Rabbit anti-thymocyte globulin (rATG) versus IL-2 receptor antagonist induction therapies in tacrolimus-based immunosuppression era: a meta-analysis

The use of lymphocyte-depleting antibodies in specific populations of kidney transplant recipients: A systematic review and meta-analysis

BACKGROUND

Recommendations of the use of antibody induction treatments in kidney transplant recipients (KTR) are based on moderate quality and historical studies. This systematic review aims to reevaluate, based on actual studies, the effects of different antibody preparations when used in specific KTR subgroups.

METHODS

We searched MEDLINE and CENTRAL and selected randomized controlled trials (RCT) and observational studies looking at different antibody preparations used as induction in KTR. Comparisons were categorized into different KTR subgroups: standard, high risk of rejection, high risk of delayed graft function (DGF), living donor, and elderly KTR. Two authors independently assessed the risk of bias.

RESULTS

Thirty-seven RCT and 99 observational studies were finally included. Compared to anti-interleukin-2-receptor antibodies (IL2RA), anti-thymocyte globulin (ATG) reduced the risk of acute rejection at two years in standard KTR (RR 0.74, 95%CI 0.61-0.89) and high risk of rejection KTR (RR 0.55, 95%CI 0.43-0.72), but without decreasing the risk of graft loss. We did not find significant differences comparing ATG vs. alemtuzumab or different ATG dosages in any KTR group.

CONCLUSIONS

Despite many studies carried out on induction treatment in KTR, their heterogeneity and short follow-up preclude definitive conclusions to determine the optimal induction therapy. Compared with IL2RA, ATG reduced rejection in standard-risk, highly sensitized, and living donor graft recipients, but not in high DGF risk or elderly recipients. More studies are needed to demonstrate beneficial effects in other KTR subgroups and overall patient and graft survival.

ABO incompatibility in renal transplantation

ABO blood group incompatibility (ABO-I) was historically considered an absolute contraindication to kidney transplantation due to the significant risk of acute antibody-mediated rejection and early graft loss. Nevertheless, the urge to minimize the gap between the candidates’ number on the waitlist for kidney transplants and the available kidney donors encourage investigation into finding ways to use organs from ABO-I kidney donors, especially in the era of using more potent immunosuppression therapies. This review aims to discuss a general overview of ABO-I kidney transplantation and the different protocols adopted by some transplant centers to meaningfully overcome this barrier.

Clinical Outcomes of Older Kidney Transplant Recipients

BACKGROUND

Older kidney transplant recipients (OKTR) are vulnerable to infections and AKI, often prompting hospitalization. This study elucidates etiology of hospitalizations, AKI, and outcomes in OKTR.

METHODS

Retrospective study of 500 patients age ≥ 60, who underwent kidney transplantation from 2005-2015. Demographic, transplant, and outcomes data were collected.

RESULTS

OKTR had mean age 66 years; 59% males and 50% African Americans. 62% had at least one hospitalization post-transplant. Predictors of hospitalization were DGF, DM, panel reactive antibodies (PRA), dialysis duration. Hospitalization was mostly due to infection and surgical complications. Average length of stay was 6.4 days. OKTR with at least one hospitalization had 84% higher risk for graft loss (p=0.001). 56% of older kidney transplant recipients had at least one AKI episode post-transplant. Predictors of AKI included DGF, older, African American donor, and tacrolimus variability. The most common etiologies for AKI were infection, dehydration, and GI complications. OKTR with at least one AKI episode had 2.6-fold higher risk for graft loss (p<0.001).

CONCLUSIONS

Post-transplant hospitalization and AKI in OKTR significantly impact graft survival. Addressing comorbidities and risks in the pre-transplant and outpatient setting may help alleviate burden of hospitalization and risk of AKI in OKTR and improve graft outcomes.

18F-FDG PET/CT for Evaluation of Post-Transplant Lymphoproliferative Disorder (PTLD)

Post-transplant lymphoproliferative disorders (PTLD) are a spectrum of heterogeneous lymphoproliferative conditions that are serious and possibly fatal complications after solid organ or allogenic hematopoietic stem cell transplantation. Most PTLD are attributed to Epstein-Barr virus reactivation in B-cells in the setting of immunosuppression after transplantation. Early diagnosis, accurate staging, and timely treatment are of vital importance to reduce morbidity and mortality. Given the often nonspecific clinical presentation and disease heterogeneity of PTLD, tissue biopsy and histopathological analysis are essential to establish diagnosis and most importantly, determine the subtype of PTLD, which guides treatment options. Advanced imaging modalities such as ¹⁸F-FDG PET/CT have played an increasingly important role and have shown high sensitivity and specificity in detection, staging, and assessing treatment response in multiple clinical studies over the last two decades. However, larger multicenter prospective validation is still needed to further establish the clinical utility of PET imaging in the management of PTLD. Significantly, new hybrid imaging modalities such as PET/MR may help reduce radiation exposure, which is especially important in pediatric transplant patients.

Relationship between rabbit anti-thymocyte globulin and development of PTLD and its aggressive form in renal transplant population

Introduction

The aim of our study is to explore the relationship of rabbit anti-thymocyte globulin (R-ATG) on development of post-transplant lymphoproliferative disease (PTLD) and its aggressive forms (monomorphic PTLD and Hodgkin lymphoma) in renal transplant recipients.

Methodology

All patients diagnosed with PTLD post-renal transplant in the United States’ Organ Procurement and Transplantation Network from 2003 till 2013 and followed up till 2017 were retrospectively reviewed. Multi-variable logistic regression analysis assessed association of R-ATG to development of PTLD and its aggressive form.

Results

Risk of developing PTLD post renal transplant is 1.35%. In comparison to interleukin-2 blocker induction therapy, R-ATG is associated with increased risk of development of PTLD (Odds Ratio = 1.48, confidence interval ranges from 1.04 to 2.11, p = .02) and is associated with higher risk of development of aggressive PTLD (Odds Ratio = 1.83, confidence interval ranges from 1.001 to 3.34, p = .04).

Conclusion

We conclude that R-ATG induction is associated with a higher risk of PTLD and its aggressive form (monomorphic PTLD and Hodgkin lymphoma). Careful monitoring for development of PTLD in renal transplant recipients receiving R-ATG induction therapy is advised.