Pulmonary involvement starts in early stage ankylosing spondylitis.

@article{Baer2006PulmonaryIS,
  title={Pulmonary involvement starts in early stage ankylosing spondylitis.},
  author={Sevin Başer and Sibel Cubukcu and Sultan Ozkurt and Nuran Sabir and Beyza Akdağ and Erdal Diri},
  journal={Scandinavian journal of rheumatology},
  year={2006},
  volume={35 4},
  pages={325-7}
}