xXuejun Zhu, Department of Hematology, Jiangsu Provincial Hospital Multiple myeloma (MM) is the second most common malignancy of the hematological system, and the treatment includes: initial treatment with MP, MPT, VAD as first-line regimen, hematopoietic stem cell transplantation, targeted therapy (thalidomide, bortezomib, arsenic, etc.), maintenance therapy and supportive therapy. Currently, polycythemia vera is still considered an incurable disease, with a median survival of only 3-5 years. Immunotherapeutic strategies such as dendritic cell (DC) vaccine for the treatment of multiple myeloma have been more extensively studied in recent years. Foreign clinical trial studies A number of clinical trials applying dendritic cell vaccine immunotherapy for multiple myeloma have been conducted, and the results showed that all patients could tolerate immunotherapy with DC vaccine well, and no serious toxic side effects were observed except for mild febrile reactions and inflammatory reactions at the vaccination site, confirming that the safety of Id-DC and Id-KLH-DC vaccines is good. The humoral immune response of patients to the antigen carrier KLH was as high as 90-100% and the cellular immune response was about 80%, while the specific humoral and cellular immune responses to the Id antigen were relatively low. Bendandi et al. reported four patients with relapsed multiple myeloma who received allogeneic DC-Id -KLH vaccine after treatment failure with reduced-dose allogeneic HSCT and donor lymphocyte infusion, all patients tolerated the treatment better and all induced a KLH antibody response. Dadabayev et al. reported a case of allogeneic stem cell transplantation failure in a myeloma patient treated with SP17 sperm protein-impacted DC at 2-week intervals, followed by 5 days of low-dose IL-2 therapy for 6 vaccinations, which produced an inflammatory response at the local vaccination site, but no serious toxic side effects were observed, and the patient had a 90% decrease in M protein. Our work: We pioneered DC vaccine combined with CIK for myeloma in 2004 in China. Dozens of patients have been treated with ideal outcomes. An elderly patient with plasma cell leukemia (the most serious type of multiple myeloma, with an average survival of only about six months), who had not been in remission after several chemotherapy treatments and whose bone marrow plasma cells reached 20%, was treated with tumor antigen-impacted DC immunization once every 4 weeks for a total of 3 times. The patient survived 37 months after treatment, and another patient with plasma cell leukemia was treated with dendritic cell immunization after chemotherapy resistance and has survived for more than 5 years. DC immunotherapy will likely benefit patients using mixed antigens and in combination with chemotherapy, for example.