Abnormal response of cultured lymphocytes to phytohemagglutinin and autologous serum in cystic fibrosis.

Lymphocytes from adults homozygous or heterozygous for cystic fibrosis show biochemical abnormalities when cultured for 48 hours in the presence of phytohemagglutinin and autologous serum. In contrast to the 45 per cent increase in total protein and beta-glucuronidase concentrations seen in healthy control subjects when measured per 10(10) cells, both concentrations decreased by 1 per cent in adults heterozygous for cystic fibrosis and by 18 per cent in adults homozygous for cystic fibrosis. The abnormal response of the lymphocytes from persons with cystic fibrosis was due to a serum factor and not to any intrinsic abnormality of the lymphocytes. An abnormal response to hytohemagglutinin occurred in only 14 per cent of 44 healthy control subjects, but in 100 per cent of 14 adults homozygous for cystic fibrosis and in 85 per cent of 26 adults presumed to be heterozygous for cystic fibrosis. As a result of this phenomenon, lymphocytic beta-glucuronidase concentrations were significantly lower than normal in patients with cystic fibrosis when the cells were cultured with phytohemagglutinin and autologous serum. The demonstration of this phenomenon in both homozygotes and presumed heterozygotes (parents) suggests a relationship to the genetic defect in cystic fibrosis.