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Tuesday, January 31, 2006Mount Sinai School of Medicine researchers have identified the precursors of cells in the skin that are part of the first line of defense against invading pathogens. The study will appear on Nature Immunology's website this week and will be published in a future issue. A tight network of cells covering the entire body is formed in the skin by a group of cells known as Langerhans cells. These cells ingest antigens present in the skin and transport them to lymph nodes, activating the immune system to protect the body against pathogens. "Langerhans cells are particularly important to the development of tumor immunotherapy," said Miriam Merad, MD, PhD, Assistant Professor of Gene and Cell Medicine at Mount Sinai and lead author of the study. "Most vaccines being developed for tumors are injected into the skin and rely on these cells to transport the antigen to the lymph nodes to trigger an immune response against the tumor." Once Langerhans cells transport an antigen, they need to be replaced to maintain the tight network in the skin. Dr. Merad and colleagues at Mount Sinai School of Medicine recently discovered that when skin is inflamed Langerhans cells are replaced by circulating precursor cells. They have now identified what this precursor cell is and identified a protein that is essential to the transformation of these precursor cells into Langerhans cells. Last week, the FDA announced that two anti-eczema creams may increase the risk of skin cancer. Both drugs act by inhibiting the skin's immune system, though at the level of T-cells, rather than Langerhans cells - at least as far as the mechanism of action of the drugs is understood. They are believed to inhibit the production of chemicals which the skin's white blood cells use to communicate with one another. Since eczema is a condition in which the skin's immune system (and its white blood cells) is overactive, the approach makes since. However, the skin's immune system not only plays a role in fighting infection, it also helps destroy abnormal cells that can become cancer. It isn't too surprising, then, that there might be an increased risk of skin cancer in those who use these drugs. That's too bad, because the hope was that they would be better and for young children with eczema than potent topical steroids, which can cause problems with growth and development. posted by Sydney on 1/31/2006 08:10:00 AM 0 comments 0 Comments: |
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