TPH1 and hydronephrosis: Notably, multivariate analysis identified five independent risk factors for post-PCNL SIRS: high stone density (odds ratio [OR], 5.96; p < 0.001), prolonged operation time (OR, 2.26; p = 0.005), absence of hydronephrosis (OR, 0.37; p < 0.001), positive urine detection for bacteria (OR, 2.13; p = 0.003) and low percentage of circulating Tph cells (OR, 0.39; p < 0.001).