Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Background/Purpose: Tissue resident memory T (TRM) cells survive indefinitely in barrier tissues and mediate swift immunologic memory responses at sites of microbe entry. TRM cells have been implicated in recurrent site-specific inflammation in skin, intestine, and lung, but little is known about TRM cells in synovium. We employed a highly efficient 3-dimensional (3-D) explant culture technique, developed to recover TRM from skin, to investigate synovial infiltrating T cells.
Methods: Subjects with rheumatoid arthritis (RA) were identified by International Classification of Disease (ICD) codes, supported by medical record review by a board-certified rheumatologist. Synovial tissue samples were obtained from RA patients undergoing medically necessary joint surgery. Collagenase digestion and/or 3-D explant culture was used to isolate synovial T cells. In the 3-D explant culture system, 2mm x 2mm pieces of synovial tissue were placed on Cellfoam matrices, and cultured in T cell media enriched with IL-2 and IL-15 for 3 weeks. Multidimensional analysis of surface markers and cytokine production upon stimulation was performed by mass cytometry (CyTOF).
Results: Synovial samples were obtained from 13 women and 2 men with established RA. Treatment regimens varied (methotrexate, n=9; tumor necrosis factor inhibitors, n=6; prednisone, n=5; non-steroidal anti-inflammatory drugs, n=5). 3-D explant culture of RA synovium samples yielded 5-fold more mononuclear cells, on average, than collagenase digestion (mean number mononuclear cells per mg tissue ± SEM: 25,000 ± 17,000 vs. 5,600 ± 4,700). Approximately, 80% of cells collected by the 3-D explant culture method were CD3+ T cells, with the majority being CD4+ T cells (~80%). The ratio of CD4+ to CD8+ cells was not significantly different between the recovery methods. Multidimensional mass cytometry analyses demonstrated dramatic differences in phenotype between synovial and blood CD4+ memory T cells, with significantly increased CD49d and MHCII and decreased CD27 on synovial T cells. A Th1 phenotype predominated in synovial T cells isolated by explant cultures, with ~35% of CD4+ memory T cells expressing IFNγ and Tbet upon stimulation. Notably, memory CD4+ T cells with a phenotype consistent with TRM cells (CD62L–, CCR7–, CD69+) were identified in all tested synovial samples. While CD69 expression may be induced by recent activation, many of these potential TRM (CD62L–, CCR7–, CD69+) cells did not express two other markers of recent activation, CD25 and MHCII.
Conclusion: 3-D explant culture is a novel tool that can be employed to study lymphocytes that are resident in synovium. Memory T cells with TRM features were identified in synovial samples from RA patients, supporting the hypothesis that this T cell subset may contribute to the persistence and recurrence of inflammatory arthritis. Further study will be needed to define the functional characteristics and pathophysiologic role of these cells.
To cite this abstract in AMA style:Henderson L, Rao D, Teslovich N, King S, Mizoguchi F, Ameri S, Morris A, Elco C, Lederer J, Martin S, Simmons B, Wright J, Brenner M, Raychaudhuri S, Nigrovic P, Fuhlbrigge R. 3-D Explant Method Facilitates the Study of Lymphocytes in Synovium and Reveals a Population of Resident Memory-like T Cells in Rheumatoid Arthritis [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/3-d-explant-method-facilitates-the-study-of-lymphocytes-in-synovium-and-reveals-a-population-of-resident-memory-like-t-cells-in-rheumatoid-arthritis/. Accessed March 4, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/3-d-explant-method-facilitates-the-study-of-lymphocytes-in-synovium-and-reveals-a-population-of-resident-memory-like-t-cells-in-rheumatoid-arthritis/