Organ transplant recipients are a high incidence group of tuberculosis infection, and the incidence rate is 7-27 times that of the general population. The prevention of postoperative tuberculosis infection is an important part of kidney transplant recipients postoperative follow-up. Taking reasonable tuberculosis prevention strategies for organ transplant recipients can better prevent the occurrence of postoperative tuberculosis and reduce the unreasonable use of anti-tuberculosis drugs. The previous screening methods for active tuberculosis mainly include sputum smear culture, tissue biopsy, tuberculin skin test, tuberculosis antibody, tuberculosis DNA, and chest imaging. However, there is still a lack of accurate and effective means for screening for latent tuberculosis infection. The tuberculosis interferon-γ release test has recently received more and more attention as a means of screening for potential tuberculosis infection. However, how to apply tuberculosis interferon-γ release test in clinical practice is still controversial. The investigators hope to explore the clinical application prospects and practical value of tuberculosis interferon-γ release test through this research.

According to the conclusion of the retrospective study, the investigators found that the recipients with negative TSPOT result maybe don't need follow the isoniazid treatment to prevent the development of tuberculosis even though participants have clinical risk factor of tuberculosis(include past tuberculosis history, the close contact with active tuberculosis patients, an area with a high incidence of tuberculosis, abnormal chest x ray performance ).

The investigators will divided the recipients with tuberculosis risk factors into three groups randomly. Of course, the invention require written informed consent. The first group with positive tuberculosis interferon gamma release assay (TSPOT) result will follow through with the treatment ,which is a daily dose of isoniazid for six months(300mg daily) after kidney transplant surgery. The second group with negative TSPOT result will not follow through the isoniazid treatment. The third group will follow through with the isoniazid treatment no matter their TSPOT results. The investigators will conduct a prospective clinical trial with the first aim of exploring the effectiveness of TSPOT results in kidney transplant recipients with clinical tuberculosis risk factors, and the second aim of exploring the benefit of the isoniazid treatment follow the TSPOT results rather than clinical risk factors.

Inclusion Criteria:

1. living-donor kidney transplantation;
2. eGFR level > 45ml/min/1.73m2 at discharge;
3. 18<Age <65years;
4. receiving standard triad immunosuppressive regimen

Exclusion Criteria:

1. alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 2.5 or more of upper limit of normal
2. Combined with HBV/HCV/HIV/TB infection in the donor or recipient;
3. Malignancy history in the donor and recipient;
4. organ transplant history in the recipient.
5. The positive TSPOT result or past TB history in the donor