Apoptotic Effects of Antilymphocyte Globulins on Human Pro-inflammatory CD4.sup.+CD28.sup.- T-cells

Pro-inflammatory, cytotoxic CD4.sup.+ CD28.sup.- T-cells with known defects in apoptosis have been investigated as markers of premature immuno-senescence in various immune-mediated diseases. In this study we evaluated the influence of polyclonal antilymphocyte globulins (ATG-Fresenius, ATG-F) on CD4.sup.+ CD28.sup.- T-cells in vivo and in vitro. In summary, in vivo depletion of peripheral CD3.sup.+ CD4.sup.+ CD28.sup.- T-cells by ATG-F in transplant recipients was paralleled in vitro by ATG-F induced apoptosis. CD25 expression and chemokine receptor down-regulation in CD4.sup.+ CD28.sup.- T-cells only partly explain the underlying mechanism.