Preliminary report of an association between measles virus and achalasia.

Complement fixation tests were performed on sera from 18 patients with achalasia and 12 age- and sex-matched controls against a number of bacterial and viral agents in an attempt to ascertain any association with previous infection or any evidence of an altered immune response. There was a statistically significant increase of antibody titre against measles virus in the sera of 21 patients with achalasia compared with age- and sex-matched controls and this was confirmed by haemagglutination inhibition.