[Clinical relevance of botulinum toxin antibodies]

Botulinum toxin antibodies (BT-AB) can be neutralising and non-neutralising, their titres therapy-relevant and non-therapy-relevant. Botulinum toxin (BT) and BT-AB form a functional balance, thus explaining partial and complete therapy failure. Antibody-induced BT therapy failure (ATF) is rare. Clinically it tends to follow a three-phase reaction. Complete ATF occurs in a typical time window. Risk factors for ATF are the amount of BT given at each injection series, duration of the interval between injections, quality of the BT preparation, and individual particularities of the patient's immune system. The detection of BT-AB is complicated. It always needs interpretation and is of major importance for the further treatment strategy.