Paleopathologic evidence for the evolution of rheumatoid arthritis.

A human skeleton recovered from a Sicilian archaeological site and dating from the Hellenistic period (330-210 B.C.) presents a pathological pattern suggesting a transition between ankylosing spondylitis and rheumatoid arthritis, providing evidence in support of the hypothesis that rheumatoid arthritis may have recently evolved out of ankylosing spondylitis.