Although stem cell factor (SCF) has been identified as a critical cytokine for the development of human mast cells from their progenitors, the effects of other cytokines on human mast cells are less well understood. We examined the effects of several cytokines on the survival of human mast cells of 100% purity generated in suspension cultures of umbilical cord blood mononuclear cells in the presence of 100 ng/mL recombinant human (rh) SCF and interleukin-6 (IL-6). Mast cells suspended in conventional serum-containing medium died over a period of 2 to 6 days after the withdrawal of SCF and IL-6. The cells became pyknotic and underwent DNA fragmentation characteristic of apoptosis. The addition of SCF, IL-3, IL-4, IL-5, or IL-6 to the cultures in both serum-containing and serum-free medium prolonged their survival in a dose-dependent manner. Some other cytokines, such as IL- 2, IL-9, IL-10, IL-11, tumor necrosis factor-alpha, transforming growth factor-beta 1, and nerve growth factor, had no survival-promoting effect at 100 ng/mL. Preincubation of mast cells with SCF, IL-4, IL-5, or IL-6 for 24 hours during sensitization with IgE enhanced IgE/anti- IgE antibody-induced histamine release from mast cells, whereas IL-3 showed a negligible effect. Polymerase chain reaction amplification of alpha-chains of IL-3 receptor (R), IL-4 R, IL-5 R, and IL-6 R yielded products of the correct size predicted from the sequence of each receptor. The binding assay using 125I-labeled IL-3 indicated that these mast cells bear receptors for IL-3. These findings suggest that IL-3, Il-4, IL-5, and IL-6, which are mainly produced by T-helper 2 lymphocytes, might regulate the functions of human mast cells in vivo via specific receptors in allergic reactions.

Background: Buckwheat is becoming popular in many countries as a health food and the incidence of buckwheat allergy is increasing in Asia. The ingestion of small amounts sometimes provokes an anaphylactic reaction. However, it remains controversial which is the major allergen responsible for such reactions. Methods: The patients whose sera are positive for buckwheat-specific IgE antibody measured by the CAP system fluorescein-enzyme immunoassay (CAP-FEIA) were classified into two subgroups depending on the history of immediate hypersensitivity reactions (IHR). Major buckwheat allergens were identified with immunoblotting, ELISA and N-terminal amino acid sequencing. Various treatments such as pepsin digestion were added to characterize the proteins. Results: We found that the 24-kD protein that had previously been reported to be a major allergen reacted to IgE antibodies present in sera from almost all subjects (19/20) regardless of symptoms. On the other hand, 16- and 19-kD proteins were bound with IgE antibodies present in sera from 9 of the 10 patients with IHR including 8 patients with anaphylaxis but not in sera from buckwheat-specific IgE-positive subjects without IHR. After pepsin treatment, the 16-kD protein but not the 19- and 24-kD proteins remained undigested and preserved the capacity of IgE binding. This pepsin-resistant 16-kD protein had no homology with the 24-kD protein by the N-terminal amino acid sequencing. Conclusions: The 16-kD buckwheat protein was resistant to pepsin digestion and appeared to be responsible for IHR including anaphylaxis, while the pepsin-sensitive 24-kD protein was responsible for CAP-FEIA but not IHR.

We generated > 10⁷ mast cells by culturing 10⁷ 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 μg histamine and 3.5 μg tryptase per 10⁶ cells. Cells sensitized with 1 μg/ml human IgE released 58.5% histamine and 1.55 ng tumor necrosis factor (TNF)-α per 10⁶ cells when challenged with 1 μg/ml antihuman IgE, whereas the control cells spontaneously released 3.7% histamine and 0.18ng TNF-α. 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.

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Poor adherence to maintenance treatment for atopic dermatitis and anxiety about using topical steroids are common features seen among children with atopic dermatitis and their mothers. No systematic study exploring factors associated with adherence to treatment advice on atopic dermatitis has been carried out to date. This study seeks to generate hypotheses regarding the relationship between a range of psychosocial factors and adherence to treatment advice on atopic dermatitis. An anonymous self-completed questionnaire containing adherence items, psychosocial items, some demographic items, and attitudes to steroid use was given to 258 mothers of atopic dermatitis follow-up patients who attended the National Children's Hospital, Tokyo. Responses from 205 families (80%) with complete data were then analyzed to explore the correlation between each factor and to build a structure equation model. The strongest predictor of adherence to skin-care treatment was a good doctor-patient (mother) relationship, followed by the severity of the disease as perceived by the mother. Surprisingly, the mother's anxiety about using topical steroids had no significant influence on reported use of topical steroids nor on adherence to skin-care treatment. This may have been overcome by the well-established doctor-patient (mother) relationship. Maternal personality, husband's cooperation, and social support were indirectly correlated with adherence via the doctor-patient relationship. Maternal self-efficacy of treatment was strengthened by good doctor-patient (mother) relationship.