Effect of previous irradiation on the transformation of blood lymphocytes.

The transformation of blood lymphocytes in cultures with phytohaemagglutinin was studied in five patients before and at intervals up to 18 to 19 months after therapeutic irradiation of the abdomen and pelvis (dose of x rays 3,200r to 4,475r). In one patient, all cultures showed satisfactory lymphocyte transformation. In four patients transformation was depressed following irradiation. In three of these patients the duration of the depression was short; in one patient it was prolonged for over a year. The poor response of the lymphocytes to phytohaemagglutinin was not associated either with leucopenia or with a high incidence of cells with chromosome abnormalities in the cultures.