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Surgical human thymus, upper respiratory tract, lung and small and large bowel specimens were analyzed for the presence of interleukin 2 receptor (IL2-R)-positive cells. Histochemical (toluidine) and immunologic (anti-IL2-R monoclonal antibody) staining procedures revealed a distinct anti-IL2-R positivity in most of metachromatically staining cells. These positive cells were observed not only in tissues showing strong inflammatory reaction and mast cell hyperplasia, as in Crohn's disease, but also in those not histologically affected by pathologic conditions. This finding suggested that human mast cells, like T blast cells, express the p55 chain of IL2-R on their surface. To see whether IL2-R was being actively synthesized, a cell preparation rich in peripheral blood basophils (PBB), which are cells closely related to mast cells, was obtained. Ultrastructural analysis of PBB after indirect immunogold procedure revealed that the vast majority expressed the IL2-R. Moreover, the presence of intracellular reaction products in the cytoplasm of most membrane-positive PBB was indicative of active antigen synthesis. Furthermore, Northern blot analysis evidenced specific IL2-R mRNA in PBB, while its expression was augmented several times when PBB were cultured in the presence of stimulated T cell supernatant.

Mast cells were studied by light microscopy in mucosal imprints and in biopsies of nasal mucosa of 12 birch pollen allergic individuals before and during the pollen season, using techniques optimized for the demonstration of mucosal mast cells. We also measured the histamine content of nasal mucosa, whole blood and plasma, and counted the numbers of circulating blood basophils. Before the pollen season the nasal mucosa was found to contain many mast cells located in the mucosal connective tissue stroma, and very few cells with basophilic and metachromatic granules were found in mucosal imprints. During the pollen season there was a redistribution of mast cells into the epithelium, many such cells now being recovered in mucosal imprints. The total number of mucosal mast cells counted in tissue sections did not change significantly with the onset of the pollen season, suggesting a redistribution of mucosal mast cells by migration. Judged by morphologic appearance and naphthol-AS-D chloroacetate esterase activity, the intraepithelial mast cells found in tissue sections had rather the properties of tissue mast cells than of blood basophils, and only a few of the basophilic cells of the imprints had a morphology compatible with blood basophils. The histamine content of the mucosa, as well as histamine levels of whole blood and plasma, and circulating blood basophil numbers did not change significantly in relation to the pollen season. These findings suggest that an intraepithelial migration of mucosal mast cells is part of the allergic mucosal response.(ABSTRACT TRUNCATED AT 250 WORDS)

From the seemingly most appropriate methods for standardization procedures of allergen extracts, the most serious candidates are in sequence of age: the old atopic skin test, the histamine-release test, using human basophil cells and the radio-allergosorbent test. At the moment it is not yet certain which method gives the most exact results, although, especially in the last ones - as part of the whole test - highly sophisticated methods are used. The skin test is not dependent on modern laboratory methods, is used on a world-wide scale, but as method studied very poorly. This is a matter of regret, because at any rate the skin test gives the clinician a lot of valuable information. The major drawbacks of the skin test are that the inclination of the log-dose response line is rather small and that the results of tests done with the same dose may vary sometimes not inconsiderably. Furthermore, the results are dependent on the sites of the skin where the tests are done and on the amount of fluid injected intracutaneously. There is a diurnal variability, a certain influence of the menstrual cycle and of course influence of medicaments (histamines). Nevertheless, taking all these factors into consideration and using a highly perfected method of skin testing, it appeared possible in 16 experiments, with not more than six volunteers per experiment, to reduce the variability of the bioassay between the limits of +50 and minus 50 per cent.