The effect of radial radiotherapy on delayed hypersensitivity and the inflammatory response.

Delayed hypersensitivity to DNCB and the inflammatory response to croton oil wereevaluated in 144 and 121 patients respectively, prior ro and 3 to 6 months following curative radiotherapy. Eighty-one patients had in vitri lymphocyte transformation by PHA;59 (41%) were nonreactors to DNCB and 27 (22%) to croton oil; 29 of 59 (49%) initiallyreactive became anergic. Similiar improvement of the inflammatory response was obtained. Patients who became DNCB-reactive following radiotherapy had the same favorable prognosis as those who were initially reactive. Radiotherapy did not adversely affect either delayed hypersensitivity or the inflammatory response. There was a 50% decrease in PHA stimulation and lymphocyte count after treatment. No correlation was found between DNCB reactivity and lymphocyte transfermation prior to or following radiotherapy. The evaluation of the effect of radiotherapy on cell-mediated immunity depends on the tests used.