C4A and interstitial lung disease: CRP: 97.23 mg/L  ESR: 120 mm/h  CT chest: ILD  RA factor: positive  ANA: 4+ RIM  IgG: >2,535 (540–1,610)  IgA: 436 (70–250)  C3: 166 mg/dl (89–187)  C4: 20 mg/dl (16–38)  Anti ds-DNA: 10.8 IU/ml (<25- Negative)  Serum IL-6: 3,700 pg/ml  Serum IL-10: 13,900 pg/ml  Interferon levels elevated