The immunological basis for treatment of stiff person syndrome.

Antibodies against autoantigens involved in GABAergic neurotransmission are a shared feature of the different subtypes of stiff person syndrome (SPS). The autoantigens can be either presynaptic such as the smaller isoform of glutamic acid decarboxylase (GAD65), postsynaptic such as GABA-A receptor-associated protein and gephyrin, or located at the pre- and postsynaptic side such as amphiphysin. Most of these autoantigens are intracellular, and antibodies against GAD65 also occur in diabetes mellitus type 1 as well as other neurological diseases. Their pathogenic role has therefore been questioned. We here discuss the role of autoantibodies and T cells in SPS.