[en] The purpose of this study was to compare the effect of indium oxine and indium-tropolone complexes (nonradiolabeled) on the function of isolated human lymphocytes. Peripheral lymphocytes were obtained from 15 normal volunteers and incubated with indium oxine or indium tropolone according to the standard techniques currently used when cells are radiolabeled for subsequent in vivo studies. The phytohemagglutinin-induced (PHA) lymphocyte transformation and a more specific lymphocyte functional test (the mixed lymphocyte reaction) were performed following incubation with the indium complexes. The results indicate that PHA transformation is not affected by either indium oxine or indium tropolone, whereas both chelates reduced the mixed lymphocyte reaction. This suggests that these substances have a selective toxic effect only on a functionally distinct lymphocyte subset and indicates that there is no significant difference between the two indium chelates in terms of their effect on lymphocyte function

[en] Indium-111 oxine is currently used to label peripheral lymphocytes in order to study the kinetics of these cells in vivo. Since the quantity of radioisotope for labelling is still a matter of controversy, the authors have investigated in vitro the effect of increasing the concentration of indium-111 oxine on the lymphocyte surface phenotype and the antibody-dependent cellular cytotoxicity (ADCC) using lymphocytes from normal subjects. The cell surface phenotype, as evaluated by 2 monoclonal antibodies, was not affected whereas ADCC, at any of the doses used, was significantly reduced compared to the baseline value. The implications of these results for the use of indium-111 oxine for the in vivo studies are discussed. (Auth.)