title: Role of scintigraphy with ⁹⁹mTc-infliximab in predicting the response of intraarticular infliximab treatment in patients with refractory monoarthritis.
abstract: OBJECTIVE
  The rationale for the present study was to evaluate the predictive role of (99m)Tc-infliximab scintigraphy in therapy decision-making in patients with refractory monoarthritis and also candidates for intraarticular (IA) infliximab treatment.
  
  
  METHODS
  We studied 12 patients (5 with rheumatoid arthritis and 7 with spondyloarthropathy) with active monoarthritis (11 knees and 1 ankle) that had lasted for at least 3 months. Patients were evaluated clinically and ultrasonographically at baseline and 12 weeks after IA administration of infliximab. At the same time-points, (99m)Tc-infliximab scintigraphy was performed: planar anterior and posterior images of arthritic joints were acquired at 6 and 20 h after injection and target-to-background (T/B) ratios were calculated.
  
  
  RESULTS
  After treatment, a significant improvement in clinical and ultrasonographic parameters was recorded in six patients. Three patients had a partial response and three did not respond. Regarding scintigraphic evaluation, the T/B ratio analysis showed a significantly higher uptake in affected than in nonaffected joints before therapy (1.78 ± 0.46 vs. 1.29 ± 0.27, p = 0.006 at 6 h; 2.05 ± 0.50 vs. 1.41 ± 0.36 at 20 h, p = 0.002), and mean uptake at 20 h was also significantly higher than at 6 h (p = 0.0004). Scintigraphy showed a significant decrease in posttherapy T/B ratios of the affected joints (p = 0.0001 at 6 h and p = 0.0001 at 20 h), indicating a reduction in TNF into the affected joints. Most importantly, responders showed a significantly higher percentage increase in pretherapy uptake from 6 h to 20 h in the affected joints than nonresponders (p = 0.00001).
  
  
  CONCLUSIONS
  The results of the present investigation suggest that (99m)Tc-infliximab scintigraphy could be a useful tool to predict the clinical response to IA infliximab treatment in patients with refractory monoarthritis.
authors.affiliation: Rheumatology Unit, Faculty of Medicine and Dentistry, Sapienza University of Rome, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Conti
authors.forename: G
authors.initials: G
authors.lastname: Malviya
authors.forename: F
authors.initials: F
authors.lastname: Ceccarelli
authors.forename: R
authors.initials: R
authors.lastname: Priori
authors.forename: A
authors.initials: A
authors.lastname: Iagnocco
authors.forename: G
authors.initials: G
authors.lastname: Valesini
authors.forename: A
authors.initials: A
authors.lastname: Signore
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D001168:Arthritis / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000628:therapy*; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000628:therapy; D003657:Decision Making; D004351:Drug Resistance; D005260:Female; D006801:Humans; D000069285:Infliximab; D007596:Joints; D008297:Male; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D014463:Ultrasonography
chemical_list: D000911:Antibodies, Monoclonal; D015609:Organotechnetium Compounds; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab