IL-4 and interferon-gamma production in children with atopic disease

T cell cytokine profiles in childhood asthma

BACKGROUND

An imbalance of T cell subsets in asthma with a predominance of Th2 type cells has been proposed. The aim of this study was simultaneously to detect surface markers and intracellular production of cytokines in T cells from the airways of children with and without asthma.

METHODS

Bronchoalveolar lavage (BAL) fluid was obtained by wedging a suction catheter into the distal airway immediately before elective surgery. Cells were stimulated with phorbol 12-myristrate 13-acetate (PMA) and ionomycin and intracytoplasmic cytokine retention was achieved using monensin. The cells were stained with the relevant antibodies and analysed by flow cytometry.

RESULTS

No statistical difference was observed between children with atopic asthma, atopic non-asthmatic subjects, and normal controls in the percentage of CD3+ cells producing interleukin (IL)-2 or IL-4. Interferon (IFN)gamma+ T cells were, however, present in a much higher percentage than either IL-2 or IL-4 positive cells. The percentage of IFNgamma+ T cells was significantly increased in subjects with atopic asthma (median 71.3%, interquartile range (IQR) 65.1-82.2, n=13) compared with both atopic non-asthmatic subjects (51.9%, IQR 37.2-70.3, n=12), p<0.05 and normal controls (58.1%, IQR 36.1-66.1, n=23), p<0.01.

CONCLUSIONS

These findings indicate that IFNgamma producing T cells are more abundant in the airways of children with atopic asthma than in atopic non-asthmatic subjects and controls. The proinflammatory activities of IFNgamma may play an important role in the pathogenesis of childhood asthma and may suggest that asthma is not simply a Th2 driven response.

Altered intracellular expression of the chemokines MIP-1alpha, MIP-1beta and IL-8 by peripheral blood CD4+ and CD8+ T cells in mild allergic asthma

BACKGROUND

The ability of chemokines to regulate Th1 and Th2 responses suggests a role in the pathogenesis of atopic disorders such as allergic asthma where Th2 response dominance has been observed. Although the impact of allergic asthma on local chemokine production in the lung has been the subject of investigation, little is know about the influence of disease progression on peripheral chemokine production. We now report use of whole blood culture and flow cytometry to assess the influence of mild allergic asthma on peripheral T-cell chemokine expression.

METHODS

Study participants included patients with mild allergic asthma (n = 7) and nonasthmatic controls (n = 7). Following in vitro stimulation of peripheral venous blood with phorbol 12-myristate acetate (PMA) and ionomycin, flow cytometry was used to estimate the percentage of CD4+ and CD8+ T cells producing a number of chemokines, including macrophage inflammatory proteins MIP-1alpha and MIP-1beta, RANTES (regulated on activation, T-cell expressed and secreted), monocytic chemotactic protein-1 (MCP)-1, and interleukin (IL)-8, or the cytokines interferon (IFN)-gamma and IL-4. Serum levels of MIP-1alpha, MIP-1beta, RANTES, MCP-1, IL-8, IFN-gamma and IL-4 were also assessed by quantitative ELISA.

RESULTS

Intracellular expression of MIP-1beta by CD4+ and CD8+ T cells from allergic asthmatics was significantly reduced in comparison to that observed for nonasthmatics (median = 2.29% (1.75-3.50) vs 4.57% (3.38-6.64), P = 0.05; 14.20% (13.18-17.88) vs 44.10% (30.38-48.70), P = 0.01). Similarly, intracellular expression of MIP-1alpha by CD8+ T cells from allergic asthmatics was also significantly lower (3.67% (1.17-5.42) vs 17.10% (4.97-20.43), P = 0.05). Conversely, IL-8 expression by both CD4+ and CD8+ T cells from allergic asthmatics demonstrated significant enhancement (9.93% (7.77-11.28) vs 4.14% (3.61-7.11), P = 0.05; 8.40% (6.97-10.04) vs 4.98% (3.37-6.08), P = 0.05). Examination of intracellular IFN-gamma and IL-4 revealed no significant difference in the expression of either cytokine by CD4+ T-cells from allergic asthmatics and nonasthmatics. In contrast, expression of IFN-gamma was significantly reduced in CD8+ T-cells from allergic asthmatics (24.60% (21.08-32.50) vs 48.40% (41.50-55.28), P = 0.01).

CONCLUSIONS

The occurrence in mild allergic asthma of peripheral T-cell chemokine expression suggestive of a diminished Th1 response, coinciding with marginal change in cytokine profiles indicative of a Th2 response bias, confirms the importance of chemokine involvement in the etiology of allergic asthma. The ability to use whole blood culture to estimate chemokine expression in T cell subsets may ultimately provide a practical means to evaluate disease status and to monitor early intervention therapies which target chemokines.

Decreased frequency of intracellular IFN-gamma producing T cells in whole blood preparations from patients with atopic dermatitis

There have been contradictory reports on the shift in the T-cell cytokine expression pattern of peripheral blood mononuclear cells from patients with atopic dermatitis (AD); more specifically the interleukin (IL)-4 and interferon (IFN)-gamma profiles. The aim of this study was to shed further light on this contradiction by measuring the intracellular cytokines IL-4 and IFN-gamma by flow cytometry on unseparated whole blood to obtain results that, as accurately as possible, reflect the situation in circulating cells in vivo. The patient group including 64 patients with AD was compared with 18 nonatopic healthy adults. The results showed that the percentage of CD4+ T cells expressing IFN-gamma was significantly decreased (P < or = 0.001), as well as the percentage expressing IL-4 (P < 0.05) in AD patients compared with healthy controls. Furthermore, in supernatants from whole blood samples stimulated with phorbol 12-myristate 13-acetate and ionomycin, production of IFN-gamma was significantly decreased, while IL-4 production remained unchanged in AD patients compared with healthy controls. We also investigated if there was a relationship between serum IgE level and Phadiatop, a screening test for atopy, vs. the levels of IL-4 and IFN-gamma, but found no correlation with either. However, there was a significant correlation between disease severity and the level of total IgE (r = 0.67, P < 0.05). In conclusion, our results support the evidence for a decreased ability of peripheral CD4+ T cells to produce IFN-gamma among AD patients.

Increased frequency of intracellular interleukin (IL)-13 and IL-10, but not IL-4, expressing CD4+ and CD8+ peripheral T cells of patients with atopic dermatitis

BACKGROUND

A number of studies exist demonstrating the increased expression of type 2 cytokines and decreased capacity to produce interferon-gamma (IFN-gamma) in peripheral blood mononuclear cells (PBMCs) of patients with atopic dermatitis (AD).

OBJECTIVES

To clarify the results of recent studies concerning the role of interleukin (IL)-4 and IL-13 in PBMCs of AD patients, we analysed the activation status of lymphocyte subpopulations.

METHODS

We measured the intracellular expression and serum levels of certain type 1 and type 2 cytokines, using cell surface and intracellular cytokine staining, flow cytometry and enzyme-linked immunosorbent assay techniques.

