Multi-HLA class II tetramer analyses of citrulline-reactive T cells and early treatment response in rheumatoid arthritis.

Gerstner C, Turcinov S, Hensvold AH, Chemin K, Uchtenhagen H, Ramwadhdoebe TH, Dubnovitsky A, Kozhukh G, Rönnblom L, Kwok WW, Achour A, Catrina AI, van Baarsen LGM, Malmström V

BMC Immunol. 21 (1) 27 [2020-05-18; online 2020-05-18]

HLA class II tetramers can be used for ex vivo enumeration and phenotypic characterisation of antigen-specific CD4+ T cells. They are increasingly applied in settings like allergy, vaccination and autoimmune diseases. Rheumatoid arthritis (RA) is a chronic autoimmune disorder for which many autoantigens have been described. Using multi-parameter flow cytometry, we developed a multi-HLA class II tetramer approach to simultaneously study several antigen specificities in RA patient samples. We focused on previously described citrullinated HLA-DRB1*04:01-restricted T cell epitopes from α-enolase, fibrinogen-β, vimentin as well as cartilage intermediate layer protein (CILP). First, we examined inter-assay variability and the sensitivity of the assay in peripheral blood from healthy donors (n = 7). Next, we confirmed the robustness and sensitivity in a cohort of RA patients with repeat blood draws (n = 14). We then applied our method in two different settings. We assessed lymphoid tissue from seropositive arthralgia (n = 5) and early RA patients (n = 5) and could demonstrate autoreactive T cells in individuals at risk of developing RA. Lastly, we studied peripheral blood from early RA patients (n = 10) and found that the group of patients achieving minimum disease activity (DAS28 < 2.6) at 6 months follow-up displayed a decrease in the frequency of citrulline-specific T cells. Our study demonstrates the development of a sensitive tetramer panel allowing simultaneous characterisation of antigen-specific T cells in ex vivo patient samples including RA 'at risk' subjects. This multi-tetramer approach can be useful for longitudinal immune-monitoring in any disease with known HLA-restriction element and several candidate antigens.

PubMed 32423478

DOI 10.1186/s12865-020-00357-w

Crossref 10.1186/s12865-020-00357-w

pmc: PMC7236297
pii: 10.1186/s12865-020-00357-w