The Importance of Myeloid-Derived Suppressor Cells in Regulating Autoimmune Effector Cells in Chronic Contact Eczema

The study explored the role of myeloid-derived suppressor cells (MDSCs) in regulating autoimmune effector cells in the context of chronic contact eczema as a therapy for alopecia areata (AA). It was found that regulatory T cells were not responsible for hair regrowth, as transferring CD4+CD25high lymph node cells did not cure AA. Instead, Gr-1+CD11b+ cells, a type of MDSC, were significantly increased in the skin and spleen of AA mice treated with a contact sensitizer. These cells suppressed AA effector cell proliferation and promoted partial hair regrowth. They secreted high levels of nitric oxide when cocultured with CD4+ or CD8+ cells from AA mice, leading to down-regulation of ζ-chain expression and a decrease in ZAP70 and ERK1/2 phosphorylation, contributing to the silencing of autoreactive T cells.