RESULTS

The frequency of IL-10 and IL-13 producing CD4+ and CD8+ T cells was significantly higher in patients with AD, while the frequency of IFN-gamma secreting helper and cytotoxic T cells was significantly lower in patients with AD than in control subjects. The serum levels of IL-10 and IL-13 were also significantly increased. There were no significant differences observed between the experimental groups in the frequency of IL-4 producing CD4+ and CD8+ cells.

CONCLUSIONS

This study demonstrates a type 2 cytokine production in the CD4+ and CD8+ T cells of AD patients, which is characterized by an elevated IL-13, but not by IL-4 secretion, and by an increased level of the immunoregulatory IL-10, which can contribute to a decrease in IFN-gamma expression.

Effects of dietary yoghurt on immunological and clinical parameters of rhinopathic patients

OBJECTIVES

To examine the immunological and clinical influence of 4 months' feeding with either yoghurt or partially skimmed milk or nothing, on 20 volunteers.

SUBJECTS

Thirteen subjects had a demonstrated allergic rhinopathy and seven were healthy subjects and participated as controls.

RESEARCH DESIGN

Either a group of seven or a group of six rhinopathic patients were fed either 450 g yoghurt or 450 g partially skimmed milk, respectively, for 4 months between March and October 1999. All subjects maintained their usual diet throughout the study. Peripheral blood mononuclear cells (PBMC) were isolated before and after the experimental period and cultured for periods of 40 and 64 h. Proliferation index assay and release of IFNgamma and IL-4 without and with PHA stimulation were assessed. Allergic rhinopathy was evaluated before and after the 4 months period by performing the nasal functionality tests (Active Anterior Rhinomanometry, Acoustic Rhinometry), the prick test, the nasal specific provocation test (NPT), the dosage of specific IgE blood levels, the evaluation of the symptomatological score and the nasal mucociliary transport test.

RESULTS

No significant change of the proliferation index was noted among the three groups. Cultured PBMC of the group fed with yoghurt released more IFNgamma and less IL-4. Cytokine plasma levels were at and remained at basal levels. Prick test, specific serum IgEs and NPT remained immodified. Muco-ciliary transport time (MCTt) and symptomatological score showed a definitive improvement after yoghurt feeding.

CONCLUSION

Yoghurt feeding appears to improve or prevent allergic recurrences in rhinopatic patients.

Influence of different dosage schedules of inhaled fluticasone propionate on peripheral blood cytokine concentrations in childhood asthma

BACKGROUND

Asthma is characterized by eosinophilic airways inflammation with elevated levels of IL-4, IL-5 and sICAM-1, and reduced levels of IL-10 and IFN-gamma. Inhaled corticosteroids powerfully reduce airways inflammation.

OBJECTIVE

To investigate if eosinophil counts, serum eosinophilic cationic protein (ECP) and sICAM-1 levels, as well as serum and production of cytokines (IL-4, IL-5, IL-10, IFN-gamma) by peripheral blood monocytes (PBMCs) are useful markers to monitor therapy with inhaled fluticasone propionate (FP) in asthmatic children.

METHODS

In a double-blind, 1-year study, 55 asthmatic children (aged 6-10 years) stopped inhaled corticosteroids for a mean period of 24 days and were randomized to receive either FP 200 microg/day (constant dose group), or a starting dose of FP 1000 microg/day with two monthly reductions to 500, 200 and 100 microg/day (stepdown group). Hyper-responsiveness, symptom scores and blood sampling were performed at 2-month intervals.

RESULTS

Symptoms and hyper-responsiveness improved significantly in both treatment groups after reintroduction of FP. Eosinophil counts decreased significantly more during the first 2 months of FP in the stepdown group than in the constant dose group (P = 0.03). We found a trend towards a dose-dependent response in changes of eosinophil counts and serum ECP levels during treatment. Serum IL-4 and IL-5 levels were undetectable in the majority of children. No significant effect of the dose of FP on the release of IL-4, IL-5, IL-10 or IFN-gamma by Con A stimulated PBMCs was found. sICAM-1 levels did not significantly differ at any time point between the two groups.

CONCLUSION

Serum ECP as well as peripheral blood eosinophils, cytokine production by PBMCs and sICAM-1 levels are insensitive markers in titrating and monitoring therapy with inhaled corticosteroids over a wide dose range in childhood asthma.

Low frequency of CD4+, but not CD8+, T cells expressing interferon-gamma is related to cow's milk allergy in infancy

Low interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) production in peripheral blood mononuclear cells (PBMC) from patients with atopic dermatitis and food allergy have been reported previously. However, it remains unclear whether the weak cytokine production is caused by the imbalance of specific T-cell subsets or by dysregulation of T-cell function. In the present study we investigated the intracellular expression of these cytokines at a single-cell level to clarify the background of the disruption. Twelve of 27 breast-fed infants (0.1-8.8 months of age) had challenge-proven cow's milk allergy (CMA), and 15 infants were studied as a healthy control group. PBMC were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin. The frequencies of the cells expressing intracellular IL-4, IFN-gamma, and TNF-alpha were assessed using flow cytometry. In addition, at this time-point leucocyte subsets from the milk of mothers of these infants were evaluated using light microscopy. A lower number of CD8+ T cells and the defective capability of CD4+ T cells to express IFN-gamma in infant's peripheral blood co-existed with a lower number of macrophages in their mother's milk.

Increased Th1 and Th2 allergen-induced cytokine responses in children with atopic disease

BACKGROUND

Polyclonal cytokine responses following stimulation of T cells with mitogens or superantigens provides information on cytokine production from a wide range of T cells. Alternatively allergen-induced T cell responses can provide information on cytokine production by allergen-reactive T cells. While there is evidence of increased Th2 and reduced Th1 cytokine production following T cell stimulation with non-specific mitogens and superantigens, the evidence that Th1 cytokine production to allergens is decreased in line with a postulated imbalance in Th1/Th2 responses is unclear, with studies finding decreased, no difference or increased IFN-gamma responses to allergens in atopic subjects.

OBJECTIVE

To examine childhood polyclonal and allergen-induced cytokine responses in parallel to evaluate cytokine imbalances in childhood atopic disease.

METHODS

PBMC cytokine responses were examined in response to a polyclonal stimulus, staphylococcal superantigen (SEB), in parallel with two inhalant allergens, house dust mite (HDM) and rye grass pollen (RYE), and an ingested allergen, ovalbumin (OVA), in (a) 35 healthy children (non-atopic) and (b) 36 children with atopic disease (asthma, eczema and/or rhinitis) (atopic).

RESULTS

Atopic children had significantly reduced IFN-gamma and increased IL-4 and IL-5 but not IL13 production to SEB superantigen stimulation when compared with non-atopic children. HDM and RYE allergens stimulated significantly increased IFN-gamma, IL-5 and IL-13, while OVA stimulated significantly increased IFN-gamma production in atopic children.

