Scintigraphic evaluation of disease activity in rheumatoid arthritis: a comparison of technetium-99m human non-specific immunoglobulins,leucocytes and albumin nanocolloids

Technetium-99m-labelled, non-specific, polyclonal, human immunoglobulin G (^99mTc-hIG) has been used to quantify synovial inflammation in rheumatoid arthritis. A comparison was carried out between the scintigraphic results obtained with this tracer, ^99mTc-hexamethylpropylene amine oxime-labelled white blood cells (^99mTc-WBC) and ^99mTc-albumin nanocolloids (^99mTc-NC). Twenty patients affected by rheumatoid arthritis and suffering from clinically active synovitis were studied with ^99mTc-hIG. The number and sites of the involved joints had been previously assessed on the basis of the presence of pain and/or swelling. A radiological examination had already been carried out on all the joints. Two days after the ^99mTc-hIG scan, 10 patients (group 1) underwent ^99mTc-WBC scintigraphy and the other 10 (group 2) underwent a ^99mTc-NC scan. The results show that the results of ^99mTc-hIG and^99m Tc-NC scans are in agreement with clinical examinations in the majority of cases. However, a certain number of positive joint scans corresponding to negative clinical examinations was found. The numerical distribution of these results according to the radiological stages seems to show that^99m Tc-hIG is more useful than ^99mTc-NC in the initial phases of the disease. The ^99mTc-WBC scan was negative in a consistent percentage of the joints previously assessed as clinically and ^99mTc-hIG scan positive.Offprint requests to: M. Liberatore