Serum level of HE4 was positively correlated with age (r=0.598, p<0.001), disease duration (r=0.297, p=0.006), xerostomia (r=0.345, p<0.001) and xerophthalmia (r=0.257, p=0.007), ESR (r=0.565, p<0.001) and negatively correlated with hemoglobin (r=-0.444, p<0.001). This evidence concerns the gene WFDC2 and Keratoconjunctivitis sicca.