Immune Expression in Children With Vesicoureteral Reflux: A Pilot Study.

OBJECTIVE: To perform an exploratory, descriptive pilot study of the systemic and local immune environment in patients with vesicoureteral reflux (VUR) and bladder-bowel dysfunction (BBD). METHODS: Consecutive children with VUR undergoing intravesical ureteral reimplantation were enrolled. Patients were assessed for presence of BBD by reported patient history and validated questionnaire. Fresh blood and bladder tissue, collected at the time of surgery, were immediately processed for analysis. Immune cell compositions were determined via flow cytometry. Immune cell activation was also defined at the time of analysis. LegendPlex assay analysis was utilized to define levels of circulating chemokines and cytokines. RESULTS: A total of 7 patients were enrolled. Although percentages of circulating immune cells in the blood of those with VUR/BBD and VUR alone were similar, within bladder tissue, VUR/BBD demonstrated increased immune infiltrates compared to VUR alone. Bladder sample analysis showed that B cells, and Effector Memory and Naïve T cell percentages were significantly increased in VUR/BBD patients compared to VUR patients. T cell expression of PD1 was increased in bladder tissues of BBD/VUR. Additionally, analysis of circulating neutrophils displayed significantly increased upregulation of PDL-1 in patients with VUR/BBD vs those with VUR only. CONCLUSION: These pilot data suggest an immune-rich microenvironment is present within VUR. Severity of inflammation appeared to correlate with presence of BBD. This implies that targeting pelvic inflammation may be a novel therapy for children with VUR- or non-VUR-related BBD. Follow-up studies are currently underway.