphocyte that affect the infection and the allograft. Therefore, the best management and preventive strategies of immunosuppression, antimicrobial prophylaxis, and intensive medical care are required for successful organ transplantation. This review addresses the activation of immune responses against different infections in immunocompromised individuals after organ transplantation.

Management of Hospitalized Kidney Transplant Recipients for Hospitalists and Internists

The number of kidney transplant recipients has grown incrementally over the years. These patients have a high comorbidity index and require special attention to immunosuppression management. In addition, this population has an increased risk for cardiovascular events, electrolyte abnormalities, allograft dysfunction, and infectious complications. It is vital for hospitalists and internists to understand the risks and nuances in the care of this increasingly prevalent, but also high-risk, population.

Long-Term Infectious Complications of Kidney Transplantation

Infections remain a common complication of solid-organ transplantation. Most infections in the first month after transplant are typically health care-associated infections, whereas late infections, beyond 6-12 months, are community-acquired infections. Opportunistic infections most frequently present in the first 12 months post-transplant and can be modulated on prior exposures and use of prophylaxis. In this review, we summarize the current epidemiology of postkidney transplant infections with a focus on key viral (BK polyomavirus, cytomegalovirus, Epstein-Barr virus, and norovirus), bacterial (urinary tract infections and Clostridioides difficile colitis), and fungal infections. Current guidelines for safe living post-transplant are also summarized. Literature supporting prophylaxis and vaccination is also provided.

Evaluation the Architect EBV VCA IgM, VCA IgG, and EBNA-1 IgG chemiluminescent immunoassays to assess EBV serostatus prior transplantation

Prior to transplantation of hematopoietic stem cells or solid organ, donor and recipient EBV serostatus has to be determined to assess risks of post-transplant lymphoproliferative disorders. Sensitivity of EBV Viral capsid antigens (VCA) IgG and EBV nuclear antigen-1 (EBNA-1) is critical to define past infection and a good specificity of VCA IgM is required to avoid any disqualification of cord blood (CB) units. Architect™ EBV antibody panel (Architect assay) providing a high throughput was compared to a semi-automated ELISA (Etimax assays Diasorin) to assess sensitivities and specificities of VCA and EBNA-1 IgG and VCA IgM on 419 sera collected from immunocompromised patients (n = 184) and from pregnant women who agreed to give CB cells (n = 235). Intra and inter-assay coefficient of variations ranged from 1.63% to 4.8% for VCA IgM, VCA IgG, and EBNA-1 IgG. Index of VCA IgG and IgM and EBNA IgG of the two assays were highly correlated. The concordance in the interpretation between the two assays was moderate for VCA IgM (kappa = 0.5), substantial for VCA IgG (kappa = 0.60) and good for EBNA-1 IgG (kappa = 0.75). Using serial dilutions of positive controls and in accordance with clinical results VCA IgG and EBNA IgG were detected at lower dilutions with Architect than Etimax. Conversely, 96.1% (74/77) of samples negative with Architect and positive with Etimax for VCA IgM did not have any heterophile antibodies and had VCA IgG and EBNA IgG antibodies supporting past infections. Architect™ EBV serology panel provided good sensitivities and specificities for EBV serostatus determination prior to transplantation.

Belatacept for the prophylaxis of organ rejection in kidney transplant patients: an evidence-based review of its place in therapy

BACKGROUND

Belatacept is a novel immunosuppressive therapy designed to improve clinical outcomes associated with kidney transplant recipients while minimizing use of calcineurin inhibitors (CNIs).

METHODS

We searched for clinical trials related to administration of belatacept to kidney transplant patients compared to various immunosuppression regimens, as well as for studies that utilized data from belatacept trials to validate new surrogate measures. The purpose of this review is to consolidate the published evidence of belatacept's effectiveness and safety in renal transplant recipients to better elucidate its place in clinical practice.

RESULTS

Analysis of the results from the Belatacept Evaluation of Nephroprotection and Effi-cacy as First-Line Immunosuppressive Trial (BENEFIT) study, a de novo trial that compared cyclosporine (CsA)-based therapy to belatacept-based therapy in standard criteria donors, found a significant difference in mean estimated glomerular filtration rate (eGFR) of 13-15 mL/min/1.73 m(2) and 23-27 mL/min/1.73 m(2) at 1 year and 7 years, respectively. The BENEFIT-EXT study was similarly designed with the exception that it included extended criteria donors. Renal function improved significantly for the more intensive belatacept group in all years of the BENEFIT-EXT study; however, it was not significant in the less intensive group until 5 years after transplant. Belatacept regimens resulted in lower blood pressure, cholesterol levels, and incidence of new-onset diabetes after transplant compared to CsA-based regimens. Results from conversion of CNIs to belatacept therapy, dual therapy of belatacept with sirolimus, and belatacept with corticosteroid avoidance therapy are also included in this article.

CONCLUSION

The evidence reviewed in this article suggests that belatacept is an effective alternative in kidney transplant recipients. Compared to CNI-based therapy, belatacept-based therapy results in superior renal function and similar rates of allograft survival. In terms of safety, belatacept was shown to have lower incidence of hypertension, hyperlipidemia, and diabetes; however, incidence of posttransplantation lymphoproliferative disorder and the cost of belatacept may hinder use of this medication.