Cytomegalovirus and HLA-A, B, and DR locus interactions: impact on renal transplant graft survival

Study Design: HLA-A*02-Chimeric Antigen Receptor Regulatory T Cells in Renal Transplantation

Introduction

Cell therapy with regulatory T cells (Tregs) in solid organ transplantation is a promising approach for the prevention of graft rejection and induction of immunologic tolerance. Previous clinical studies have demonstrated the safety of Tregs in renal transplant recipients. Antigen-specific Tregs, such as chimeric antigen receptor (CAR)-Tregs, are expected to be more efficacious than polyclonal Tregs in homing to the target antigen. We have developed an autologous cell therapy (TX200-TR101) where a human leukocyte antigen (HLA) class I molecule A^∗02 (HLA-A^∗02)-CAR is introduced into autologous naive Tregs from a patient with HLA-A^∗02-negative end-stage renal disease (ESRD) awaiting an HLA-A^∗02-positive donor kidney.

Methods

This article describes the design of the STEADFAST study, a first-in-human, phase I/IIa, multicenter, open-label, single-ascending dose, dose-ranging study to assess TX200-TR101 in living-donor renal transplant recipients. Up to 15 transplant recipients will receive TX200-TR101 and will be followed up for a total of 84 weeks post-transplant, alongside a control cohort of up to 6 transplant recipients. All transplant recipients will receive a standard of care immunosuppressive regimen, with the intent of intensified tapering of the regimen in the TX200-TR101 cohort.

Results

The primary end point is the incidence and severity of treatment-emergent adverse events (AEs) within 28 days post–TX200-TR101 infusion. Other end points include additional safety parameters, clinical and renal outcome parameters, and the evaluation of biomarkers.

Conclusion

The STEADFAST study represents the next frontier in adoptive cell therapies. TX200-TR101 holds great potential to prevent immune-mediated graft rejection and induce immunologic tolerance after HLA-A^∗02-mismatched renal transplantation.

The association of cytomegalovirus sero-pairing with outcomes and costs following cadaveric renal transplantation prior to the introduction of oral ganciclovir CMV prophylaxis

Cytomegalovirus (CMV) is an important cause of morbidity, mortality and cost in cadaveric renal transplantation. This study was designed to document the clinical and economic outcomes associated with donor and recipient CMV sero-pairing. Data were drawn from the United States Renal Data System (USRDS) on 17 001 cadaveric renal transplant recipients transplanted between 1995 and 1997 with recorded donor and recipient CMV sero-status. In multivariate analysis, CMV-seropositive recipients were associated with a significantly higher incidence of delayed graft function, a lower incidence of graft loss, and lower costs than CMV-seronegative recipients. CMV-seropositive compared to seronegative donors were associated with significantly higher incidence of CMV disease, graft loss, and higher costs when transplanted into CMV-seronegative recipients. However, CMV-seronegative donors into seropositive recipients had no significant association with outcome beyond a higher incidence of CMV disease compared to CMV-seronegative donor and recipient pairs. The outcomes associated with CMV-seropositive donors and seronegative recipients call for tailored management strategies which may include avoidance of such mismatching, antiviral therapy, immunization, or modified immunosuppression.

Cytomegalovirus disease after prophylaxis with oral ganciclovir in renal transplantation: the importance of HLA-DR matching

This study assessed the incidence of cytomegalovirus (CMV) disease and associated outcomes after oral ganciclovir prophylaxis in renal transplantation. A retrospective analysis was performed of all adult renal transplant recipients at a single transplant center transplanted between August 16, 1996, and December 31, 2000. CMV disease prophylaxis included ganciclovir 1000 mg orally thrice daily prescribed for 90 d in D-/R+ cases and 180 d in D+/R- and D+/R+ cases. Forty (9.1%) of 470 patients studied were diagnosed with CMV disease, which varied significantly by CMV serostatus and number of HLA-DR matches. The highest incidence of disease, 26.2%, was in D+/R- patients with zero HLA-DR matches. Five-year graft survival was 56.8% with CMV disease compared with 79.1% without (P < 0.001). Five-year graft survival with CMV disease was 75.9% with one or two HLA-DR matches versus 16.2% with zero HLA-DR matches (P < 0.001). CMV remains an important factor in long-term graft survival after oral ganciclovir prophylaxis. However, we have observed that the adverse impact of CMV disease on graft survival is apparent only in patients with zero HLA-DR matches. These results call for the development of new CMV disease prophylaxis and treatment strategies in patients with zero HLA-DR matches. In addition, organ allocation policies discouraging combining CMV-seropositive donors and zero HLA-DR matches may be worth consideration.

Association of glycoprotein B and immediate early-1 genotypes with human leukocyte antigen alleles in renal transplant recipients with cytomegalovirus infection

BACKGROUND

Numerous risk factors for cytomegalovirus (CMV) infection or disease, or both, such as serostatus of donor and recipient, immunosuppressive regimen, or intensity of viral load, have been identified in renal transplant recipients. Additional parameters may be involved, notably, genetic variability of both host and virus, which could modulate the efficacy of the immune response.

METHODS

Active CMV infection was analyzed retrospectively in 634 renal transplant recipients, according to human leukocyte antigen (HLA)-A, HLA-B, and HLA-DR alleles; CMV serostatus; presentation of the disease; and variations in the coding sequences of glycoprotein (g) B and IE1 proteins.

RESULTS

Active infection occurred in 141 of 634 patients: seropositivity of the donor and the recipient were identified as risk factors. Patients carrying the HLA-A11, HLA-A32, or HLA-DR11 allele developed active infection more frequently, whereas none of the patients with the HLA-B16 or HLA-B55 allele was actively infected. Significant independent associations between some genotypes and particular HLA alleles were observed: gB1 was more frequent in the HLA-A24 or HLA-B7 context and underrepresented in patients with HLA-DR11; gB2 was more frequent in HLA-A32 or HLA-DR11 carriers; and an increased frequency of gB3 was observed in the HLA-A29 context. Considering the IE1-2 genotype, increased frequency was noted for HLA-A3 carriers, whereas this type was underrepresented for patients with the HLA-DR11 allele.

CONCLUSION

Data strongly suggest that differential presentation of polymorphic gB or IE peptides by HLA molecules or differential recognition by host CD8+ and CD4+ T lymphocytes, or both, should modulate immunologic response and then CMV pathogenesis in renal transplant patients.