U1 and scleroderma: ANA: Antinuclear antibodies; Ig: Immunoglobulin; pSS: Primary Sjogren's syndrome associated interstitial lung disease; Anti-SSA: Anti-Sjogren's Syndrome A; Anti-SSB: Anti-Sjogren's Syndrome B; Anti-SSA 52 kD Ab, IgG:  Anti-Sjogren's Syndrome A 52 kD Antibody, immunoglobulin G; Anti SCL 70: Anti scleroderma 70 kD; Anti U1 RNP: Anti-U1-ribonucleoprotein; U3 RNP: U3 ribonucleoprotein.