This is in agreement with a previous study [15] demonstrating that activation of iNOS expression in A498 cells depends on cytokines such as IL-1?? and IFN-?? while UPEC per se are weak inducers of iNOS in vitro.Neutrophils and renal epithelial cells express the iNOS enzyme in different UTI-models, which suggests that these cell types are able to produce NO during UTI [4,5,7,8].