Regulatory T cells fail to suppress CD4+ T‐bet+ T cells in relapsing multiple sclerosis patients

Abstract

SummaryMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system and a defect in the regulatory T‐cell subset seems to be involved in the pathogenesis of the disease. Foxp3 is a transcription factor that is selectively expressed in CD4+ CD25+ regulatory T cells and is required for their development and function. T‐bet is a key transcription factor for the development of T helper 1 (Th1) cells. We found that both the percentage of circulating CD4+ CD25+ Foxp3+ cells and Foxp3 expression were lower in relapsing‐remitting (RR) MS patients during relapses than during remission. Otherwise, the percentage of CD4+ T‐bet+ T cells and T‐bet expression in CD4+ T cells were higher in relapsing than in remitting RRMS patients. CD4+ CD25+ T cells both from relapsing and from remitting RRMS patients showed significantly less capacity than corresponding cells from healthy subjects to suppress autologous CD4+ CD25− T‐cell proliferation, despite a similar Foxp3 expression level. CD4+ CD25+ T cells from healthy subjects and patients in remission clearly reduced T‐bet mean fluorescence intensity (MFI) in CD4+ CD25− T cells up to a ratio of 1:10, whereas CD4+ CD25+ T cells from patients in relapse were able to reduce T‐bet expression only at a high ratio. Our data indicate that the increased number of regulatory T (T‐reg) cells and the increased Foxp3 expression in circulating CD4+ CD25+ T cells may contribute to the maintenance of tolerance in the remission phase of MS. Moreover, the inhibitory capacity of CD4+ CD25+ T cells seems to be impaired in relapsing patients under inflammatory conditions, as shown by the high levels of T‐bet expression in CD4+ T cells.

Part of CIRS Nexus · Curated by Lauren Lowenstein, The Biotoxin Lady

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