Author(s)

Silvia Reina^1,2, Cecilia Pisoni³, Alicia Eimon³, Carolina Carrizo³, Roberto Arana³, Enri Borda^1,2*

¹Pharmacology Unit, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
²National Research Council of Argentina (CONICET), Buenos Aires, Argentina.
³Section of Rheumatology and Immunology, Department of Internal Medicine, CEMIC, Buenos Aires, Argentina.

Background: Evidences have shown that anti-M₃ muscarinic acetylcholine receptor IgG (anti-M₃ mAChR IgG) are clinically useful autoantibody that exert a cholinergic pharmacologic effect binding and interacting with M₃ mAChR at the level of exocrine gland (salivary and ocular). Aims: The aim of this study was to determine the associations between serum level of anti-M₃ mAChR IgG in patients with systemic lupus erythematosus (SLE) and other autoantibodies, serum prostaglandin E₂ (PGE₂), and clinical manifestations. Methods: Serum autoantibodies against M₃ mAChR synthetic peptide were measured by enzyme-linked immuno absorbent assay (ELISA) using, as an antigen, a 25-mer peptide K-R-T-V-P-D-N-Q-C-F-I-Q-F-L-S-N-P-A-V-T-F-G-T-A-I corresponding to the amino acid sequence of the second extracellular loop of the human M₃ mAChR. Serum levels of antinuclear antibodies (ANA), anti-Smith (Sm) antibodies, anti-phospholipid (APL) antibodies, and PGE₂ were determined by ELISA in patients with SLE. Results: We found significantly enhanced titers of anti-M₃ mAChR IgG in sera from SLE patients compared with healthy individuals (control). In addition, serum levels of PGE₂ were significantly higher in SLE patients than in control patients and were significantly higher in active than in non-active SLE. No correlation was found with other autoantibodies present in SLE. By contrast, a positive correlation was found between anti-M₃ mAChR IgG and PGE₂ serum levels in SLE. Conclusions: As anti-M₃ mAChR antibodies present in the sera of SLE patients may be another factor in the pathogenesis of this disease, and the increment of PGE₂ in the sera of SLE has a modulatory action on the inflammatory process, suggesting that the presence of these autoantibodies against M₃ mAChR may contribute to sustained immune deregulation and the strong inflammatory component observed in SLE.

Anti-M₃ mAChR Antibodies, Systemic Lupus Erythematosus, Prostaglandin E₂

Reina, S. , Pisoni, C. , Eimon, A. , Carrizo, C. , Arana, R. and Borda, E. (2015) Anti-M₃ Muscarinic Acetylcholine Receptor Antibodies in Systemic Lupus Erythematosus. Pharmacology & Pharmacy, 6, 25-33. doi: 10.4236/pp.2015.61004.