Different immune cells at play in bone damage associated with septic arthritis
For thousands of different bacteria, the human body is their dream home. Take Staphylococcus aureus, a harmless tenant living on our skin until that is, it infects our joints, causing septic arthritis. In half of patients, this condition damages the bone to such an extent that they experience permanent joint dysfunction. Researchers investigate how this damage is caused by injecting the knees of mice with S. aureus lipoproteins (Lpps). A variety of immune cells infiltrated their joints: monocytes, macrophages and neutrophils. The team next depleted the mice of neutrophils and imaged their joints post-infection using micro-CT (pictured, middle), revealing greater bone damage compared to mice with a full complement of immune cells (left). In contrast, depleting the mice of macrophages and monocytes resulted in less bone damage (right), highlighting the opposing effects of different immune cells. Swaying the immune response in favour of neutrophils could prove useful in treating septic arthritis.
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