CRP: 32 mg/L  ESR: 23 mm/h  HRCT: ILD  IgG: 1,453 mg/dL  IgA: 131 mg/dL  IgM: 135 mg/dL  RA, CCP: Positive  ANA: 3+ speckled  ANCA: negative. Here, BTG3 is linked to interstitial lung disease.