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.

Sensitization assessment before kidney transplantation.

Kidney transplantation is the treatment of choice for patients with end stage renal disease to optimize survival, freedom from morbidity and quality of life. A fundamental aspect of the pre-transplant assessment is a thorough understanding of their immunological history and prior exposures, so that the immunological risk from a given donor can be estimated, if not quantified, in order to guide interventions to optimize transplant access and success. The methodologies available to complete this assessment have evolved rapidly, with flow cytometric based analyses now standard in many laboratories, availability of comprehensive molecular methods for HLA typing of both donors and recipients, and an increasing recognition of the vital dialogue that must occur between the HLA laboratory and transplant clinicians. This review considers the pre-transplant histocompatibility assessment journey that a recipient undertakes, from initial referral through transplantation, discussing the methodologies used, the benefits and limitations offered by current technologies, and reviewing the basics of interpretation.