The study was terminated based on its primary and secondary outcome measures in three consecutive patients.

The aim of this single-center prospective study is to evaluate the efficacy and safety of Tocilizumab (TCZ), humanized monoclonal antibody against IL-6receptor, in the treatment of refractory Uveitis of Behçet's disease (BDU), to verify its effects on decreasing the dose of cortical steroids, and to determine whether it can reduce BDU recurrence.

Uveitis of Behçet's disease (BDU) is the most common form of ocular manifestations, which is also the leading cause of irreversible visual impairment. The aim of the study is to Improve treatment strategy of the disease as well as to reduce blindness.

Tocilizumab (TCZ) is a humanized antibody against IL-6 receptor, clinical trials on non-infectious uveitis and retrospective study on BDU has obtained expected results.

This single-center prospective study is to evaluate the efficacy and safety of TCZ in the treatment of refractory BDU, to verify its effects on decreasing the dose of corticosteroids, and to determine whether it can reduce BDU recurrence.The investigators aim to enroll nine refractory BDU patients with acute onset uveitis, with difficulty tapering corticosteroids while being treated with at least one of the commonly used immunosuppressants. All participants will receive TCZ , oral corticosteroids and immunosuppressants will remain unchanged, intraocular injection will be avoided. During monthly follow-up, the investigators will measure and record intraocular inflammation status，as well as extraocular manifestations and the acute-phase reactants. The participants will continue to receive TCZ for six months, the primary end point is the efficacy four weeks after first dose of TCZ, secondary end points other than intraocular inflammation will be achieved on each follow-up visit, as quality of life improvements, side effects, recurrence of uveitis, and corticosteroids-tapering effects.

On statistical analysis, the self-control treatment efficiency and recurrence rate difference will be determined using T-test of paired samples at a significance level of 0.05(2-sided).

To ensure the interest of the participants, the study has been reviewed by the PUMCH ethics committee, and drug clinical research liability insurance was prepared.

Inclusion Criteria:

• All participants fulfill the the proposed International Criteria for BD, either ISG criteria(1990) or ICBD criteria(2013).
• All participants present with refractory BDU , acute onset uveitis, either posterior segment involvement or panuveitis, with difficulty tapering corticosteroids while being treated with at least one of the commonly used immunosuppressants, without severe extraocular manifestations.

Exclusion Criteria:

• Patients with impaired hepatic and renal function, other severe ocular diseases, active tuberculosis, viral hepatitis, malignancy, pregnancy will be excluded.