C4A and Keratoconjunctivitis sicca: Patients who had longer duration of pSS (more than 10 years) showed a higher prevalence of xerophthalmia, abnormality of Schirmer’s test and/or Rose Bengal staining and other systemic involvements (parotid enlargement, lung involvement, vasculitis, or peripheral neuropathy), laboratory findings (positivity of anti-SSA/Ro antibody, anti-SSB/La antibody, and low complement C4 level) in a univariate analysis.