Osamu Fukutomi

Lymphocyte responses to food antigens in patients with atopic dermatitis who are sensitive to foods

The proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin or bovine serum albumin in children with atopic dermatitis (AD) who are sensitive to hens egg or cows milk were significantly higher than responses of PBMCs of healthy children and hens egg- or cows milk-sensitive children with immediate symptoms. However, the percentages of positive RAST for hens egg or cows milk in the patients with AD were lower than percentages in the patients with immediate symptoms. In the patients with AD, there were no significant correlations between the proliferative responses of PBMCs and the RAST values. There were no significant differences of RAST scores among groups of patients having different degrees of severity of AD. The proliferative responses of PBMCs to ovalbumin or bovine serum albumin in patients with severe AD or moderate AD who were sensitive to hens egg or cows milk tended to be higher than responses of patients with mild AD, respectively, but there were no significant differences in those results. Taken together, the combination of RAST and the detection of proliferative responses of PBMCs to each food antigen is very useful in the diagnosis of hypersensitivity in children with AD who are sensitive to food allergens.

The role of T lymphocytes in patients with food-sensitive atopic dermatitis

The role of T lymphocytes was assessed in patients with food-sensitive atopic dermatitis (AD). T lymphocytes plus monocytes responded well to ovalbumin or bovine serum albumin (BSA) in children with AD who were sensitive to hens egg or cows milk compared with healthy children and children with immediate allergic symptoms who are sensitive to hens egg or cows milk. The responding cells were shown to be predominantly CD4+ T lymphocytes. Interleukin-2 activity and interferon-gamma concentrations in culture supernatants of ovalbumin-stimulated peripheral blood mononuclear cells (PBMCs) from patients with AD who were sensitive to hens egg were significantly higher than those of healthy children and patients sensitive to hens egg with immediate symptoms. Expression of Fc epsilon R II on B lymphocytes in cultures of ovalbumin-stimulated PBMCs from patients with AD was significantly higher than that of healthy children, but it tended to be lower than that of patients with immediate symptoms. These results suggest that, in patients with AD who are food sensitive, CD4+ T lymphocytes stimulated by food antigens secrete lymphokines such as interleukin-2 and interferon-gamma that are secreted from TH1 clones in mice, and express Fc epsilon R II on B lymphocyte that is induced by interleukin-4 secreted from TH2 clones in mice. Taken together, cell-mediated immunity may also occur in addition to IgE-mediated hypersensitivity in patients with food-sensitive AD.

Effect of elimination diets on food-specific IgE antibodies and lymphocyte proliferative responses to food antigens in atopic dermatitis patients exhibiting sensitivity to food allergens

Peripheral blood mononuclear cells (PBMCs) from patients with atopic dermatitis (AD) selected as being sensitive to hens egg or cows milk responded to food antigens, ovalbumin, or bovine serum albumin, with significantly enhanced DNA synthesis compared with the DNA synthesis in PBMCs from nonatopic control subjects and food-sensitive patients with immediate symptoms. Patients were treated with elimination diets. Symptoms of AD had been in remission during elimination diets. The levels of specific IgE antibodies to hens egg or cows milk decreased during elimination diets in patients with positive radioallergosorbent test (RAST). In patients with negative RAST, specific IgE antibodies remained negative during elimination diets. The proliferative responses of PBMCs to food antigens also decreased during elimination diets in patients with proliferative responses before elimination diets. Taken together, specific IgE antibodies to food antigens are useful indexes of the effect of elimination diets in food-sensitive patients with AD and positive RAST, and proliferative responses of PBMCs to food antigens are useful indexes of the effect of elimination diets in food-sensitive patients with AD and proliferative responses of PBMCs.

