To observe the safety, tolerability and clinical effects of PD-1, chidamide, lenalidomide and gemcitabine in the treatment of newly diagnosed and relapse/refractory peripheral T-cell lymphoma.

Patients with peripheral T-cell lymphoma usually have a bad prognosis. These patients cannot be treated successfully with the conventional CHOP regimen. The investigators have been proceeding this trial to evaluate the efficacy and safety of the PD-1, chidamide, lenalidomide and gemcitabine in the treatment of newly diagnosed and relapse/refractory peripheral T-cell lymphoma.

Inclusion Criteria:

• age:14-65 years;Eastern Cooperative Oncology Group (ECOG)score≤3;expected survival≥3 months
• patients with Peripheral T-cell Lymphoma diagnosed by immuno-histochemistry (IHC);
• acceptable hematological indicators, no chemotherapy contraindications;
• total bilirubin ≤ 1.5 times the upper limit of normal (ULN), alanine aminotransferase (ALT) ≤ 2.5 x upper age limit (ULN), if the abnormal laboratory parameters are considered to be caused by lymphoma, patients Eligible conditions should be adjusted to be incorporated into the group;
• At least one measurable lesion by CT or PET-CT（Positron Emission Tomography-Computed Tomography）;
• exclude other major diseases, normal heart and lung function;
• Female patients of childbearing age are negative for pregnancy test;
• Cooperate with follow-up;
• There are no other related treatments including traditional Chinese medicine, immunotherapy, and biologic therapy (except for the treatment of anti-bone metastases and other symptoms);
• Signing informed consent *: Pathological histology must be consulted by a pathologist at a provincial hospital.

Exclusion Criteria:

• Patients with ALK-positive Anaplastic Large Cell Lymphoma or angioimmunoblastic T-cell lymphoma
• rejecting providing blood preparation;
• allergic to drug in this study and with metabolic block;
• rejecting adopting reliable contraceptive method in pregnancy or lactation period;
• uncontrolled internal medicine disease(including uncontrolled diabetes,severe incompetence cardiac, lung, liver and pancreas）；
• with severe infection;
• with primary or secondary central nervous system tumor invasion;
• with immunotherapy or radiotherapy contraindication;
• ever suffered with malignant tumor;
• having peripheral nervous system disorder or dysphrenia;
• with no legal capacity,medical or ethical reasons affecting research proceeding;
• participating other clinical trials simultaneously;
• adopting other anti-tumor medicine excluding this research;
• Patients with immunodeficiency, such as primary immunodeficiency syndrome or organ transplant recipients
• Human immunodeficiency virus (HIV)-positive patients
• the researchers considering it inappropriate to participate in the study.
• Patients with immune system diseases