C4A and xerostomia: In another study, young-onset SS (age at diagnosis < 35 years) correlation with xerostomia (P = 0.008), abnormality of Schirmer’s test and/or Rose Bengal staining (P = 0.03), positivity of anti-Ro/SS-A antibodies (P < 0.001), low complement C3 (P = 0.018) and low complement C4 levels (P = 0.017), compare to age at diagnosis > 35 years [33].