Sensitization in Transplantation: Assessment of Risk (STAR) 2017 Working Group Meeting Report

The presence of preexisting (memory) or de novo donor-specific HLA antibodies (DSAs) is a known barrier to successful long-term organ transplantation. Yet, despite the fact that laboratory tools and our understanding of histocompatibility have advanced significantly in recent years, the criteria to define presence of a DSA and assign a level of risk for a given DSA vary markedly between centers. A collaborative effort between the American Society for Histocompatibility and Immunogenetics and the American Society of Transplantation provided the logistical support for generating a dedicated multidisciplinary working group, which included experts in histocompatibility as well as kidney, liver, heart, and lung transplantation. The goals were to perform a critical review of biologically driven, state-of-the-art, clinical diagnostics literature and to provide clinical practice recommendations based on expert assessment of quality and strength of evidence. The results of the Sensitization in Transplantation: Assessment of Risk (STAR) meeting are summarized here, providing recommendations on the definition and utilization of HLA diagnostic testing, and a framework for clinical assessment of risk for a memory or a primary alloimmune response. The definitions, recommendations, risk framework, and highlighted gaps in knowledge are intended to spur research that will inform the next STAR Working Group meeting in 2019.

Individualization of immunosuppressive therapy. III. Sirolimus associated with a reduced incidence of malignancy

OBJECTIVE

We examined the occurrence of neoplasms among 1008 renal transplant recipients treated with a sirolimus-cyclosporine (CsA) +/- prednisone (Pred) regimen.

METHODS

A comprehensive database of demographic, laboratory, clinical, and histopathologic features of these patients all followed in our transplant center was analyzed using Student t test and Mann-Whitney U test for continuous and chi-square test for categorical variables. Comparisons were performed with information in the Israel Penn International Transplant Tumor Registry (IPITTR).

RESULTS

During the mean patient follow-up of 62.3 +/- 26.1 months (range 27.1 to 131), 36 tumors occurred in 35 patients (3.6%) at 32.5 +/- 29.8 months. The most common neoplasms were skin tumors (2.4%), a value that was significantly lower than the 6% rate observed with CsA-azathioprine-Pred treatment. Also, the 0.4% incidence of posttransplant lymphoproliferative disorders and 0.2% incidence of renal cell carcinomas were less than half of those previously reported with a combination of tacrolimus and mycophenolate mofetil. The distribution of tumor types was similar to that reported to the IPITTR. The mean trough drug concentrations in affected recipients at the time of diagnosis were within the putative target ranges.

CONCLUSION

Renal transplant recipients treated with the sirolimus-CsA +/- Pred combination showed a low incidence of tumors of similar types as those encountered with other regimens.

Complications and monitoring of OKT3 therapy

Complications of OKT3 therapy were studied in 122 treatment episodes in renal allograft recipients (83 for rejection treatment, 39 for immunosuppression induction). A febrile first-dose reaction to OKT3 was common; no severe pulmonary complications were encountered. Other toxicities of OKT3 therapy were observed later in the treatment course. Most severe were the occurrence of aseptic meningitis in four patients (3%), and seizures in eight (6%). Seizures occurred only when OKT3 was given to patients with nonfunctioning grafts due to acute tubular necrosis. Infections were the only significant late adverse sequelae of OKT3 therapy and occurred more frequently after multiple exposures to the drug (53%) than after a single exposure (22%). IgG antibodies to OKT3 developed after 45% of exposures to the drug in the 74 patients in whom appearance of anti-OKT3 antibodies was monitored. In two patients (3%), anti-OKT3 antibodies were detected before the end of the OKT3 treatment course, neutralizing the immunosuppressive property of the drug. In five patients (7%), strong anti-OKT3 antibody responses were present at the time of subsequent rejection, which precluded reuse of the drug. In 17 other cases, no or only a weak anti-OKT3 response was detectable at the time of rejection following initial OKT3 exposure. Retreatment with OKT3 was successful in reversing rejection in 15 cases (88%). No untoward sequelae were noted after reexposure to OKT3, except the high incidence of subsequent infections.