Use of 99mTc-anti-CD3 scintigraphy in the differential diagnosis of rheumatic diseases.

OBJECTIVES

The aim of this study was to assess the use of anti-CD3, labelled with technetium-99m scintigraphy, for evaluating the joints of patients with RA, juvenile idiopathic arthritis (JIA), OA and gouty arthritis, and to establish the diagnosis parameters for each disease.

METHODS

We evaluated 2044 joints from 77 patients with rheumatic diseases. The clinical evaluation consisted of laboratory assays; examination for joint inflammation (pain and/or oedema); and for patients with RA, the disease activity score of 28 joints. To evaluate the sensitivity and specificity of 99mTc-anti-CD3 in detecting disease activity, patients received an injection of the radiopharmaceutical compound 99mTc-anti-CD3, and underwent a scintigraphy scan 1 h later. Scanning was repeated 3 h later. As a control, after 2 days, the patient was injected with 99mTc-non-specific human immunoglobulins, and scintigraphy scanning performed at 1 and 3 h after the injection. The intensity of uptake and the pattern of activity were defined, and Spearman's correlation and analysis of variance used for statistical evaluation.

RESULTS

Diagnosis criteria were established for 99mTc-anti-CD3 uptake in different diseases. RA and JIA showed joint uptake with progressive increase in late images. Gouty arthritis showed joint uptake with decrease during the late images. Joint uptake was low or absent in patients with OA, although when present the joint uptake decreased during the examination.

CONCLUSION

99mTc-anti-CD3 scintigraphy is a useful method in the differential diagnosis of rheumatic diseases.