Selective suppression of cerebellar GABAergic transmission by an autoantibody to glutamic acid decarboxylase.

Humoral immune response to glutamic acid decarboxylase (GAD) has been implicated in the pathogenesis of stiff-man syndrome and cerebellar ataxia, but the underlying pathomechanism is unclear. Using a whole-cell patch-clamp technique with rat cerebellar slices, we found that immunoglobulins present in the cerebrospinal fluid of an ataxic patient acted presynaptically to cause a selective suppression of GABAergic transmission. This synaptic depression was most likely elicited by an autoantibody to GAD.