CONCLUSION

We show that a polyclonal stimulus induces a reduced Th1 (IFN-gamma) and increased Th2 (IL-4 and IL-5) cytokine pattern. In contrast, the allergen-induced cytokine responses in atopic children were associated with both increased Th1 (INF-gamma) and Th2 (IL-5 and IL-13) cytokine production. The increased Th1 response to allergen is likely to reflect prior sensitization and indicates that increases in both Th1 and Th2 cytokine production to allergens exists concomitantly with a decreased Th1 response to a polyclonal stimulus in atopic children.

Increased interleukin-4 and decreased interferon gamma production in children with asthma: function of atopy or asthma?

Both atopy and asthma are claimed to be associated with a Th-2 cytokine pattern. We sought to determine the contribution of atopy and asthma to the observed Th-2/Th-1 imbalance in these conditions. Of 60 children aged 6-16 years that were included in the study, 13 were nonatopic nonasthmatic, 15 atopic nonasthmatic, 14 nonatopic asthmatic, and 18 atopic asthmatic. Atopic children had positive skin prick tests to grass pollens only. All children were studied after an asymptomatic and drug-free period of at least three months. Total IgE was measured in serum. Peripheral blood mononuclear cells were cultured and stimulated in vitro with phytohemagglutinin and interferongamma (IFN-gamma) and interleukin-4 (IL-4) measured in the supernatants. Total IgE was significantly higher in atopic asthmatics compared to nonatopic asthmatics (p = 0.004), and nonatopic nonasthmatics (p = 0.001), but was not different from atopic nonasthmatics (p >0.05). On the other hand, IL-4 was significantly elevated in atopic asthmatics and in nonatopic asthmatics compared to nonatopic nonasthmatics (p = 0.037 and p = 0.009, respectively). Although atopic asthmatics had lower IFN-gamma values than nonatopic asthmatics, the difference did not reach statistical significance. No correlation was detected between any two parameters. Our results suggest that both atopy and asthma contribute to the increased levels of IL-4 and that, whereas nonatopic asthma is associated with increases in both IL-4 and IFN-gamma release by mononuclear cells, only atopic asthma is characterized by a Th-2 type cytokine dominance.

Expression of T helper 1 and T helper 2 cytokine mRNAs in freshly isolated peripheral blood mononuclear cells from dogs with atopic dermatitis

Using reverse transcription-polymerase chain reaction (RT-PCR) and semi-quantitative PCR techniques, mRNA expression for canine interferon (IFN)-gamma, interleukin (IL)-4, IL-5 and IL-10 in freshly isolated peripheral blood mononuclear cells (PBMCs) was examined in dogs with or without atopic dermatitis (AD). The expression of IFN-gamma mRNA in dogs with AD was lower than that in dogs without AD (healthy control). The expression of IL-5 mRNA was higher in dogs with AD than in control dogs, but there were no significant differences in IL-4 mRNA and IL-10 mRNA expression between the groups. The number of circulating eosinophils was higher in dogs with AD than in control dogs, although eosinophilia was found in only one dog with AD. These results suggest that there is a tendency for the PBMCs of atopic dogs to express a type 2 cytokine pattern that is similar to the pattern observed in human AD patients.

Intravenous immune globulin effects on serum-soluble CD5 levels in atopic dermatitis

BACKGROUND

Intravenous immune globulin (IVIG) therapy has been tried in the treatment of atopic dermatitis. Recently, the presence of serum-soluble CD5 (ssCD5) in atopic dermatitis was reported.

OBJECTIVE

IVIG effects on ssCD5 levels in atopic dermatitis were examined and the correlation of ssCD5 level changes with clinical and laboratory parameters were investigated.

METHODS

IVIG therapy was tried on 40 atopic dermatitis and 17 recurrent spontaneous abortion patients. Five atopic dermatitis patients received normal saline as a placebo control group. The clinical and laboratory parameters were evaluated on day 0, 1, 7 and 21 after administering the IVIG therapy.

RESULTS

With IVIG therapy, in atopic dermatitis, the ssCD5 level was 5.5 +/- 6.2 ng/mL before infusion (day 0), 15.2 +/- 12.1 ng/mL on day 1, 13.8 +/- 14.1 ng/mL on day 7, and 3.9 +/- 4.1 ng/mL on day 21. The clinical severity score was 350.5 +/- 120.3 on day 0, 420.4 +/- 174.8 on day 1, 250.0 +/- 121.2 on day 7, and 115.5 +/- 53.9 on day 21. White blood cell (WBC) counts and serum IgE levels showed a gradual decrease with IVIG infusions. Blood eosinophil fractions were 5.3 +/- 2.8% on day 0, 8.6 +/- 5.2% on day 1, 7.3 +/- 3.7% on day 7, and 6.8 +/- 4.0% on day 21. Changes in the total eosinophil count were insignificantly parallel with those of blood eosinophil fractions

CONCLUSION

In atopic dermatitis, IVIG therapy increased the ssCD5 levels. Further studies concerning the exact role of ssCD5 are needed.

Interferon-gamma secretion of peripheral blood CD8+ T lymphocytes in patients with bronchial asthma: in vitro stimulus determines cytokine production

It has been postulated that T lymphocytes orchestrate the chronic inflammation in bronchial asthma. In animal models, infiltration of CD8+ T lymphocytes into the bronchial mucosa prevented bronchial hyperresponsiveness and decreased early and late phase reaction. IFN-gamma antagonizes IL-4-dependent IgE production as well as IL-5-induced proliferation and activation of eosinophils. We therefore investigated the secretion of IFN-gamma of isolated CD8+ T lymphocytes from peripheral blood of patients with allergic asthma (n = 6) and from healthy controls (n = 7) in vitro. In this setting we compared the effect of stimulation with anti-CD3 antibodies with that of phorbol myristate acetate (PMA) and calcium-ionophore. As expected, CD8+ T lymphocytes from peripheral blood of healthy volunteers produced significantly more IFN-gamma in the presence of PMA and calcium-ionophore than after stimulation with anti-CD3 antibodies. However, in subjects with allergic asthma, IFN-gamma secretion of CD8+ T cells was significantly higher when incubated with anti-CD3 antibodies than after activation with PMA and calcium-ionophore. While IFN-gamma secretion of CD8+ T lymphocytes of patients with allergic asthma was lower than that of healthy controls in the presence of PMA/calcium-ionophore, it was significantly elevated when compared with normal controls after stimulation with anti-CD3 antibodies. Thus, potent activators of cytokine secretion, such as PMA and calcium-ionophore, induce a cytokine profile different from that induced by weaker stimulants, such as anti-CD3 antibodies. These findings have implications for further studies investigating cytokine production of inflammatory cells in vitro.

