α-Fodrin autoantibodies in the differential diagnosis of MS and Sjogren syndrome

It is often difficult to diagnose Sjogren syndrome (SS) with neurologic manifestations as frequently only the nervous system is affected and anti-Ro (SSA) and anti-La (SSB) antibodies are found in fewer than 50% of cases.1,2⇓ In a recent study, we demonstrated that primary progressive multiple sclerosis (PPMS) should be the principal differential diagnosis for SS with CNS manifestations.2 However, the question remains as to whether SS is secondary to MS or whether the two are separate entities.3,4⇓ It was recently reported that antibodies against α-fodrin are both a sensitive and a specific marker for SS.5,6⇓ α-Fodrin is a cytoskeletal protein that binds to the cytoplasmic domains of a variety of molecules expressed on the cell surface. It is abundantly expressed in salivary glands but also other tissues including synapses and is probably involved in exocytosis. α-Fodrin is cleaved by caspase 3 upon apoptosis into …