INTRODUCTION: Visualization of the CD20-antigen expression could provide a tool to localize sites of inflammation and could be of additive value in the diagnosis, and subsequently, in the treatment follow-up of patients with rheumatoid arthritis. In this study, an anti-CD20 monoclonal antibody, rituximab (Mabthera®), was radiolabeled with ¹²⁴Iodine. We report the first results of I¹²⁴-rituximab PET/CT in patients with rheumatoid arthritis. METHODS: Eligible patients received 50 MBq ¹²⁴I-rituximab. Wholebody PET/CT imaging was performed at 10 min, 24 h, 48 h and 72-96 h post injection. Images were evaluated primarily on a visual basis and were correlated with disease activity as determined by physical examination and clinical measures. RESULTS: Joints with visually detectable targeting of ¹²⁴I-rituximab were observed in 4 out of 5 evaluable patients. Only the images at 24 h and later showed accumulation in joints, indicating that the visualized signal represented active targeting of rituximab to the CD20 antigen. Several images showed CD20 positive B-cell infiltration in joints which were clinically normal, while a few clinically diagnosed arthritis localizations were not visualized. This discrepancy suggests that infiltration of CD20 positive B-cells in synovium is a phenomenon that is at least partially independent of clinical inflammation. The level of uptake in joints was generally low, representing less than 0.5% of the injected dose. CONCLUSION: We have shown the feasibility of CD20 antigen imaging using ¹²⁴I-rituximab in patients with rheumatoid arthritis. Further research is needed to elucidate the clinical significance of demonstrated B-cell infiltration in rheumatic joints.
INTRODUCTION: Visualization of the CD20-antigen expression could provide a tool to localize sites of inflammation and could be of additive value in the diagnosis, and subsequently, in the treatment follow-up of patients with rheumatoid arthritis. In this study, an anti-CD20 monoclonal antibody, rituximab (Mabthera®), was radiolabeled with ¹²⁴Iodine. We report the first results of I¹²⁴-rituximab PET/CT in patients with rheumatoid arthritis. METHODS: Eligible patients received 50 MBq ¹²⁴I-rituximab. Wholebody PET/CT imaging was performed at 10 min, 24 h, 48 h and 72-96 h post injection. Images were evaluated primarily on a visual basis and were correlated with disease activity as determined by physical examination and clinical measures. RESULTS: Joints with visually detectable targeting of ¹²⁴I-rituximab were observed in 4 out of 5 evaluable patients. Only the images at 24 h and later showed accumulation in joints, indicating that the visualized signal represented active targeting of rituximab to the CD20 antigen. Several images showed CD20 positive B-cell infiltration in joints which were clinically normal, while a few clinically diagnosed arthritis localizations were not visualized. This discrepancy suggests that infiltration of CD20 positive B-cells in synovium is a phenomenon that is at least partially independent of clinical inflammation. The level of uptake in joints was generally low, representing less than 0.5% of the injected dose. CONCLUSION: We have shown the feasibility of CD20 antigen imaging using ¹²⁴I-rituximab in patients with rheumatoid arthritis. Further research is needed to elucidate the clinical significance of demonstrated B-cell infiltration in rheumatic joints.
Authors: Paulo Henrique Rosado-de-Castro; Sergio Augusto Lopes de Souza; Dângelo Alexandre; Lea Mirian Barbosa da Fonseca; Bianca Gutfilen Journal: World J Orthop Date: 2014-07-18
Authors: Kristian P Doyle; Lisa N Quach; Montse Solé; Robert C Axtell; Thuy-Vi V Nguyen; Gilberto J Soler-Llavina; Sandra Jurado; Jullet Han; Lawrence Steinman; Frank M Longo; Julie A Schneider; Robert C Malenka; Marion S Buckwalter Journal: J Neurosci Date: 2015-02-04 Impact factor: 6.167