New alopecia areata study findings have been reported by investigators at German Cancer Research Center
2007 NOV 12 -- New research, 'The importance of myeloid-derived suppressor cells in the regulation of autoimmune effector cells by a chronic contact eczema,' is the subject of a report. "Induction of a chronic eczema is a most efficient therapy for alopecia areata (AA). We had noted a reduction in regulatory T cells during AA induction and wondered whether regulatory T cells may become recruited or expanded during repeated skin sensitization or whether additional regulatory cells account for hair regrowth," scientists in Heidelberg, Germany report. "AA could not be cured by the transfer of CD4(+)CD25(high) lymph node cells from mice repeatedly treated with a contact sensitizer. This obviously is a consequence of a dominance of freshly activated cells as compared with regulatory CD4(+)CD25(+) T cells. Instead, a population of Gr-1(+)CD11b(+) cells was significantly increased in skin and spleen of AA mice repeatedly treated with a contact sensitizer. Gr-1(+)CD11b(+) spleen cells mostly expressed CD31. Expression of several proinflammatory cytokines as well as of the IFN-gamma receptor and the TNF receptor I were increased. Particularly in the skin, Gr-1(+) cells expressed several chemokines and CCR8 at high levels. Gr-1(+)CD11b(+) cells most potently suppressed AA effector cell proliferation in vitro and promoted partial hair regrowth in vivo. When cocultured with CD4(+) or CD8(+) cells from AA mice, the Gr-1(+)CD11b(+) cells secreted high levels of NO. However, possibly due to high level Bcl-2 protein expression in AA T cells, apoptosis induction remained unaltered. Instead, zeta-chain expression was strongly down-regulated, which was accompanied by a decrease in ZAP70 and ERK1/2 phosphorylation," wrote R. Marhaba and colleagues, German Cancer Research Center. The researchers concluded: "Thus, a chronic eczema supports the expansion and activation of myeloid suppressor cells that, via zeta-chain down-regulation, contribute to autoreactive T cell silencing in vitro and in vivo." Marhaba and colleagues published their study in the Journal of Immunology (The importance of myeloid-derived suppressor cells in the regulation of autoimmune effector cells by a chronic contact eczema. Journal of Immunology, 2007;179(8):5071-81). For more information, contact R. Marhaba, German Cancer Research Center, Dept. of Tumor Progression and Immune Defense, Heidelberg, Germany. Publisher contact information for the Journal of Immunology is: American Association Immunologists, 9650 Rockville Pike, Bethesda, MD 20814, USA. Keywords: Germany, Heidelberg, Alopecia Areata, Autoimmune Disease, Autoimmune Disorder, Cancer Research, Dermatology, Eczema, Immunology, Rheumatology, Therapy, Treatment. This article was prepared by Biotech Business Week editors from staff and other reports. Copyright 2007, Biotech Business Week via NewsRx.com.
|
