This is a 52-week, randomized, open and routine treatment controlled study. This study will assess the safety and efficacy of basiliximab as an add-on treatment for interstitial pneumonia in clinical amyopathic dermatomyositis (CADM) patients. 100 CADM patients are planned to be enrolled in a single center.

Inclusion Criteria:

• Fulfill Sontheimer-Bohan-Peter diagnosis criteria for dermatomyositis.
• Agreement of contraception.
• Serum creatine Kinase ≤ 1.5 fold of upper normal level.
• Interstitial pneumonia:

(meet at least two in four of following)

1. interstitial pneumonia images in high resolution CT;
2. DLCO (diffusing capacity)≤ 60% predict in lung function test;
3. elevated serum KL-6;
4. serum anti-MDA5 (+).

Exclusion Criteria:

• Previous application of immunosuppressives or any target treatment for dermatomyositis.
• Clinically significant active infection including ongoing and chronic infections History of human immunodeficiency virus (HIV).
• Confirmed Positive tests for hepatitis B or positive test for hepatitis C Active tuberculosis.
• Abnormal renal function at screening (serum creatine>300μmol/L，or eGFR<60mL/min/1.73m2, or end-stage renal disease).
• Abnormal liver function test at screening (ALT, AST or total bilirubin over 2 fold of upper normal level.
• History of any malignancy.