Low-dose cyclosporin A microemulsion in children with severe atopic dermatitis: clinical and immunological effects

Cyclosporin A (CsA) is an effective and well-tolerated treatment for severe childhood atopic dermatitis (AD). By starting at a low dose, the therapeutic safety should be further increased. The aim of this study was to evaluate low-dose CsA in childhood AD with respect to clinical outcome and modulation of T-cell dysregulation. In an open prospective study, 10 children (age: 22-106 months) with severe AD (mean objective SCORAD score > 40 on two baseline measurements at a minimum interval of 2 weeks) were treated with CsA solution for 8 weeks. All patients received a starting dose of 2.5 mg/kg/day, which was increased stepwise in non-responders to a maximum of dose of 5 mg/kg/day. Disease activity was monitored using the SCORAD index. The frequency of cytokine-producing peripheral blood T lymphocytes was analyzed by intracellular cytokine staining, and T-cell numbers were measured by fluorescence-activated cell sorter (FACS) analysis. Twenty healthy age-matched children were included as controls for the immunological data. Nine of the 10 patients had a SCORAD reduction of at least 35%. In seven patients this was achieved with low-dose CsA at 2.5 mg/kg/day (n = 4) and 3.5 mg kg/day (n = 3). Seven of the nine responders experienced no relapse within the 4-week follow-up period. At baseline the percentage of interleukin-4 (IL-4), IL-13, and human leucocyte antigen (HLA)-DR-positive CD3(+) cells was higher in the patient group than in the controls. After CsA treatment there was a significant reduction in interferon-gamma (IFN-gamma), IL-2, IL-4, IL-13, and HLA-DR-positive CD3(+) cells. Hence, in severe pediatric AD, CsA microemulsion, when started at a low dose (2.5 mg/kg/day), improves clinical measures of disease, reduces T-lymphocyte cytokine production, and regulates T-cell activation.

Ontogeny of T-helper 1 and T-helper 2 cytokine production in childhood

Compared to adults, infants and young children demonstrate differences in their immune response, indicating that there is maturation or change over time and it is probable that this may be reflected in cytokine production. Cytokine responses have been demonstrated to be different in atopic and non-atopic individuals. In this study, we examined T-helper 1 (Th1) (interferon-gamma [IFN-gamma]) and T-helper 2 (Th2) (interleukin [IL]-4, IL-5, and IL-13) cytokine release from atopic and non-atopic children in response to the staphylococcal superantigen, staphylococcal enterotoxin B (SEB). In non-atopic and atopic children, IFN-gamma, IL-4, and IL-5 release was significantly related to age. Non-atopic children younger than 2 years of age were found to have significantly reduced Th2 (IL-4, IL-5, and IL-13) responses when compared with older, non-atopic children. Atopic children had a reduced IFN-gamma response when compared with non-atopics in early childhood; however, the decreased IFN-gamma response seen in early childhood did not persist after 10 years. These age-related changes in cytokine production provide further support for the concept that cytokine deviations may determine the natural history of atopic disease during early childhood. In addition, the present study indicates the necessity of age-matched controls when examining children for both Th1 (IFN-gamma) and Th2 (IL-4) cytokine release.

The -590C/T and -34C/T interleukin-4 promoter polymorphisms are not associated with atopic eczema in childhood

Susceptibility to the development of asthma and other atopic diseases is known to have a genetic component. To date, several studies have linked chromosome 5q31 to asthma and atopy in human beings. This region harbors a cluster of cytokine and growth factor genes, IL-4 presenting as a prime atopy candidate gene, inasmuch as it plays a pivotal role in the atopy pathway. Our approach was to identify polymorphisms within the promoter regions of IL-4 and test their association with atopic eczema. Polymorphisms were typed in a cohort of 76 small nuclear families and 25 triads with childhood atopic eczema. The genotypes were used to test for linkage in the presence of association with atopic eczema. A new polymorphism, -34C/T, was identified and studied with a known polymorphism, -590C/T. On its own, each polymorphism showed no association with atopic eczema. The 2 polymorphisms were used to generate haplotypes, and a significant result was found for the -590C/-34C haplotype. However, after Bonferroni correction for multiple testing, the association became nonsignificant. Neither polymorphism predisposes to early-onset atopic eczema by itself, but suggestive linkage was found for the -590C/-34C haplotype in this study.

IFN-gamma production in response to IL-18 or IL-12 stimulation by peripheral blood mononuclear cells of atopic patients

BACKGROUND

Several studies have shown that interleukin (IL)-4 and interferon-gamma (IFN-gamma) are important for the regulation of immunoglobulin E (IgE) production and that IL-18 and IL-12 induce IFN-gamma.

OBJECTIVE

IFN-gamma production in response to IL-18 or IL-12 stimulation was investigated in peripheral blood mononuclear cells (PBMCs) of atopic patients with various levels of serum IgE.

METHODS

Cytokine production from PBMCs was measured following stimulation with a non-specific stimulator (phytohemagglutinin: PHA), IL-18 or IL-12 in 12 healthy controls and 26 atopic patients with various serum IgE levels.

RESULTS

IFN-gamma production by IL-18-stimulated PBMCs was positively correlated with IFN-gamma production by IL-12-stimulated PBMCs (P < 0.05). However some atopic patients showed discrepancy between the levels of IFN-gamma production stimulated by IL-12 and by IL-18.

CONCLUSIONS

The results shown here suggest the presence of abnormalities in the IL-12 and/or IL-18 signalling pathways, such as genetic defects in the atopic patients.

Association of IFN-gamma and IFN regulatory factor 1 polymorphisms with childhood atopic asthma

BACKGROUND

IFN-gamma and related molecules play important roles in the differentiation and function of TH2 cells.

OBJECTIVE

We sought to determine whether IFNG and related genes contribute to any susceptibility to atopic asthma, a representative TH2-dominant disorder.

METHODS

We investigated the association of IFNG (CA repeat polymorphism within the first intron), IRF1 (GT repeat polymorphism within the intron 7), IFNGR1 (Val 14 Met), and IFNGR2 (Gln 64 Arg) gene polymorphisms with atopic asthma in the Japanese child population.

RESULTS

A significant association (P =.0018) was observed between IFNG gene polymorphism and atopic asthma. The tendency was more prominent in patients with age of onset of 3 years or younger (P =.0004) or patients with a family history of allergic diseases (P =.0038). Furthermore, there was a significant association between IRF1 gene whole-allele distribution and atopic asthma (P =.044). The tendency was more prominent in patients with onset at 3 years of age or less (P =.0058). On the other hand, IFNGR1 and IFNGR2 gene polymorphisms showed no association with atopic asthma.

CONCLUSION

These results suggested that among IFNG and related genes, IFNG and IRF1 genes confer genetic susceptibility to atopic asthma in Japanese children.

