SSB and systemic lupus erythematosus: Zuo et al. [45], in their study on 18 RA, 23 heathy control, 24 pSS, and 18 SLE patients concluded that both anti-SSA/Ro and anti-M3R reflect a critical distribution and are most likely to enhance noninvasive identification of individuals with SS .Furthermore, a portion of SS patients with negative anti-SSA/Ro, anti-SSB/La, were positive for anti-M3R suggesting some individuals may benefit from inclusion of anti-M3R testing for SS diagnosis.