Safety and Efficacy of Anti-FcRL5 CAR-T Cell Therapy in Treating Relapsed and Refractory Multiple Myeloma (R/R MM)

Inclusion Criteria: The set subject inclusion criteria include multiple documents of multiple myeloma, no effective treatment options (e. g. autologous or allogeneic stem cell transplantation) and limited outcome (\<2 years) with existing therapies, as follows: 1. Age is 18\~70 years old; 2. Expected survival period of\>12 weeks; 3. Multiple myeloma was diagnosed by physical examination, pathological examination, laboratory examination and imaging; 4. Patients with refractory multiple myeloma; 5. Patients with multiple myeloma recurrence; 6. ALT and AST \<3 times normal; bilirubin \<2.0mg / dl; 7. Quality of survival score (KPS)\> 50%; 8. The patient has no serious heart, liver, kidney and other diseases; 9. Recurrence or no disease remission after hematopoietic stem cell transplantation or cellular immunotherapy; 10. Is not suitable for stem cell transplantation conditions or to abandon transplantation due to conditional restrictions; 11. Blood can be obtained intravenously, without other contraindications to leukapheresis; 12. Understand and voluntarily sign a written informed consent form. Exclusion Criteria: 1. Women who are pregnant or breastfeeding, or who have a pregnancy plan within six months; 2. Infectious diseases (such as HIV, active tuberculosis, etc.); 3. Active hepatitis B or hepatitis C infection; 4. Feasibility assessment screening demonstrated \<10% transfection of targeted lymphocytes or underamplification under CD3 / CD28 costimulation (\<5-fold); 5. Abnormal vital signs, and unable to cooperate with the examination; 6. Have mental or mental illness who cannot cooperate with the treatment and efficacy evaluation; 7. Highly allergic constitution or have a history of severe allergies, especially allergic to IL-2; 8. Subjects with a systemic infection or a severe local infection requiring anti-infective treatment; 9. Subjects with severe autoimmune disease; 10. The doctor believes there were other reasons for inclusion