OBJECTIVE To identify new autoantigens related to Sjögren's syndrome and to determine their prevalence in patients and healthy individuals. MATERIAL AND METHODS Serological sampling was performed in a patient with Sjögren's syndrome through the use of a human brain expression genotec (SEREX technique) to determine expression of known autoantigens and previously undescribed proteins. The presence of a previously unknown protein was found. Several proteins were obtained and two were selected to be studied (a human protein called Tau and an unknown protein described by our group and named hlscA). Both Tau and hIscA cDNA were transformed into an expression plasmid to obtain their recombinant proteins. RESULTS Using a Western-blot technique we investigated the presence of anti-Tau and anti-hlscA autoantibodies in the sera of 19 patients with Sjögren's syndrome and in the sera of 20 controls. No statistically significant differences were found in the expression of anti-Tau antibodies between patients with Sjögren's syndrome and controls but values of anti-hlscA autoantibodies were significantly lower in patients with Sjögren's syndrome. CONCLUSION We identified Tau and hIscA proteins as new autoantigens in Sjögren's syndrome. Anti-hlscA antibody values were significantly lower in patients with Sjögren's syndrome than in healthy controls. Although no statistically significant differences in values of anti-Tau antibodies were found between Sjögren's syndrome patients and controls, this is the first time antibodies against this protein have been detected in Sjögren's syndrome.