Il-7rα low memory cd8 + t cells are significantly elevated in patients with systemic lupus erythematosus

Abstract

Objective. Human effector memory (EM) CD8 + T cells include IL-7Rα high and IL-7Rα low cells with distinct cellular characteristics, including the expression of cytotoxic molecules. Both NK cells and the NK cell-associated molecule 2B4 that is expressed on CD8 + T cells promote cytotoxicity. Here we analysed the expression of 2B4 on IL-7Rα high and IL-7Rα low EM CD8 + T cells and its contribution to cytotoxicity. We also analysed the frequency of IL-7Rα high and IL-7Rα low EM CD8 + T cells in patients with SLE or lupus and in healthy individuals given the potential role of cytotoxic CD8 + T cells in the pathogenesis of lupus.Methods. We used flow cytometry to measure the expression of 2B4 on IL-7Rα high and IL-7Rα low EM CD8 + T cells as well as the frequency of these cell populations in the peripheral blood of healthy individuals and patients with SLE. Also, 2B4-mediated cytotoxicity was quantitated in IL-7Rα high and IL-7Rα low EM CD8 + T cells using target cells with CD48 antigen.Results. We found that IL-7Rα high EM CD8 + T cells had higher levels of 2B4 expression compared with IL-7Rα low EM CD8 + T cells. Triggering 2B4 enhanced the cytotoxic function of IL-7Rα low EM CD8 + T cells against target cells. We also noticed that patients with SLE had an increased frequency of IL-7Rα low EM CD8 + T cells that correlated with disease manifestation.Conclusion. Our findings show that SLE patients have increased IL-7Rα low EM CD8 + T cells, possibly contributing to tissue damage through 2B4-mediated cytotoxicity. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.