Dynamic evaluation of the response to specific immunotherapy

Full text: Objectives: Evaluate in vivo response to specific immunotherapy in maintenance status, with leukocytes labelled with 99mTc-HMPAO. Methods: The leukocytes were labelled with 99mTc-HMPAO using the standard technique. After resuspension the labelled white cells with cell-free plasma they were injected intravenously in a peripheral vein faraway from the place where the therapeutic allergen suspension was applied. The both two administration were made at the same time. Simultaneously with the two injections, a 90 min dynamic acquisition, at thorax level, 64x64 matrix, at two frame/minute in anterior view, was carried out through a gamma camera. Static images, 256x256, 5 minutes, at 2, 3, 4, 5, 6, 8 and 21 hours after injections, of thorax and pelvis in anterior view, were acquired. During the examination, the local erythema was monitored. Results: The results obtained show that 40 min after injection local inflammatory activity at the IT administration place, with a progressive increase of local activity. 60 minutes after injection, ascendant lymphatic drainage directed to the homolateral axillary region ant to the lymphoid tissue of the upper mediastinum and anterior region of the neck were visualized. The static images show a progressive improvement of the inflammatory area corresponding to the place where IT was applied, with individualization of focal supraclavicular areas, bilaterally. In the latter images, thoracic, mediastinal, bowel and upper cervical localizations, were observed. Discussion and conclusions: In the patients studied, the specific IT shows great efficiency linked with the tolerability to different allergens (provocation test) achieved and with a significant fall of the Prick reactivity. However, at the aqueous extract application place, the local erythema with papula is always less than 60 mm. In these patients, the inflammatory response was significantly bigger in depth, time dependent, even after complete disappearance of the erythema. These results were conformed by the images. The progressive involvement of lymphatic nodes, bone marrow, BALT, GALT and MALT, with good visualization at the latter images, corresponding to an immune response induced by the subcutaneous IT. (author)