CYTOKINES AND THE TH1 TH2 PARADIGM IN TRANSPLANTATION/

With studies elucidating the cytokine programs associated with T-cell activation, allograft rejection and tolerance induction, the Th1/Th2 p aradigm has became a unifying model to explain the observed cytokine p rofiles. The proof that these cytokines mediate allograft tolerance, h owever, is at best indirect. More recent studies highlighting the redu ndant and pleiotropic nature of cytokine networks suggest that the Th1 /Th2 paradigm may not be sufficient to explain fully the mechanisms un derlying allograft tolerance.