In Vivo Evaluation of TNF-Alpha in the Lungs of Patients Affected by Sarcoidosis

Introduction. Sarcoidosis is a multisystemic granulomatous disorder characterized by multiple noncaseating granulomas involving intrathoracic lymph nodes and lung parenchyma. Recently, the use of anti-tumor necrosis factor alpha (anti-TNFα) agents has been introduced for therapy of chronic and refractory sarcoidosis with controversial results. Infliximab (Remicade) is a chimeric monoclonal antibody (mAb) that recognizes and binds TNFα, neutralizing its biological effects. In the present study, ( ) (99m)Tc labelled infliximab was used to study the expression of TNFα in sarcoid lesions and to evaluate its role as a predictive marker in response to therapy with Remicade. Material and Methods. A total of 10 patients with newly diagnosed sarcoidosis were enrolled together with 10 control patients affected by rheumatoid arthritis. All patients were studied by planar imaging of the chest with ( ) (99m)Tc-infliximab at 6 h and 24 h and total body [(18)F]-FDG PET/CT. Regions of interest were drawn over the lungs and the right arm and target-to-background ratios were analysed for ( ) (99m)Tc-infliximab. SUV(mean) and SUV(max) were calculated over lungs for FDG. Results and Discussion. Image analysis showed low correlation between T/B ratios and BAL results in patients despite positivity at [(18)F]-FDG PET. Conclusion. In conclusion, patients with newly diagnosed pulmonary sarcoidosis, with FDG-PET and BAL positivity, showed a negative ( ) (99m)Tc-infliximab scintigraphy.