Antibody formation following botulinum toxin type A (Dysport) injection in children with intractable bladder hyper-reflexia.

OBJECTIVES

To investigate the pattern of anti-Dysport antibody (ADA) formation after Dysport injection in patients with neuropathic bladder. Antibody formation may lead to failure or allergic reactions in patients undergoing Dysport injection.

METHODS

Forty-four children with neuropathic bladder were enrolled and classified into 3 groups: group I, without history of previous injection (n = 8); group II, with history of one or more injections (n = 7); and group III, who had been injected 3-36 months before this study (n = 29). Groups I and II were subjected to Dysport injection. Fifty-five age-matched healthy children were selected as controls. Urinary incontinence score was assessed before and 6 months after injection. Under cystoscopic guidance, Dysport (10 IU/kg) was injected into the detrusor muscle, sparing the trigone and ureteral orifices. ADA level was measured by enzyme-linked immunosorbent assay technique before injection and then monthly for at least 4 months in groups I and II, and for just once in group III and control subjects.

RESULTS

ADA level was increased 1-2 months after the last injection in 3 (38%) of group I and 5 (71%) of group II. However, ADA level in group III was not higher than controls. All patients had complete or partial improvement in urinary incontinence score except for 1 patient in group I. No resistance to treatment was detected.

CONCLUSIONS

Increment of ADA titer in patients is not permanent. Repeated injections will not boost the immune system to produce higher levels of antibody. Increased levels of ADA may not be associated with treatment failure at follow-up visit.