Are there immunologically treatable motor neuron diseases?

Several studies have addressed the issue of a possible immunological involvement in the pathogenesis of amyotrophic lateral sclerosis (ALS) or motor neuron disease (MND), particularly when the disease was associated with cancer, lymphoma or other monoclonal gammopathies or with the presence of serum antibodies to neural antigens. The hypothesis of the existence of immunologically treatable MND was reinforced by the occasional report of MND patients responding to immune or cytostatic therapies and by the identification among those with a purely lower motor neuron syndrome (LMNS) of a motor neuropathy, presently known as multifocal motor neuropathy (MMN), which almost invariably responded to immune therapies. These observations have led to several attempts to treat patients with MND or LMNS, either idiopathic or associated with the above mentioned conditions, with a number of immune or cytostatic therapies. The aim of this review is to verify whether the available data provide enough evidence to support the concept of dysimmune MND and to justify the use in these patients of potentially harmful immune cytostatic therapies.