BTG3 and interstitial lung disease: The serological domain includes high ANA titre ≥ 1:320 and RF level > 2 times the upper limit of normal, based on previous studies that demonstrate ANA and RF at these levels is more commonly associated with UCTD-ILD and AIF-ILD when compared with idiopathic ILD, where the ANA titre is more commonly ≤1:80 [9,128,129,132].