A rapid flow cytometric assay to detect CD4+ and CD8+ T-helper (Th) 0, Th1 and Th2 cells in whole blood and its application to study cytokine levels in atopic dermatitis before and after cyclosporin therapy

BACKGROUND

The immune response in atopic dermatitis (AD) is thought to be driven by T-helper (Th) 2 cytokines. Using flow cytometry, higher frequencies of peripheral blood CD4+ and CD8+ T cells producing interleukin (IL)-4 and correspondingly lower frequencies of CD4+ T cells producing interferon (IFN)-gamma have been found in patients with AD compared with healthy controls. It would be of interest to know whether other Th1 and Th2 cytokines such as IL-5, IL-13 and tumour necrosis factor (TNF)-alpha are similarly skewed in patients with AD and whether this immune skewing, detected via a simple blood assay, can be correlated with other clinical measurements or treatments in AD.

OBJECTIVES

To use a rapid (4-h) flow cytometric assay to study a wide range of Th1 and Th2 cytokine patterns in peripheral blood lymphocytes from patients with AD, comparing them with non-atopic healthy controls. To correlate cytokine patterns with the degree of eosinophilia observed and in the case of one patient with severe disease, to observe the effect of cyclosporin therapy on peripheral blood cytokine patterns.

METHODS

Peripheral blood from eight patients with AD and 23 healthy controls was examined for the frequencies of CD4+ and CD8+ T cells expressing IL-2, IL-4, IL-5, IL-13, IFN-gamma and TNF-alpha using flow cytometry.

RESULTS

Significantly higher frequencies of CD4+/IL-4+ (P < 0.005) and CD4+/IL-13+ (P < 0.0001) and lower frequencies of CD4+/IFN-gamma+ (P < 0.002) and CD8+/TNF-alpha+ (P < 0.05) T lymphocytes were found in patients with AD compared with controls. There were significant positive correlations with the increased percentages of CD4+/IL-4+ and CD4+/IL-13+ T lymphocytes and the degree of eosinophilia observed (P < 0.05, P < 0.001) and a negative correlation between the percentage of CD4+/IFN-gamma+ T lymphocytes and eosinophilia (P < 0.05). In one patient examined before and 8 days after cyclosporin therapy, 50% or greater reductions were observed in percentages of peripheral blood CD8+/IL-5+, CD8+/IL-13+, CD4+/IL-4+ and CD4+/IL-5+ T lymphocytes following cyclosporin therapy. A smaller reduction of 15% after cyclosporin therapy was found in percentages of CD4+/IL-13+ T cells.

CONCLUSIONS

These data strongly support a Th2 predominance in the peripheral blood of AD. The results suggest that administration of cyclosporin therapy in patients with AD may help to restore the Th2 cytokine imbalance seen in these patients.

Detergents in the indoor environment - what is the evidence for an allergy promoting effect? Known and postulated mechanisms

IgE-mediated allergic diseases, such as asthma and rhinitis seem to be increasing in industrialised societies. One possible explanation for this could be the increased use of more effective and aggressive detergents. The surfactants from these could interfere with the sensitisation process in which specific IgE is formed to ubiquitously occurring environmental allergens. Only sparse data exist in relation to surfactants and allergic sensitization. However, it can be speculated that the strong surfactant properties of some of ingredients used in modem detergents may interfere with some of the intricate cellular interactions taking place along the immunological pathways. These include formation of IL-4 and IL-5 producing T helper lymphocytes type 2 and the B-lymphocyte isotype switch, which leads to production of specific IgE. Candidates for experimental studies of such phenomena on the cellular level are proposed.

Reduced IFNgamma production in response to IL-12 stimulation and/or reduced IL-12 production in atopic patients

BACKGROUND

Several studies have shown that interleukin (IL)-4 and interferon-gamma (IFNgamma) are important for the regulation of IgE production and that IL-12 induces IFNgamma.

OBJECTIVE

IFNgamma production in response to IL-12 stimulation and IL-12 production were investigated in peripheral blood mononuclear cells (PBMCs) of atopic patients with various levels of serum IgE.

METHODS

Cytokine production from PBMCs was measured following stimulation with a nonspecific stimulator (phytohemagglutinin: PHA), a specific stimulator (Der f 1) and IL-12 in 17 healthy controls and 23 atopic patients with various serum IgE levels.

RESULTS

The IFNgamma production by IL-12-stimulated PBMCs in the atopic group was lower than that in the control group. Furthermore, the serum IgE level was negatively correlated with IFNgamma production by PBMCs stimulated with IL-12 (P < 0.001), and with IL-12 production by PBMCs stimulated with Der f 1 (P < 0.001). Although the IFNgamma concentrations by PHA-stimulated PBMCs were correlated with those by IL-12-stimulated PBMCs, there were differences in several patients.

CONCLUSIONS

Our results indicated that atopic patients may have some abnormality in the IL-12-IFNgamma loop. It was shown that the elevation in IgE levels in atopic patients may be due to reduced IFNgamma production in response to IL-12 stimulation and/or due to reduced IL-12 production.

Enhanced cytokine generation by peripheral blood mononuclear cells in allergic and asthma subjects

BACKGROUND

Although preferential expression of the Th2 cytokines, IL-4 and IL-5, has been described in atopic asthma, the role of IFN-gamma and IL-10 are less clear.

OBJECTIVE

To determine the cytokine pattern of T cell mitogen-induced peripheral blood mononuclear cells obtained from atopic asthmatic (AA) subjects.

METHODS

Peripheral blood mononuclear cells obtained from AA (n = 24), allergic rhinitis (AR) (n = 9), and normals (NL) (n = 9) were stimulated with phytohemagglutinin (PHA) and the generation of IL-4, IL-5, IFN-gamma, IL-10, and GM-CSF was quantified using ELISA.

RESULTS

Compared with NL subjects, peripheral blood mononuclear cells from the atopic groups had increased generation of both IL-5 (AA, P = .001 and AR, P = .024) and IFN-gamma (AA, P = .037 and AR, P = .048) and decreased generation of IL-10 (AA, P = .038 and AR, P = .036). The absolute levels of cytokines did not differ between the two atopic groups; however, the ratio of IL-5/IL-10 was significantly higher in AA (P < .05), but not in AR when compared with NL subjects.

CONCLUSION

The concomitant increase in the generation of IL-5 and IFN-gamma, with a decrease in IL-10 in the atopic groups suggests that in, at least a subset of these patients, there is potential expression of both Th2- and Th1-type cytokines. Furthermore, the increased IL-5 to IL-10 ratio could represent a key feature that distinguishes atopic asthmatic from non-asthmatic atopic subjects.

