2. Relationship between immune activation, release of cytokines and formation of neopterin 2.1. Immunological and biological background of neopterin formation

Determinations of neopterin levels reflect the stage of activation of the cellular immune system which is of importance in the pathogenesis and progression of various diseases, e.g., in viral infections, in autoimmune or inflammatory diseases, rejection episodes following allograft transplantation and in several malignant diseases. Besides the importance of neopterin as a diagnostic marker new aspects point to a possible biological role of neopterin derivatives (hard copies of this monograph are available at www.brahms.de).