Endoscopic subureteral collagen injection: are immunological concerns justified?

Area of Science:

• Immunology
• Pediatric Urology

Background:

• Vesicoureteral reflux (VUR) is a common condition in children.
• Subureteral collagen injection is a minimally invasive treatment option for VUR.

Purpose of the Study:

• To evaluate the humoral immune response in children undergoing subureteral collagen injection for VUR.
• To analyze serum for the development of anticollagen antibodies post-treatment.

Main Methods:

• Serum samples were collected from 10 children (7 girls, 3 boys) before and after subureteral collagen injection.
• Antibody titers against bovine collagen and human collagen types I and III were measured using enzyme-linked immunosorbent assay (ELISA).
• Patients were monitored for adverse events indicative of an immune response.

Main Results:

• Three out of ten children developed antibodies to bovine collagen, with seroconversion occurring 13-24 months post-injection.
• One patient experienced bladder irritability after seroconversion, considered a potential local immunogenic reaction.
• No patients developed antibodies against human collagen types I or III, and no systemic autoimmune symptoms were observed.

Conclusions:

• Subureteral collagen injection for VUR can elicit a humoral immune response, specifically the development of antibodies to bovine collagen in a subset of patients.
• The volume of collagen injected did not appear to be a significant factor in immunogenicity.
• The treatment appears safe, with no evidence of systemic autoimmune disease development or cross-reactivity with human collagen.