Expression of and responses to CD2 and CD3 in 18-month-old children with and without atopic dermatitis

We hypothesize that atopy is associated with a reduced T-cell function early in life and an imbalance in cytokine production. The purpose of this study was to investigate the expression of and responses to CD2 and CD3 in children who did or did not develop atopic dermatitis early in life. The expression of CD2 and CD3 was analyzed by flow cytometry, and proliferation of CD2 and CD3 was studied by 3H-thymidine incorporation in phytohaemagglutinin (PHA)- and anti-CD3-stimulated peripheral blood mononuclear cells (PBMC) of 18-month-old children, 25 with and 29 without atopic dermatitis. Exogenous interleukin (IL)-2 was added to compensate for possible functional differences in accessory cells. Anti-CD3-induced secretion of IL-4, IL-5, IL-6, IL-10, IL-13, and interferon-gamma (IFN-gamma) was analyzed by enzyme-linked immunosorbent assay (ELISA). Atopy was associated with a low proportion of CD2+ lymphocytes. Responsiveness to PHA, which activates lymphocytes partly via the sheep erythrocyte receptor, CD2, was reduced in the allergic children. The anti-CD3-induced proliferation declined more rapidly with antibody dilution in the allergic than in the non-allergic children. Atopic dermatitis was associated with high levels of anti-CD3-stimulated IL-5 secretion. The IL-4/IL-10 and IL-4/ITFN-gamma ratios were higher in children with elevated total immunoglobulin E (IgE) levels. Skin prick test-negative children with eczema produced higher levels of IL-10 than skin prick test-positive children. In conclusion, atopic children have a reduced T-cell function. Atopic dermatitis is associated with increased IL-5 production, while high total IgE levels are associated with high IL-4/IFN-gamma and IL-4/IL-10 ratios.

Reduced IL-2 but elevated IL-4, IL-6, and IgE serum levels in patients with cerebral infarction during the acute stage

Cytokines in the central nervous system (CNS) may play an important role in functioning as intercellular signals that orchestrate the response to injury. Whether this is a cause or result of the brain disease process is uncertain. We investigated IFN-gamma, IL-2, IL-4, IL-6, and IgE in the sera of 38 patients with cerebral infarction during the acute stage and 10 normal controls using an originally devised sensitive sandwich enzyme-linked immunosorbent assay (ELISA). We found that serum levels of IL-2 derived from T helper 1 (Th1) cells were slightly reduced in patients with cerebral infarction, whereas serum levels of IL-4 and IL-6 derived from Th2 cells were elevated significantly. IL-4 induces synthesis of IgE in human B cells. Endogenous IL-6 plays an obligatory role in IL-4-dependent human IgE synthesis. We observed that serum IgE levels were elevated significantly in patients with cerebral infarction. However, serum IFN-gamma levels were not elevated significantly in cerebral infarction patients. These findings suggest that elevated IL-4, IL-6, and IgE levels in the human serum may be an important factor in cerebral infarction during the acute stage. Decrease of IL-2 levels in the serum of patients with cerebral infarction may be a regulatory mechanism.

IL-4 production by PBMCs on stimulation with mite allergen is correlated with the level of serum IgE antibody against mite in children with bronchial asthma

BACKGROUND

Although IL-4, IL-13, and IFN-gamma are known to affect IgE synthesis, it remains unclear which one plays the most important role in in vivo IgE synthesis in atopic patients.

OBJECTIVE

The aim of this study is to clarify the difference in importance among these cytokines in up-regulation of IgE synthesis in atopic patients.

METHODS

We measured IL-4, IL-13, and IFN-gamma production by PBMCs on stimulation with house dust mite (HDM) in 23 children, 3 to 15 years old, with bronchial asthma (BA) and analyzed the correlation with HDM-specific IgE antibody levels expressed as HDM IgE radioallergosorbent test (RAST) results.

RESULTS

The production of IL-4 and IL-13 by PBMCs on stimulation with HDM was significantly higher in children with BA than in nonatopic control subjects (IL-4, 752.9 +/- 365.9 vs 312.3 +/- 230.0 fg/mL, P <.001; IL-13, 21.9 pg/ml [<12.0-77.6] vs <12.0, P <.01). IL-4 production showed a close positive correlation with HDM IgE RAST (r = 0.71, P <.001), which was distinctly stronger than that between IL-13 production and HDM IgE RAST (r = 0.46, P <.05). IFN-gamma production was neither different between children with BA and nonatopic control subjects (7. 24 [1.54-33.90] pg/mL vs 11.2 [1.66-75.9] pg/mL) nor correlated with HDM IgE RAST levels. Essentially the same result was obtained by stimulation of PBMCs with a purified HDM major allergen Der f 1.

CONCLUSION

IL-4 is likely to be the most important cytokine in up-regulation of in vivo IgE synthesis against HDM in children with BA.

Low levels of interferon-gamma in nasal fluid accompany raised levels of T-helper 2 cytokines in children with ongoing allergic rhinitis

The T-helper 2 (Th2) cytokines interleukin-(IL-) 4, IL-5, IL-6, IL-10 and the Th1 cytokine IFN-gamma and their associations with eosinophil, eosinophil cationic protein (ECP) and immunoglobulin (Ig) E were studied in nasal lavage fluid from 60 school children with allergic seasonal rhinitis and 36 nonatopic healthy controls, before and during the pollen season. Eosinophil differential counts and IgE increased significantly in the patients during the pollen season. The eosinophil differential counts, ECP and IgE were all significantly higher during the season than in specimens simultaneously obtained from the nonatopic controls. Before season, the levels of ECP and IgE, but not eosinophils, were significantly higher in the patients than in the controls. During the season the nasal lavage fluid levels of IFN-gamma were significantly lower and the IL-4/IFN-gamma quotients significantly higher in the allergic than in the control children. In the allergic children, but not in the controls, the nasal fluid levels of the Th2 cytokines IL-4, IL-5 and IL-10 increased during the season, and together with IL-6, were correlated with the differential counts of eosinophils, and with the levels of ECP and IgE. These findings are compatible with the hypothesis that a deficient release of the Th1 cytokine IFN-gamma plays an important role in the pathogenesis of allergic inflammation. Regardless of whether the defective IFN-gamma secretion is primary or a consequence of suppression by other cytokines, it will in the atopic subjects enhance the release of Th2 cytokines, which in turn will facilitate the development of allergic inflammation.

Nonatopic wheezy children have reduced interferon-gamma

Viruses cause asthmatic exacerbations in schoolchildren. We tested the hypothesis that children who wheezed with viral respiratory tract infections secrete higher levels of the type 1 cytokine interferon-gamma (IFN-gamma) in the peripheral circulation than children who had never wheezed. Blood was taken from 13 children (eight atopic) with episodic wheeze and 11 controls. CD4 and CD8 cells were separated from peripheral blood mononuclear cells and stimulated with phorbol 12-myrisate 13-acetate (PMA) and ionomycin for 24 h. IFN-gamma, IL-4, and IL-5 were measured in the supernatant by ELISA. IFN-gamma production by CD4 and CD8 cells was lower in children with a history of wheeze (CD4, P = 0.046; CD8, P = 0.037). These children were then analysed according to atopic status. CD4 and CD8 IFN-gamma production in nonatopic wheezy children was reduced (CD4, P=0.009; CD8, P=0.003). IFN-gamma production by atopic wheezy children was lower than by controls, but the differences were not significant (CD4, P = 0.2831; CD8, P = 0.1372). CD8 IL-5 was lower in children who wheezed (P=0.012). Release of IL-4 and IL-5 by CD4 cells did not differ between the three groups. We propose that defective IFN-gamma secretion by CD4 and CD8 cells may contribute to viral-induced wheeze in nonatopic children.

