Botulinum toxin antibody testing: comparison between the mouse protection assay and the mouse lethality assay.
Conventionally, the standard test for detection of antibodies against botulinum toxin (BT-A) has been the mouse lethality assay (MLA). Because this test has a number of disadvantages, a novel mouse protection assay (MPA) was recently introduced. We sought to compare the results of both tests. Forty-three samples from 38 patients with cervical dystonia and complete or partial subjective BT-A therapy failure underwent simultaneous MPA and MLA testing. Twenty-seven samples showed concordant results in both tests. Eleven of them were MPA- and MLA-positive and 16 MPA- and MLA-negative, resulting in a significant association of the dichotomous test results (Fisher exact test, p <0.01). Sixteen samples showed discordant results. All of those were MPA-positive and MLA-negative. This excess of MPA-positive results was also significant (Wilcoxon signed-rank test, p <0.001). Of the patients with MPA-positive samples, 62% had complete and 38% had partial therapy failure. Of the patients with MLA-positive samples, 90% had complete and 10% had partial therapy failure. MPA and MLA results show significant association. Statistical analysis and predominance of partial therapy failure in MPA-positive patients demonstrate higher sensitivity of MPA. With its methodologic advantages, its test parameter being more relevant to BT-A therapy, and its higher sensitivity, the MPA appears to be superior to the MLA.
Dressler
D
D
Institute of Neurology, London, UK.
Dirnberger
G
G
Bhatia
K P
KP
Irmer
A
A
Quinn
N P
NP
Bigalke
H
H
Marsden
C D
CD
D000818:Animals; D018726:Anti-Dyskinesia Agents / Q000276:immunology* / Q000494:pharmacology / Q000627:therapeutic use; D000907:Antibodies, Bacterial / Q000097:blood*; D000917:Antibody Formation; D001681:Biological Assay / Q000379:methods*; D019274:Botulinum Toxins, Type A / Q000276:immunology* / Q000494:pharmacology / Q000627:therapeutic use; D004351:Drug Resistance; D020821:Dystonic Disorders / Q000188:drug therapy* / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D017211:Treatment Failure
D018726:Anti-Dyskinesia Agents; D000907:Antibodies, Bacterial; D019274:Botulinum Toxins, Type A