While being neglected for decades, tumor immune escape is now considered as a new paradigm that promotes tumor growth and evasion. Besides the prototypical PD1 / PDL1 axis, several mechanisms have been identified as important actors in immune editing process. Indoleamine 2,3 dioxygenase (IDO1), a first rate-limiting enzyme of the Kynurenine pathway, has been described to favor tolerance and immune escape through the production of a series of metabolites, including L-Kynurenine. In this context, our ISE-2227 Kynurenine/tryptophan ELISA pack represents a powerfull tool to adress these metabolites.

Assessment of plasmatic kynurenine/tryptophan levels in cancer patients. A cohort of patients with various types of sarcomas were treated with immunotherapy (Pembrolizumab) and plasma were collected before (at cycle 1, day 8)  and after (at cycle 2, day 8) the first infusion of pembrolizumab. Kynurenine and tryptophan plasma levels were measured by mean of ELISA (ISE-2227 Kynurenine/tryptophan IVD ELISA pack). A statistically significant increase in the kynurenine to tryptophan plasma ratio in patients during treatment was reported, underlying the role of the IDO1/kynurenine pathway in the resistance to PD-1/PD-L1 targeting in sarcomas (from Toulmonde et al., JAMA Oncology, Jan 2018).