Antibodies against alpha-fodrin in Sjögren's syndrome.

Alpha-fodrin is a part of the membrane skeleton and expressed in the majority of mammalian cells. It is cleaved in apoptosis by caspase 3. One of the cleavage products, a 120-kDa protein, represents a neoantigen. Antibodies against that cleavage product of alpha-fodrin have originally been described in a murine model of Sjögren's syndrome. In addition, they are also present in up to 93% of patients with Sjögren's syndrome, depending on the stringency of the classification used. Although antibodies against alpha-fodrin are observed in other diseases characterized by chronic apoptosis, they are a valuable laboratory marker in the evaluation of Sjögren's syndrome.