In the light of recent evidence, TLR4, transcription factors IRF 3 and 7, IL-8 and its receptors, PGE2, serum vitamin D and urinary antimicrobial peptides (NGAL, cathelicidin, HNP1-3 and SP-A) have been discerned as promising predictors of UTI recurrence. Here, LCN2 is linked to bacterial urinary tract infection.