Identificación y utilidad clínica de los anticuerpos antineuronales

We review the neuronal antibodies described in CNS disorders in order to clarify their diagnostic value. In this work, the neuronal antibodies associated with syndromes resulting from CNS neuronal dysfunction were classified into two groups according to the location of the antigen inside the neuron or in the cell membrane. Group I includes antibodies that target intracellular antigens and are probably not pathogenic. They include onconeural antibodies (Hu [ANNA1], Yo [PCA1], Ri [ANNA2], CV2 [CRMP5], amphiphysin, Ma2, Tr, SOX1), which are useful for the diagnosis of paraneoplastic neurological syndromes (PNS). Other antibodies of this group, mainly anti-glutamic acid decarboxylase (GAD) antibodies, identify non-paraneoplastic syndromes (PNS), such as stiff-person syndrome (SPS), cerebellar ataxia, and limbic encephalitis (LE). Group II antibodies recognize neuronal surface antigens. Antibodies in this group are associated with characteristic CNS syndromes, but their detection does not indicate that the disorder is paraneoplastic. The most frequent are the anti-receptor NMDA antibodies, followed by the antibodies against the protein LGI1 associated with the potassium channel. Other less common antibodies include those against the receptors of AMPA, GABAb, mGluR 1 and 5, and against CASPR2. A pathogenic role of the antibodies is suggested by the response of symptoms to immunotherapy, and the correlation between antibody titers and neurological outcome.