Ninhydrin sweat test: A simple method for detecting antibodies neutralizing botulinum toxin type A

✍ Scribed by Bernhard Voller; Ekaterina Moraru; Eduard Auff; Michael Benesch; Werner Poewe; Jörg Wissel; Jörg Müller; Tanja Entner; Hans Bigalke; Peter Schnider

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 101 KB
• Volume: 19
• Category: Article
• ISSN: 0885-3185
• DOI: 10.1002/mds.20073

✦ Synopsis

Abstract

Approximately 5% of patients with cervical dystonia receiving repeated botulinum neurotoxin A (BoNT/A) injections develop secondary loss of treatment benefit. Currently available tests to directly detect neutralizing BoNT/A antibodies (BoNT/A‐AB) are either expensive or time consuming. To establish a simple, clinically useful test for antibody detection, we adapted the ninhydrin sweat test (NST). Eighteen dystonic patients with secondary nonresponse and clinically suspected BoNT/A‐AB formation were tested for BoNT/A‐AB in the mouse diaphragm test (MDT). In addition, the size of the anhidrotic area was determined by the NST 21 days after an intradermal dose of 10 U Dysport into the hypothenar region of the left palm. In nine patients, positive BoNT‐AB titers were found in the MDT. There was a significant correlation between the BoNT/A‐AB titers and the anhidrotic area (Spearman's rho = −0.9, P < 0.0001). Both tests provided comparably good results with respect to qualitative antibody detection. In the clinical situation of secondary nonresponse to BoNT/A therapy, the economical NST may be a helpful tool to detect neutralizing BoNT/A‐AB. © 2004 Movement Disorder Society