Possible Source of Post-Lyme Complications Is Revealed

Even when promptly treated with appropriate antibiotics, some patients with Lyme disease have prolonged immunologically mediated complications such as arthritis. Given that the bacteria have almost surely been killed and that the residual antigens have been degraded, what prompts these lingering post-Lyme complications?

An international team reports that Borrelia burgdorferi has a peptidoglycan (PG^Bb) molecule in its cell envelope that is released but not degraded when the bacterium dies. PG^Bb lingers in synovial fluid and elicits an ongoing immune response (i.e., anti-PG^Bb immunoglobulins and proinflammatory cytokine production, particularly tumor necrosis factor α), even after antibiotic treatment. Immunoglobulins against PG^Bb also are fou…