Although the diagnosis of interstitial cystitis and bladder pain syndrome (IC/BPS) should be made after ruling out bacterial cystitis, microorganism infection in the bladder still has been considered as a possible etiology of IC/BPS. Early viral studies of IC/BPS revealed conflicting results due to small case number. The aim of current study is using polymerase chain reaction (PCR) to investigate different kinds of virus load in the urine of patients with IC/BPS.

From 2017 to 2018, IC/BPS patients who were admitted to our hospital for hydrodistention were prospectively enrolled into this study. Before the hydrodistention (under general anesthesia), urine from patients with IC/BPS was collected via urethral catheterization after the standard aseptic procedures. The patients with stress urinary incontinence in outpatient clinic were also asked to collect urine. The midstream urine specimens were taken and were considered as control subjects. Using PCR, the urine samples were investigated for virus DNA including adenovirus (139-bp region of the hexon gene), bocavirus (NP-1 gene), BK virus (UCL-F1 gene) and herpes viruses (HSV, multiplex PCR, including HSV-1, HSV-2, Epstein–Barr virus, cytomegalovirus and varicella-zoster virus).

A total of 54 IC/BPS patients (56.6±12.4 years old) and 51 control subjects (66.8±12.2 years old) urine samples were investigated by virus DNA PCR. The urine bocavirus was detected in 11 (20.4%) IC/BPS patients and 6 (11.8%) control subjects (p=0.233). The urine adenovirus was detected in 6 (12%) IC/BPS and 12 (23.5%) control subjects (p=0.132). All urine samples, including control and IC/BPS patients, were negative for HSV and BK virus. The clinical parameters between IC/BPS patients with positive or negative urinary virus do not have significant difference (Table 1). Among the 8 IC/BPS patients with Hunner’s lesion, 2 of them were positive for urinary bocavirus, and only one was positive for urinary adenovirus.

Current study might be the largest series to investigate urinary virus load in patients with IC/BPS. Our data revealed using PCR could detect urinary bocaviorus and adenovirus DNA in IC/BPS patients and control subjects. However, HSV and BK virus could not be detected in our PCR study. Virus infection as a possible etiology of IC/BPS had been a long-standing debatable issue. Our study does not show significant association between urinary virus load and IC/BPS. Further investigations using different PCR primers or in situ hybridization to detect virus presence in IC/BPS bladders are necessary to explore the role of virus in the pathogenesis of IC/BPS.

Our large IC/BPS patient series does not showed significant association between urinary virus load and IC/BPS. Further investigations using different PCR primers to detect virus presence in IC/BPS are necessary to explore the role of virus in IC/BPS.