Human mAChR Autoantibodies from Sjögren Syndrome Sera Increase Cerebral Nitric Oxide Synthase Activity and Nitric Oxide Synthase mRNA

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

Potrero de los Funes, San Luis, Argentina

Congreso; XXXVI Reunion Anual; 2003

Sociedad Argentina de Investigaciones Odontológicas

We demonstrated the presence of circulating antibodies from Sjögren Syndrome (SS) patients able to interact with rat cerebral frontal cortex activating muscarinic acetylcholine receptors (mAChRs). Serum antibodies (IgG) from SS and normal subjets were studied by flow cytometry, enzyme immunoassay (ELISA) and radioligand binding assays. Cerebral frontal cortex membranes were used as antigens. By flow cytometry procedures, we proved that IgG from SS patients, reacted to cerebral frontal cortex cell surface. The same antibodies were able to inhibit the binding of specific mAChR radioligand 3H-QNB. Also, the IgG from SS patients displayed an agonistic-like activity associated to specific M1 and M3 mAChR activation, stimulating the different nitric oxide synthase (NOS) isoforms and neural (n) and endothelial (e) NOS mRNA levels. This articule gives support the participation of humoral immune alterations in SS, resulting in a central parasympathetic functional deregulation. The chronic fixation of these anti neuronal antoantibodies on cerebral frontal cortex mAChR, could mediated the alterations of cognitive functions observer in SS patients.