In contrast to these observations, both parenteral administration of moderate doses of IFNα, that is 1 to 2.3 × 106 IU once to three times weekly respectively, or oral administration of low levels of IFNα (150 IU three times a day), have been reported to relieve the symptoms of xerostomia and xerophthalmia in patients with primary Sjogren’s Syndrome [73,74,75,76,77,78,79]. This evidence concerns the gene IFNA2 and Keratoconjunctivitis sicca.