title: [Elevation of soluble transferrin receptor substance in serum of cancer patients with suppressed natural killer activity].
abstract: Soluble transferrin receptor (sTfR) in serum of cancer patients was measured by a sandwich enzyme-linked immunosorbent assay, and the effect of sTfR for natural killer cytotoxicity was also studied. The statistical values of sTfR levels in sera were found to be 250 +/- 77 U (Mean +/- SD) in healthy individuals, while 288 +/- 162 U in chronic liver disease, 402 +/- 290 U in hepatocellular carcinoma, 429 +/- 261 U in gastric cancer, 347 +/- 207 U in acute leukemia and malignant lymphoma, and 251 +/- 100 U in other cancer. No significant difference in the sTfR levels among the patients was observed, although the difference between the healthy individuals and the patient groups was shown to be statistically significant at p less than 0.01 level. The effect of sTfR isolated from serum of a patient with iron-deficiency anemia by means of Sephadex G-200 column for natural killer activity was carried out. Cytotoxicity of natural killer cell in healthy individuals was inhibited by sTfR as the dose dependent manner, and the inhibitory rate was found to be 23.1 +/- 12.8% (Mean +/- SD) when the concentration of the sTfR was 1,250 U added in the cytotoxicity test. Furthermore, the inhibitory activity of serum in cancer patients was correlated with the sTfR level. These results suggest that sTfR is one of the inhibitory factors for the natural killer cell activity in vivo, and the factor could be facilitated for tumor growth and metastasis. Therefore, the measurement of sTfR in serum may be useful for monitoring immunological competency in cancer patients.
authors.forename: K
authors.initials: K
authors.lastname: Yoshimoto
mesh_terms: D000747:Anemia, Hypochromic / Q000097:blood; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D009369:Neoplasms / Q000097:blood* / Q000276:immunology; D011990:Receptors, Transferrin / Q000032:analysis* / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D011990:Receptors, Transferrin