Expression of programmed death ligand-1 on bladder tissues is detected in a clinically and histologically well-defined interstitial cystitis cohort

Objective: To investigate the expression of programmed death ligand-1 (PD-L1) in interstitial cystitis (IC). Methods: We reviewed the data of IC patients underwent hydrodistension plus bladder biopsy. Follow-ups were performed. We assessed the degree of inflammation of the bladder wall on slides stained with hematoxylin and eosin (H&E). We performed immunohistochemistry for PD-L1 expression detection and for counting T lymphocytes and B lymphocytes. Results: The present study included eight men and 32 women. With H&E staining, we detected 13, 15, and 12 patients with mild, moderate, and severe inflammation. The degree of inflammation was negatively correlated with disease course (P = 0.018) and positively correlated with bladder pain (P < 0.001). Hydrodistension was found effective at postoperative 3-month for 19 patients. Overall, 17, 15, 7, and 1 subject had no, mild, moderate, and high PD-L1 expression, that correlated positively with the degree of inflammation. Compared with patients with no and mild PD-L1 expression, patients with moderate and high PD-L1 expression tended to have more effective hydrodistension outcomes (12 of 32 vs 7 of 8; P = 0.017). In the subset of 12 patients with severe inflammation, there were five of six patients (83.3%) with moderate or high PD-L1 expression and one of six patients (16.7%) with no and mild PD-L1 expression with an effective hydrodistension outcome. Conclusions: Expression of PD-L1 on bladder is detected in a cohort of IC patients presented with diffuse global glomerulation or Hunner ulcer. PD-L1 expression is more common in IC patients with severe bladder inflammation.