The following is a summary of “Technical Validation and Utility of an HLA Class II Tetramer Assay for Type 1 Diabetes: A Multicenter Study,” published in the January 2024 issue of Endocrinology by Ettinger, et al.

There was a demand for validated assays capable of measuring autoantigen-specific T-cell frequency and phenotypes to evaluate the risk, progression, and treatment responses of diabetes, particularly type 1 diabetes (T1D). For a study, researchers sought to technically validate a tetramer assay targeting HLA-DRA-DRB1*04:01, a class II allele strongly linked to T1D susceptibility.

Using a tetramer assay, they quantified and characterized HLA-DRA-DRB1*04:01-restricted T cells responding to immunodominant epitopes from islet cell antigens GAD65, IGRP, preproinsulin, and ZnT8, alongside a reference influenza epitope. The assay underwent single and multicenter testing, including clone-spiked specimens and replicate samples from T1D patients, aiming for a coefficient of variation (CV) <30%. Additionally, we applied the assay to an exploratory cross-sectional sample set of 24 T1D patients to assess its utility.

In single-center testing, influenza-specific T-cell measurements achieved mean CVs of 6% (clone-spiked specimen) and 11% (T1D samples), while multicenter testing yielded mean CVs of 20% and 31%, respectively. Islet-specific T-cell measurements showed mean CVs of 14% and 23% (single-center) and 23% and 41% (multicenter). The cross-sectional study revealed associations between T-cell frequencies and phenotypes with disease duration, sex, and autoantibodies. Notably, a substantial portion of islet-specific T cells exhibited a naive phenotype.

The findings indicated that the assay is reproducible and valuable for characterizing islet-specific T cells, enabling the identification of correlations between T-cell measures and clinical traits in T1D patients.

Reference: academic.oup.com/jcem/article/109/1/183/7227279