Non-specific cross-reacting antigen serum concentration in myeloid leukemias.

Non-specific cross-reacting antigen (NCA) was assayed radioimmunologically in normal sera and sera obtained from patients with chronic and acute myeloid leukemias. Normal value for NCA concentration was 37.8 ng/ml with a standard deviation of 14.6. In patients with chronic myeloid leukemia NCA serum concentration was significantly increased, and a study with regard to the stage of the disease (acute phase, blastic crisis, remission) was made. Individual cases were studied longitudinally. Patients with acute myeloid leukemias had a lower value than normal. The influence of chemotherapy on NCA serum concentration and the interest of NCA assay for follow-up of the patients are discussed.