Surface expression of CD39 identifies an enriched Treg-cell subset in the rheumatic joint, which does not suppress IL-17A secretion.

European journal of immunology

PubMedID: 24990235

Herrath J, Chemin K, Albrecht I, Catrina AI, Malmström V. Surface expression of CD39 identifies an enriched Treg-cell subset in the rheumatic joint, which does not suppress IL-17A secretion. Eur J Immunol. 2014;.
Regulatory T (Treg) cells are important for the maintenance of self-tolerance and are implicated in autoimmunity. Despite enrichment of Treg cells in joints of rheumatoid arthritis (RA) patients, local inflammation persists. As expression of the ATP-hydrolyzing enzymes CD39 and CD73 and the resulting anti-inflammatory adenosine production have been implicated as an important mechanism of suppression, we characterized FOXP3(+) Treg cells in blood and synovial fluid samples of RA patients in the context of CD39 and CD73 expression. Synovial FOXP3(+) Treg cells displayed high expression levels of rate-limiting CD39, whereas CD73 was diminished. FOXP3(+) CD39(+) Treg cells were also abundant in synovial tissue. Furthermore, FOXP3(+) CD39(+) Treg cells did not secrete the pro-inflammatory cytokines IFN-? and TNF after in vitro stimulation in contrast to FOXP3(+) CD39(-) T cells. FOXP3(+) CD39(+) Treg cells could be isolated by CD39 and CD25 co-expression, displayed a demethylated TSDR and co-culture assays confirmed that CD25(+) CD39(+) T cells have suppressive capacity, while their CD39(-) counterparts do not. Overall, our data show that FOXP3(+) CD39(+) Treg cells are enriched at the site of inflammation, do not produce pro-inflammatory cytokines and are good suppressors of many effector T-cell functions including production of IFN-?, TNF and IL-17F but do not limit IL-17A secretion. This article is protected by copyright. All rights reserved.