Abstract: There is provided a use of a modulator of Notch signalling for the preparation of a medicament for treatment of Graft Versus Host Disease (GVHD) and diseases and conditions caused by or associated with transplants such as organ, tissue and/or cell transplants (e.g. bone marrow transplants), wherein the modulator is used to reduce the reactivity of cells of the immune system.

Abstract: The present invention relates to the use of therapeutic compounds in the modification of T-cell, T-cell antigen presenting cell (APC) interactions and the interactions between pathogenic organisms and immunocompetent cells of a host. In particular it relates to the use of these compounds in the modulation of the interaction between Notch proteins and their ligand and to the use of such compounds in the therapy of conditions such as graft rejection, autoimmunity, allergy, and asthma and infectious diseases.