CLINICAL UTILITY OF RADIOIMMUNOSCINTIGRAPHY OF NON-HODGKINS-LYMPHOMA WITH RADIOLABELED LL2 MONOCLONAL-ANTIBODY, LYMPHOSCAN(TM) - PRELIMINARY-RESULTS

Aims and background: Adequate clinical staging of non-Hodgkin's lympho ma patients is essential because only localized disease can be treated satisfactorily. Many imaging procedures are necessary to stage the di sease accurately. The objective of this study was to evaluate the effi cacy of an anti-lymphoma antibody in the Fab' fragment form, labelled with (TC)-T-99m, to detect malignant lesions. Methods: Radioimmunodete ction (RAID) with Tc-99m-labelled B-cell lymphoma monoclonal antibody IMMU-LL2-Fab' (LymphoSCAN(TM); Immunomedics, Morris plain, NJ, USA) wa s investigated in 10 patients 15 females and 5 males; age range, 20-72 years) with histologically proved non-Hodgkin's lymphoma. Of the 10 l ymphomas, 7 were intermediate grade and 3 were low grade. Whole body i mages with multiple planar Views were obtained at 30 min, 4-6 and 24 h after i.v. injection of 1 mg LL2-Fab' labelled with 740-925 MBq of (T C)-T-99m. SPET Of the chest or abdomen was performed in ail patients 5 -8 h after the immunoreagent injection. Results: No adverse reactions were observed in any patient after Mab infusion, and no appreciable ch anges were seen in the blood counts, renal or liver function tests. A total of 18 of 21 (85.7%) lymphoma lesions were detected by RAID. All the tumor localizations were confirmed by clinical examination and wit h other imaging techniques, such as CT scan, MRI or gallium scan. In t his series of patients no false-positive results were noted. As regard s the biodistribution of the immunoreagent, no appreciable bone marrow activity was seen; splenic targeting was demonstrated in all patients ; the tumor-to-non-tumor ratios ranged from 1.2 to 2.8 ad measured by the ROI technique; no difference in uptake was noted for different tum or grades. The images obtained 24 h after injection did not reveal new lesions, but areas of doubtful uptake were seen as positive focal are as in the delayed scan. Conclusions: LymphoSCAN(TM) seems to be useful for detection, staging and follow-up of non-Hodgkin's lymphoma patien ts.