Predictive values of cord blood IgE and cord blood lymphocyte responses to food antigens in allergic disorders during infancy

Proliferative response of cord blood lymphocytes stimulated twice by food antigens and cord blood IgE concentration were measured in 131 full-term newborn infants for the prediction of allergic disorders. Through the follow-up study for 2 1/2 years, the value of stimulation index in proliferative response of cord blood lymphocytes to ovalbumin or bovine serum albumin was greater than 1.5 in 17 (sensitivity 53.1%) of 32 infants in whom allergic disorders developed and less than 1.5 in 81 (specificity 81.8%) of 99 infants who had no allergic disorders (cutoff limit of stimulation index 1.5). The sensitivity was increased (71.9%) by the combination of the cord blood IgE concentration (cutoff limit 1.0 IU/ml) and proliferative response of cord blood lymphocytes to food antigens (cutoff limit of stimulation index 1.5). The combination of the cord blood IgE concentration and proliferative response of cord blood lymphocytes to food antigens is useful for the prediction of allergic disorders. Interleukin-2 production of cord blood lymphocytes stimulated with food antigens was also measured in 24 newborn infants. Interleukin-2 activity in culture supernatants of ovalbumin- or bovine serum albumin-stimulated cord blood lymphocytes correlated well with proliferative response of cord blood lymphocytes to ovalbumin or bovine serum albumin.

IGG2 DEFICIENCY ASSOCIATED WITH DEFECTS IN PRODUCTION OF INTERFERON-GAMMA : COMPARISON WITH COMMON VARIABLE IMMUNODEFICIENCY

We report a novel mechanism of IgG2 deficiency. Several investigators have reported patients with IgG subclass deficiencies due to homozygous deletion of immunoglobulin heavy chain constant region genes. However, it is unclear what mechanism is responsible for IgG subclass deficiency in cases where no gene deletions have been detected and which are accompanied by recurrent infections due to aberrant immunoregulation. In the present study, we have focused our attention on production by peripheral blood mononuclear cells (PBMCs) of interferon‐gamma (IFN‐γ), which is known to induce IgG2 expression. PBMCs from four patients with IgG2 deficiency and their families were studied. Mitogen‐induced IFN‐γ production by PBMCs was decreased in all of the patients, although the proliferative responses of PBMCs and the percentages of CD3, CD4, and CD8 T cell subsets were not decreased. IgG2 production by PBMCs was restored upon addition of IFN‐γ and mitogen to the PBMCs of the patients with IgG2 deficiency though it was not restored in the patients with common variable immunodeficiency. We conclude that defects in production of IFN‐γ play an important role in IgG2 deficiency.

Autonomic regulation after exercise evidenced by spectral analysis of heart rate variability in asthmatic children

BACKGROUND Bronchial asthma is associated with abnormal autonomic nervous function in childhood. Exercise is one of the most common precipitating factors of acute asthmatic crises although the exact mechanism of autonomic regulation in asthmatic children after exercise is unclear. OBJECTIVE The aim of this study was to investigate the features of autonomic regulation after exercise in asthmatic and control children. METHODS Pulmonary function tests and heart rate variability spectral analysis were performed in 15 asthmatic children and 7 control children (age 6 to 15 years) during and after an exercise challenge. RESULTS The maximum % fall of forced expiratory volume in 1 second (FEV1) was significantly greater (P < .01) in asthmatic subjects (9.1 +/- 5.1%) than in normal control subjects (1.0 +/- 2.5%). The high frequency band (HF) amplitude, an index of cardiac vagal tone, 5 minutes after exercise was significantly higher (P < .05) in the asthmatic subjects (14.4 +/- 7.9 msec) than in control subjects (5.9 +/- 2.6 msec). Furthermore, the difference in the HF amplitude between the control group and the exercise-induced asthma group was significant both 5 minutes (P < .01) and 10 minutes (P < .05) after challenge. There was a significant correlation (P = .565, P = .0165) between HF amplitude 5 minutes after exercise and the magnitude of the decrease in FEV1. On the other hand, no significant difference was observed in the low frequency band amplitude between the controls and the asthmatic subjects. The ratio of low frequency to high frequency power, which is suggested to correlate with cardiac sympathetic activity, did not differ between the two groups. CONCLUSION These findings suggest that autonomic nervous activities, particularly vagal response after exercise, in asthmatic children is different from that in control children.

