Diffuse large B-cell lymphoma successfully treated with amplified natural killer therapy alone: A case report

BACKGROUND: The prognosis of patients with advanced diffuse large B-cell lymphoma (DLBCL) is poor, with a 5-year survival rate of approximately 50%. The mainstay of treatment is multidrug combination chemotherapy, which has been associated with serious side effects. Amplified natural killer (ANK) cell therapy amplifies and activates natural killer (NK) cells to attack only malignant tumors. As ANK cells attack programmed death ligand 1 (PD-L1)-positive tumor cells, ANK therapy is considered effective against adult T-cell lymphoma and malignant lymphoma. CASE SUMMARY: Herein, we report a case of an older patient with advanced DLBCL who was successfully treated with ANK immunotherapy. A 91-year-old female visited our hospital with sudden swelling of the right axillary lymph node in April 2022. The patient was diagnosed with stage II disease, given the absence of splenic involvement or contralateral lymphadenopathy. ANK therapy was administered. Six rounds of lymphocyte sampling were performed on July 28, 2022. To reduce the occurrence of side effects, the six samples were diluted by half to obtain 12 samples. Cultured NK cells were administered twice weekly. The treatment efficacy was evaluated by performing computed tomography and serological tests every 1 or 2 mo. The treatment suppressed lesion growth, and the antitumor effect persisted for several months. The patient experienced mild side effects. PD-L1 immunostaining was positive, indicating that the treatment was highly effective. CONCLUSION: ANK therapy can be used as a first-line treatment for malignant lymphoma; the PD-L1 positivity rate can predict treatment efficacy.