Immunology of Diabetes Society T‐Cell Workshop: HLA class I tetramer‐directed epitope validation initiative T‐Cell Workshop Report—HLA Class I Tetramer Validation Initiative

Background Identification of T‐cell reactivity to β‐cell antigen epitopes is an important goal for studying pathogenesis and for designing and monitoring of immunotherapeutic interventions in type 1 diabetes (T1D). Methods We performed a multicentre validation of known human leukocyte antigen (HLA) class I CD8+ T‐cell epitopes. To this end, peripheral blood T‐cell responses were measured in 35 recently (<2 years) diagnosed HLA‐A*02:01+ T1D patients using blind‐coded HLA‐A2 tetramers (TMrs) and pentamers (PMrs), encompassing two epitopes of preproinsulin (PPI; PPI $\def\endash{\hbox{--}} _{\rm{A12\endash 20}}$ and PPI $\def\endash{\hbox{--}} _{\rm{B10\endash 18}}$ ) and two epitopes of glutamic acid decarboxylase (GAD; GAD 114–122 and GAD 536–545 ). We also compared the readout of TMrs and PMrs with a CD8+ T‐cell interferon‐γ enzyme‐linked immunospot assay. Results Despite the minute frequencies of autoreactive cells detected by TMrs/PMrs, most (73–77%) T1D patients had responses to one or more of the epitopes used. All four epitopes were recognized by T1D patients, with a prevalence ranging from 5 to 25%. TMrs and PMrs detected more positive responses to the β‐cell epitopes than CD8+ T‐cell interferon‐γ enzyme‐linked immunospot. However, concordance between positive responses to TMrs and PMrs was limited. Conclusions Using a multicentre blind‐coded setup and three different T‐cell assays, we have validated PPI and GAD epitopes as commonly recognized CD8+ T‐cell targets in recently diagnosed T1D patients. Both TMrs and PMrs showed higher detection sensitivity than the CD8+ T‐cell interferon‐γ enzyme‐linked immunospot assay. However, there are some important methodological issues that need to be addressed in using these sensitive techniques for detecting low frequency responses. Copyright © 2011 John Wiley & Sons, Ltd.