Nonpathogenic common variants of IFNGR1 and IFNGR2 in association with total serum IgE levels

Atopy is an immune disorder in which a Th2 dominant mechanism leads to high IgE levels and the clinical disorder asthma. It has been postulated that the Th1 cytokine IFNgamma, acting through its heterodimeric receptors, IFNgammaR1 and IFNgammaR2, in the induction/proliferation of Th1 cells, might suppress the Th2 responses that may underlie atopic asthma. However, neither murine nor human variants of IFNgamma associate with atopy. Several dysfunctional mutations have been identified in IFNgamma receptor genes (IFNGR1 and IFNGR2) in relation to severe and selective infections with poorly pathogenic organisms. However, little is known about common polymorphisms and their functional role in atopy. To test whether such variants of IFNGR1 and IFNGR2 relate to atopic asthma, we conducted a genetic association study in both British (n = 300) and Japanese (n = 200) populations. An intronic variant of IFNGR1 showed marginal association with total serum IgE levels in the British population compared with those with total IgE levels <30 IU/ml and those with >120-500 IU/ml [odds ratio = 2.00 (95% CI 1. 00-4.07), P = 0.048]. A coding variant, Gln64Arg of the IFNGR2, also associated with total serum IgE levels in the British population [chi(2) = 5.08, P = 0.024]. Further genetic and functional analyses are needed to clarify the role of variants of IFNgamma receptor genes in atopic immune disorder among different ethnic groups.

In vitro lymphocyte reactivity to gold compounds in the diagnosis of contact hypersensitivity

The use of the lymphocyte transformation test (LTT) in the diagnosis of contact hypersensitivity to gold was studied in 8 patients who had positive patch tests to gold salts, and in 8 control subjects who were negative to such patch tests. Gold sodium thiosulfate and gold chloride were added to cultures of lymphocytes, which were labeled by 3H-thymidine after 96 h. The lymphocyte stimulation index was calculated as the beta-counts in stimulated cultures divided by those in control cultures. The index was statistically significantly higher for the patient group (p=0.005-0.04) than for the control group. Levels of interferon-gamma (IFN-gamma) were determined for the supernatants of the lymphocyte cultures. An index IFN-gamma, which is defined as the level of IFN-gamma in stimulated cultures divided by that in control cultures, was statistically significantly higher for the patient group (p=0.01-0.006). The LTT stimulation index showed specificity and sensitivity between 67 and 80%, the respective values for Index IFN-gamma being between 73 and 100% when the patch test was used as a reference method. Evaluation of lymphocyte reactivity might be of future interest in the diagnosis of allergic reactions to gold if the sensitivity and specificity can be improved.

Defective tumor necrosis factor-alpha production in infants with cow's milk allergy

As an aid to clarifying the role of immune mechanisms in the development of cow's milk allergy (CMA) in suckling infants, we studied the capacity of peripheral blood mononuclear cells (PBMC) to produce tumor necrosis factor-alpha(TNF-alpha) in vitro. The study population consisted of 43 infants, aged 0.12-11.2 months; of these, 31 had challenge-proven cow's milk allergy manifested with either skin or gastrointestinal symptoms or both. In addition, 12 healthy infants were studied as controls. The spontaneous, unstimulated and mitogen-induced production of TNF-alpha and interferon-gamma (IFN-gamma) by isolated peripheral blood leukocytes was evaluated. TNF-alpha and IFN-gamma production of PBMC was significantly lower in infants with cow's milk allergy than in healthy children. Our results indicate that, in infants with CMA, the function of TNF-alpha-producing cells is defective. This might disturb the development of oral tolerance and thereby lead to cow's milk allergy. These results may help to clarify the etiopathology of CMA.

Development of immunoglobulin G subclass antibodies to ovalbumin, birch and cat during the first eight years of life in atopic and non-atopic children

Immune responses to allergens in young children include both Th1- and Th2-like immunity, which may regulate the secretion of immunoglobulin (Ig) G subclass antibodies differently. The time, route and level of exposure to an allergen may be decisive with regard to whether sensitization or tolerance will ensue. To study this, we investigated the development of IgG subclass antibodies to food and inhalant allergens during childhood. The study group comprised a cohort of 96 children participating in a prospective study. IgG subclass antibodies to ovalbumin, Bet v 1 and cat dander were analyzed at birth, 6 and 18 months and 8 years by ELISA. IgG1 and IgG3 subclass antibodies to ovalbumin peaked at 18 months and then declined up to 8 years of age, whereas antibodies to the inhalant perennial allergen cat, but not the inhalant seasonal allergen birch, increased with age. Exposure to cat and birch tended to be associated with high antibody levels to those allergens, whereas antibody levels to ovalbumin were not related to exposure to egg. The presence of positive skin prick tests and circulating IgE antibodies correlated with high levels of IgG subclass antibody responses to the allergens. Atopic symptoms were associated with high levels of IgG subclass, particularly IgG4, antibodies to the allergens. The difference in antibody levels between atopic and non-atopic children was most marked at 6 months for ovalbumin. For the seasonal inhalant allergen birch, the difference was apparent from 18 months, whereas a difference in antibody levels to the perennial inhalant allergen cat was already present at 6 months. In conclusion, IgG subclass antibodies to food allergens peak in early infancy and are then down-regulated, whereas antibodies to the inhalant perennial allergen cat, but not the inhalant seasonal allergen birch, increase with age. Atopy is associated with high levels of IgG subclass, particularly IgG4, antibodies to allergens, supporting a deviation of the immune system towards Th2-like responses in atopic children.

Pooled human immunoglobulin inhibits IL-4 but not IFN-gamma or TNF-alpha secretion following in vitro stimulation of mononuclear cells with Staphylococcal superantigen

Intravenous immunoglobulin preparations have been successfully used in many disorders, where immunomodulation rather than immunoglobulin replacement has been the goal of therapy. The exact mechanisms by which immunoglobulin exerts its immunomodulatory effects are unclear. Proposed mechanisms include modification of T cell activation and alteration to cytokine production. As intravenous immunoglobulin therapy has been used in a number of disorders where superantigens are proposed to play a role in the disease pathogenesis, we have examined the effect of in vitro human pooled immunoglobulin on cytokine production from peripheral blood mononuclear cells in response to activation with the Staphylococcal superantigen Staphylococcal enterotoxin B. The authors found inhibition of secretion of interleukin 4 (IL-4) (P<0.001) but not interferon gamma (IFN-gamma) (P=0.13) or tumour necrosis factor alpha (TNF-alpha) (P=0.66) by pooled immunoglobulin at concentrations (6 g/l) which approximate the rise in serum immunoglobulin following in vivo IVIG therapy. Mononuclear cell proliferation was also inhibited by addition of pooled immunoglobulin to superantigen stimulated cultures. These effects do not relate to specific anti-staphylococcal enterotoxin B antibodies in the immunoglobulin preparation. The authors show that pooled human immunoglobulin can differentially modulate the secretion of IL-4 and IFN-gamma in response to superantigen stimulation.