Pulmonary hemosiderosis with hypersensitivity to buckwheat

BACKGROUND Adverse reactions after ingesting buckwheat are known to be IgE-mediated. Further, hypersensitivity reactions may be involved in some patients with pulmonary hemosiderosis related to cow milk sensitivity. We, however, encountered a patient with pulmonary hemosiderosis related to buckwheat protein without high levels of buckwheat-specific IgE antibodies. OBJECTIVE The aim of this study was to investigate the mechanisms. METHODS RAST for anti-buckwheat IgE, skin prick test, skin patch test, and proliferative responses of peripheral blood mononuclear cells to buckwheat were investigated in this patient. RESULTS RAST values for buckwheat protein were negative, and skin prick test for buckwheat protein also gave negative results. On the other hand, skin patch testing for buckwheat protein elicited positive responses. Further, peripheral blood mononuclear cells of our patient responded to buckwheat protein. CONCLUSIONS Our patient had pulmonary hemosiderosis related to non-immediate buckwheat protein hypersensitivity.

METHYLATION PATTERNS OF I ε REGION IN B CELLS STIMULATED WITH INTERLEUKIN 4 AND EPSTEIN-BARR VIRUS IN PATIENTS WITH A HIGH LEVEL OF SERUM IgE

Human IgE synthesis requires the presence of both interleukin 4 (IL‐4) and T‐cells. However, it is not clear what role IL‐4 and T‐cells play in the induction of IgE synthesis at the level of gene regulation. B cells that were obtained from patients with a high level of serum IgE and from healthy donors were immortalized by Epstein‐Barr virus. We examined IgE production of these B cells stimulated with IL‐4. Supernatant IgE levels of patients B cells cultured with or without IL‐4 were higher than those of healthy donors B cells. Our results indicated that B cells stimulated with IL‐4 from patients produced IgE, germline C ε transcript, and S μ S ε recombination. The germline C e transcript was dose‐dependently induced in the presence of IL‐4 and related to the supernatant IgE level. In B cells stimulated with IL‐4 that were obtained from patients, (some of the) DNA near or within the I e region was (already partly) unmethylated, unlike those from healthy donors, and there was a loss of methyl groups of the DNA upon the addition of IL‐4 in B cells from both patients and normal donors. IgE synthesis of B cells stimulated with IL‐4 in patients with a high level of serum IgE is due to an accessibility in the immunoglobulin heavy‐chain isotype switch, and this may reflect the accessibility in synthesis of germline C ε transcript, which may be caused by the increase of opening chromatin structures because of their unmethylation in the I ε region.

Improvement of food‐sensitive atopic dermatitis accompanied by reduced lymphocyte responses to food antigen following natural measles virus infection

Five patients with atopic dermatitis (AD) who were sensitive to hens egg were observed before and after natural measles virus infection. Within 4 weeks of natural measles virus infection, the eczematous lesions clearly improved in four of the five patients in whom neither offending foods were eliminated, nor anti‐allergic drugs, systemic steroids and steroid ointment administered. This was accompanied by reduced proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA). Another patient showed a transient improvement of AD symptoms, from severe to mild, and thereafter returned to severe accompanied by increased proliferative responses of PBMCs to OA. Radioallergosorbent test (RAST) scores for hens egg in all five patients did not change in each level in each patient, except the transiently decreased RAST scores for hens egg in one patient, after the infection. Thus, in patients with AD who are sensitive to food, the improvement of AD symptoms that appeared within 4 weeks of natural measles virus infection was related to reduced proliferative responses of PBMCs to the food antigen following the infection.

Inhibition of proliferative responses of lymphocytes to food antigens by an anti-allergic drug, N(3′,4′-dimethoxycinnamoyl) anthranilic acid (Tranilast) in children with atopic dermatitis

Experimental studies have shown that N(3′, 4′‐dimethoxycinnamoyl) anthranilic acid (Tranilast) inhibits reaginic antibody‐mediated hypersensitivity reactions, and it has been demonstrated to be an effective drug for patients with bronchial asthma. On the other hand, from the nature of the cellular infiltrate seen in eczematous lesions, it appears that some form of cell‐mediated immunity may be involved in addition to IgE‐mediated immunity in the pathogenesis of atopic dermatitis (AD). Moreover, we have previously reported that the proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA) or bovine serum albumin (BSA) in children with AD who are sensitive to hens egg or cows milk were significantly higher than those of healthy children and hens egg or cows milk sensitive children with immediate symptoms.