Serum NCA in bone marrow transplant recipients and its metabolism

Normal colon and granulocyte antigen (NCA) in serum from 24 patients undergoing bone marrow transplantation (BMT), mostly for leukemic disease, was studied for a period of 0-60 days before/after transplantation. Out of the 23 patients with a take, 20 acquired elevated serum NCA. One patient had a rejection of the transplantation and never showed a rise of NCA values. Thirteen patients were studied in detail; 7 of them had an NCA rise 1-4 days before take, 4 at the day of take and 2 patients 1-4 days later. To investigate the rate of NCA turnover, 125I-NCA was injected into Macaca irus monkeys. One hour after injection, 87% of the injected substance had left the circulation. The prime site of accumulation was the liver. Thereafter, blood NCA decreased at a slower and linear rate. Of the substance seen at the beginning of the second phase 50% had been eliminated after 30 hours. The data support the theory that NCA is produced by the myeloid cells in bone marrow, that it has a rapid metabolism and therefore is of interest as a marker of bone marrow activity in health and malignant disease.