Evaluation of antibody class in response to bovine collagen treatment in patients with urinary incontinence.

PURPOSE: Contigen Bard Collagen Implant (CI), made of highly purified bovine dermal type I collagen (BDC), is used as a bulking agent for the treatment of urinary stress incontinence. The humoral immune response to placement of this material in the urinary sphincter was evaluated.

MATERIALS AND METHODS: In a prospective clinical study, patients were treated with CI in the urinary sphincter, and blood was collected at various timepoints following injection. Approximately 28% of the patients treated with BDC demonstrated specific antibodies against bovine type I collagen. Serum samples from 27 patients from this cohort were evaluated. The class specificity of circulating antibodies against bovine collagen was characterized by an indirect enzyme-linked immunosorbent assay.

RESULTS: In all patients demonstrating an antibody response to bovine collagen, the predominant immunoglobulin class was IgG, found in 100% of sera samples. Immunoglobulin A was produced in approximately 40% of these patients, and IgM was seen in approximately 0.6%. No specific IgE was detected against bovine collagen in any serum sample. The highest concentrations of IgG and IgA antibody classes were observed 4 to 5 months after the initial treatment with CI. In the multicenter clinical trial, adverse events were reported in approximately 40% of all patients treated with CI (19). There was no correlation found between the production of a specific immunoglobulin class and the onset of any clinical adverse events.

CONCLUSIONS: In all sera from patients treated with CI for urinary stress incontinence, antibodies to bovine dermal collagen always were predominantly IgG. Immunoglobulin A was seen in less than half of the sera samples, and IgE was not observed. In addition, no change in the humoral response to CI over time was noted in patients demonstrating presensitization to bovine dermal collagen at the time of initial treatment. Clinical adverse events reported for patients demonstrating pretreatment antibodies against bovine dermal collagen did not differ in type or number when compared with patients having no presensitization.