Rheumatic heart disease usually accompanied by weakened immune function. And the cardiopulmonary bypass further aggravating the decline of immune function. Therefore, the prevention of Postoperative immune function collapse is of great clinical value, and immunomodulatory therapy with thymosin alpha

1 may be beneficial. This study was designed to test the hypothesis that the administration of thymosin alpha 1 will Improve the immune function and prognosis of patients.

Inclusion Criteria:

• The patients are conformed to 2004 WHO guidelines for Rheumatic fever and rheumatic heart disease;
• Patients planning to undergo cardiac surgery were enrolled.
• The patients' age between 18 ~80 years old.
• Agree to participate in the study and sign the informed consent.

Exclusion Criteria:

• Patients allergic to Thymosin α1;
• Lactating women and pregnant women;
• Patients with mental diseases, drug and alcohol dependence;
• Refuse to participate in this study and refuse to sign the informed consent