To detect anti-M3 receptor antibodies in primary Sjögren's syndrome (pSS) patients and to explore its association with clinical manifestations.
Anti-M3 antibodies were tested in 70 patients with pSS , 50 patients with systemic lupus erythematosus (SLE) and 76 normal controls with ELISA and Western blot. The correlation between anti-M3 antibodies and other clinical manifestations was analyzed.
(1) The positive rate of anti-M3 antibodies in pSS was 47.14% using ELISA and 60.00% using Western blot in SLE 4.00% using ELISA and 12.00% using Western blot and in normal controls 14.47% using ELISA and 15.79% using Western blot. (2) The incidence of schirmer test, tear break-up time (BUT), whole saliva flow rate, punctate epithelial erosions (PEE) on the corneas and external eye examination were not significantly different between the anti-M3 positive and negative groups. (3) The incidences of IgG, rheumatoid factor, SSB and fluorescence index (FI) > 3 were higher in the positive group than in the negative group using ELISA.
The positive rate of anti-M3 antibodies is higher in pSS than in SLE and normal controls and in some degree it has correlation with the lesion in salivary gland.