Takebumi Onda

Characterization of cord-blood-derived human mast cells cultured in the presence of Steel factor and interleukin-6.

We generated > 10(7) mast cells by culturing 10(7) cord blood mononuclear cells for > 10 weeks in the presence of Steel factor, interleukin-6 and prostaglandin E2. 99% of the cultured cells had tryptase-positive granules, while 18% had chymase-positive granules. Cultured mast cells contained 3.6 micrograms histamine and 3.5 micrograms tryptase per 10(6) cells. Cells sensitized with 1 microgram/ml human IgE released 58.5% histamine and 1.55 ng tumor necrosis factor (TNF)-alpha per 10(6) cells when challenged with 1 microgram/ml antihuman IgE, whereas the control cells spontaneously released 3.7% histamine and 0.18 ng TNF-alpha. Analysis for surface antigens revealed that cultured mast cells expressed the following CD molecules: 9, 13, 14, 29, 33, 38, 43, 44, 45RA, 45RB, 46, 47, 48, 49d, 50, 51, 53, 54, 55, 58, 59, 60, 61 and 117 (c-Kit). Taken together, these cultured cells seem to be functionally mature mast cells.

Study of Liver Function in Infants with Atopic Dermatitis Using the 13C-Methacetin Breath Test

Serum glutamic-oxaloacetic transaminase (GOT) levels were determined in 214 infants (133 males and 81 females) with atopic dermatitis during their first visit to the Department of Allergy, National Childrens Hospital, Tokyo, Japan. Compared with the normal hospital range, their levels were found to be significantly higher, a tendency which was more conspicuous in lower age groups. We carried out a 13C-methacetin breath test (MBT), administering the stable-isotope-labeled compound to 11 children with higher serum GOT values and 5 within the normal range to investigate hepatic metabolism of methacetin in infants with atopic dermatitis. 13C-methacetin was given orally, and the 13CO2 level in the breath was determined immediately before and after administration, by mass spectrometry. Compared to the normal controls, the atopic infants demonstrated significantly lower 13CO2 peak excretion and delayed peak time. The clearance rate of 13CO2 was also decreased. These results suggest some relationship between atopic dermatitis and liver function in infants.

Relationship between histamine release and leukotrienes production from human basophils derived from atopic dermatitis donors

Basophils are known to release histamine and to produce leukotrienes (LTs) following both IgE-dependent and -independent stimuli. Although there exist a few reports which examined the relationship between histamine release and LTs production, their conclusions were not always in agreement with each other. In the present study, we examined the relationship between histamine release and LTs production from basophils in the presence or absence of 1 ng/ml of interleukin-3 (IL-3). Normal basophils released a smaller amount of histamine and LTs than atopic determatitis (AD) basophils, when basophils were stimulated with an optimal concentration of anti-IgE antibody. When we examined the relationship of histamine release and LTs production from AD donors induced through Fc epsilon RI, we found a significant exponential correlation between these two mediators (R2 = 0.58 in the absence of IL-3, R2 = 0.83 in the presence of IL-3). Although IL-3 enhanced both histamine release and LTs production from AD donors, the relationship between these two mediators was not affected. In conclusion, there was an exponential correlation between histamine release and LTs production from AD basophils, which was not affected by the pretreatment with IL-3.