Acute graft-versus-host disease (aGVHD) is the most common life-threatening complication of allogeneic hematopoietic stem cell transplantation. The recognized first-line treatment for grade 3-4 aGVHD is systemic glucocorticoid. However, there is no recognized second-line treatment for grade 3-4 steroid-resistant aGVHD (SR-aGVHD). The investigators try to observe the efficacy and safety of early application of anti-CD25 monoclonal antibody(basiliximab) combined with ruxotilinib in the treatment of severe SR-aGVHD.

Adults ages 18-65 with grade 3-4 SR-aGVHD

Design

Participants with grade 3-4 steroid-refractory acute GVHD (progression after 3 days or lack of improvement after 5 days of 1.5-2 mg/kg/d systemic steroids) receive combined therapy of basiliximab and ruxolitinib.

Basiliximab is given 20mg twice a week for week 1, and then once a week until GVHD of the participants reaches grade 1(3 episodes for minimum).

Ruxolitinib is given 5mg twice a day for one day and then escalates to 10mg twice a day if the participant is not administered with triazole antifungal agent.

The drug dose will be adjusted according to participants' clinical manifestations, blood cell count, infection status and so on.

For participants with lower gastrointestinal GVHD, intravenous cyclosporine or tacrolimus is given and plasma concentration is monitored in a safe and effective range.

Best supportive treatment is given, including broad-spectrum anti-infection, nutrition support, and blood transfusion.

The investigators access the efficacy and safety of second-line therapy once a week from day 14 until complete remission is received. Then the investigators access the hematological disease status, aGVHD, cGVHD, infection state once a month.

Inclusion Criteria:

• Clinical diagnosis of primary grade 3-4(according to MAGIC criteria) steroid-resistant acute graft-versus-host disease(progression after 3 days or lack of improvement after 5 days of systemic 1.5-2 mg/kg steroids).
• Age 18-65.
• ECOG score≤3.
• Must be able to understand and willing to participate in the study and sign the informed consent.

Exclusion Criteria:

• Refractory/secondary graft-versus-host disease.
• Severe complications such as myocardial infarction, chronic cardiac insufficiency, hepatic failure, renal insufficiency, etc.
• Clinically uncontrolled active infections.
• Other Malignant tumors with progression.
• Ecg: QT interval > 450 ms.
• Allergic to arsenic agent.
• Pregnant or lactating women.
• Expected survival <60 days.
• Undergoing other drug clinical trials.