How radiotherapy was historically used to treat pneumonia: could it be useful today?

Yale J Biol Med. 2013 Dec 13;86(4):555-70.


X-ray therapy was used to treat pneumonia during the first half of the 20th century. Fifteen studies report that approximately 700 cases of bacterial (lobar and bronchopneumonia), sulfanilamide non-responsive, interstitial, and atypical pneumonia were effectively treated by low doses of X-rays, leading to disease resolution, based on clinical symptoms, objective disease biomarkers, and mortality incidence. The capacity of the X-ray treatment to reduce mortality was similar to serum therapy and sulfonamide treatment during the same time period. Studies with four experimental animal models (i.e., mice, guinea pig, cat, and dog) with bacterial and viral pneumonia supported the clinical findings. The mechanism by which the X-ray treatment acts upon pneumonia involves the induction of an anti-inflammatory phenotype that leads to a rapid reversal of clinical symptoms, facilitating disease resolution. The capacity of low doses of X-rays to suppress inflammatory responses is a significant new concept with widespread biomedical and therapeutic applications.

Keywords: X-rays; anti-inflammation; hormesis; inflammation; pneumonia; radiotherapy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cats
  • Disease Models, Animal
  • Dogs
  • Dose-Response Relationship, Radiation
  • Guinea Pigs
  • Humans
  • Lung Diseases, Interstitial / drug therapy
  • Lung Diseases, Interstitial / radiotherapy*
  • Mice
  • Pneumonia, Bacterial / drug therapy
  • Pneumonia, Bacterial / radiotherapy*
  • Pneumonia, Viral / drug therapy
  • Pneumonia, Viral / radiotherapy*
  • Sulfonamides / therapeutic use
  • Survival Analysis
  • Treatment Outcome
  • X-Ray Therapy / methods*
  • X-Ray Therapy / trends


  • Sulfonamides