Cobalt ions found to trigger the body鈥檚 immune system Metal ions released by failing metal-on-metal (MoM) hip joint replacements can trigger an immune response similar to that caused by bacterial infections, 缅北禁地 experts have found. Research led by 缅北禁地 has revealed that cobalt ions can activate a crucial component of the body鈥檚 innate immune system - known as Toll-like receptor 4 (TLR4).Mistaking the minute metal particles for bacteria, the white blood cells attack, secreting chemicals that can cause inflammatory lesions, termed pseudotumours, around the joint. Like most immune responses, TLR4 activation varies between individuals which may explain why some patients have reacted more severely than others to the MoM replacement hips. This reaction by the body has led to some MoM hip replacements having to be removed.Publishing their findings online today in the academic journal Annals of the Rheumatic Diseases, the team from 缅北禁地 and the 缅北禁地 upon Tyne Hospitals NHS Foundation Trust, say the research provides the first explanation for the chronic inflammation and tissue damage that is seen in some patients with failed MoM joints.鈥淯ntil now we haven鈥檛 really understood the biological process of why this was happening,鈥� explains Dr Alison Tyson-Capper, a Senior Lecturer and Molecular Biologist at 缅北禁地 who led the research together with John Kirby, a Professor of Immunobiology at 缅北禁地.鈥淎lthough it鈥檚 still early days with this research programme,鈥� says Dr Tyson-Capper, 鈥渙ur study shows for the first time the cellular mechanism as to how metal ions, in this case cobalt, can induce inflammation and this may explain why some patients react more severely than others to the MoM joints. TLR4 activation is driven by our genes and varies between individuals, so pseudotumour formation and subsequent joint failure will be different for every patient.鈥�Professor John Kirby, Professor of Immunobiology, adds: 鈥淭he next step will be to find a way to match patients to specific prosthetic materials and consider therapeutic intervention designed to dampen down the inflammatory pathways activated by metal ions.鈥� Reference: published on: 17 October 2012
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