MS Speaks

Nature Med. 2013 Dec 8. doi: 10.1038/nm.3411.

Regulatory T cell proliferative potential is impaired in human autoimmune disease

Carbone F, De Rosa V, Carrieri PB, Montella S, Bruzzese D, Porcellini A, Procaccini C, La Cava A, Matarese G.

1] Laboratorio di Immunologia, Istituto di Endocrinologia e Oncologia Sperimentale, Consiglio Nazionale delle Ricerche (IEOS-CNR), Napoli, Italy. [2] Dipartimento di Medicina e Chirurgia, Università di Salerno, Baronissi Campus, Baronissi, Salerno, Italy. [3].

Human CD4+CD25highCD127-FoxP3+ regulatory T (Treg) cells suppress immune responses in vitro and in vivo. Reduced suppressive function and/or number of peripheral Treg cells has been previously reported in autoimmune disorders. Treg cells represent the most actively replicating compartment within the CD4+ cells in vivo, but they are hyporesponsive to classical T cell receptor (TCR) stimulation in vitro, a condition that is secondary to their overactive metabolic state.

Here we report that proliferation of Treg cells after TCR stimulation is impaired in subjects with relapsing-remitting multiple sclerosis (RRMS) because of altered interleukin-2 (IL-2) secretion and IL-2 receptor (IL-2R)-signal transducer and activator of transcription 5 (STAT5) signaling. This is associated with decreased expression of the forkhead box P3 (FoxP3) 44- and 47-kDa splicing forms, overactivation of S6 ribosomal protein (a downstream target of the mammalian target of rapamycin, mTOR) and altered activity of the cyclin-dependent kinase inhibitor p27 (p27kip1) and extracellular signal-related kinases 1 and 2 (ERK1/2).

The impaired capacity of Treg cells to proliferate in RRMS correlates with the clinical state of the subject, where increasing disease severity is associated with a decline in Treg cell expansion. These results suggest a previously unrecognized mechanism that may account for the progressive loss of Treg cells in autoimmune disease.

PMID: 24317118