Autoantibodies Agains Cerebral Muscarinic Cholinoceptors in Sjögren Syndrome

REINA SILVIA, ORMAN BETINA, STERIN-BORDA LEONOR, BORDA ENRI

Potrero de los Funes, San Luis, Argentina

Congreso; XXXVI Reunion Anual; 2003

Sociedad Argentina de Investigaciones Odontológicas

Previous studies have demonstrated that antibodies agains tmuscarinic acetylcholine receptors (mAChRs) from exocrine glands , correlates the Sjögren síndrome (SS) in the majority of patients. The aim of the present investigation was to establish if serum IgG antibodies present SS interacts with cerebral mAChRs. Results show that anti-cerebral IgG are present in the sera of 40% SS patients studied. Autoantibodies reable to interact with mAChRs of cerebral frontal cortex membranes inhibiting the [H]QNB binding to its specific receptor. Moreover, tested by ELISA and dot blot they recognized the synthetic peptides corresponding to the second extracellular loop of human M1 and M3 mAChR. In addition, the corresponding affinity-purified anti-M1 and anti-M3 peptide IgGs displayed antagonistic activity, stimulating phosphoinositide hydrolysis. The results support the notion that serum IgG autoantibodies in SS patients target cerebral mAChRs may have some role in the pathogenesis of higher cognitived dysfunction present in SS patients.