Intracellular interferon-gamma (IFN-gamma) production in normal children and children with atopic dermatitis

A reduction in the in vitro production of IFN-gamma has been consistently described in atopic dermatitis (AD). Whether this reduction is due to a decrease in the population of peripheral blood mononuclear cells (PBMC) producing IFN-gamma or reduced IFN-gamma production per cell, or a combination of both is not clear. We have examined the intracellular production of IFN-gamma in children with AD and in healthy non-atopic controls. As Staphylococcus aureus colonization is a feature of childhood AD, and is postulated to contribute to the cutaneous inflammation in atopic dermatitis, S. aureus and Staphylococcal enterotoxin B (SEB) were used to activate PBMC. Stimulated PBMC from subjects with AD had significantly fewer IFN-gamma-containing cells in response to SEB (P < 0.001) and S. aureus (P < 0.01) than normal non-atopic children. In addition, SEB-stimulated PBMC from children with AD had less IFN-gamma per cell than normal non-atopic children (P < 0.01). Reduction in the proportion of cells containing IFN-gamma was seen in CD4+, CD8+ and natural killer (NK) cells in PBMC from children with AD. Our findings indicate that reduced production of IFN-gamma observed in childhood AD is due to both a decrease in the number of IFN-gamma-producing cells and a reduced amount of IFN-gamma production per cell. Furthermore, we found that this defect was not confined to CD4+ T cells, suggesting a more generalized defect in IFN-gamma production in childhood AD.

Blood eosinophils and serum IgE as predictors for prognosis of interferon-gamma therapy in atopic dermatitis

BACKGROUND

Interferon-gamma (IFN-gamma) therapy has been reported to be effective in atopic dermatitis. However, IFN-gamma therapy in atopic dermatitis has not yet been well established. In this study, immunologic variables were evaluated as predictors for the prognosis of IFN-gamma therapy in atopic dermatitis.

METHODS

Sixty-eight atopic dermatitis patients were each treated 18 times with 2 x 10(6) units/m2 IFN-gamma. Blood IgE level, eosinophil percentage, eosinophil count, and levels of IFN-gamma, interleukin-4 (IL-4), IL-5, and IL-10 were investigated. According to clinical responses, patients were classified into three groups: patients with improved clinical severity scores of over 20% were included in group A; those with improved scores of 20% or less in group B; and those with no improvement in group C.

RESULTS

Serum IgE levels and blood eosinophil percentages were the lowest in group A. Most atopic dermatitis patients with an eosinophil percentage over 9% and IgE level over 1500 IU/ml did not respond to IFN-gamma therapy. Initial IL-10 levels were the highest in group A. IL-4 levels in group A, and IL-5 and IL-10 levels in all groups were significantly decreased by IFN-gamma therapy.

CONCLUSIONS

IFN-gamma therapy may be recommended for atopic dermatitis patients with blood eosinophil percentages less than 9% and serum IgE levels less than 1500 IU/ml.

Sweet's syndrome: is the pathogenesis mediated by helper T cell type 1 cytokines?

BACKGROUND

The pathogenesis of Sweet's syndrome (acute febrile neutrophilic dermatosis; SS) is still not fully understood. An imbalance between helper T cell types 1 and 2 cytokine secretion patterns has been shown to be relevant in many diseases.

OBJECTIVE

We assessed the serum cytokine levels (interleukin [IL]-1alpha, IL-1beta, IL-2, interferon gamma [IFN-gamma], IL-4) in patients with SS.

METHODS

Eight patients with SS were analyzed for their clinical features and serum cytokine levels and compared with normal control subjects.

RESULTS

In patients serum levels of IL-1alpha, IL-1beta, IL-2, and IFN-gamma were significantly elevated, whereas the IL-4 level was within the normal range.

CONCLUSION

Our findings suggest that the pathogenesis of SS is probably mediated through helper T cell type 1 cytokines (IL-2, IFN-gamma) rather than helper T cell type 2 cytokines (IL-4).

Increased type 2 cytokine expression by both CD4+ CD45RO+ T cells and CD8+ CD45RO+ T cells in blood circulation is associated with high serum IgE but not with atopic dermatitis

Type 2 cytokines, such as interleukin-4 (IL-4) and IL-13, are associated with immunoglobulin E (IgE) production. This association has also been observed in CD8+ T cells from patients infected with leprosy and human immunodeficiency virus (HIV). Using intracellular cytokine staining and flow cytometry, the cytokine profile [IL-2, IL-4, IL-10, IL-13, and interferon (IFN)-gamma] of both CD4+ and CD8+ memory/effector T cells circulating in atopic dermatitis (AD) patients was investigated at the single cell level. The levels of type 2 cytokines in CD4+ T cells or CD8+ T cells in AD patients with high levels of serum IgE (AD-H), low levels of serum IgE (AD-L), and healthy controls were compared. Increased production of IL-4 and IL-13 in both CD4+ CD45RO+ T cells and CD8+ CD45RO+ T cells after 4 h in vitro stimulation with phorbol 12-myristate 13-acetate and ionomycin, was more prominent in AD-H patients than in AD-L patients or healthy controls, whereas IFN-gamma-producing CD4+ CD45RO+ T cells and CD8+ CD45RO+ T cells were relatively diminished in AD-H patients. CD4+ T cells and CD8 + T cells from AD-H patients, cultured for 48 h with phorbol 12-myristate 13-acetate and ionomycin, released larger amounts of IL-4 and IL-13 but smaller amounts of IFN-gamma than both types of cells from AD-L patients or healthy controls. In addition, when stimulated with immobilized anti-CD3 monoclonal antibody (MoAb) and anti-CD28 MoAb, CD4+ CD45RO+ T cells and CD8+ CD45RO+ T cells from AD-H patients contained more IL-4-producing cells but fewer IFN-gamma-producing cells compared with healthy controls. Finally, spontaneous mRNA expression of IL-4 in blood CD8+ CD45RO+ T cells isolated from AD-H patients was increased, as determined by reverse transcriptase-polymerase chain reaction. Therefore, in AD patients with high IgE levels, type 2 cytokine (IL-4 and IL-13) expression is associated with IgE production, in both CD4+ CD45RO+ T cell and CD8+ CD45RO+ T cell subsets.

Interleukin 4 and interferon-gamma secretion by antigen and mitogen-stimulated mononuclear cells in the hyper-IgE syndrome: no TH-2 cytokine pattern

BACKGROUND

Enhanced production of TH-2 cytokines plays a key role in increased IgE production in allergic diseases. Reports about the cytokine profile secreted by peripheral blood mononuclear cells of patients with hyper-IgE syndrome, however, are controversial, suggesting alternative causes for increased IgE production in this syndrome.

OBJECTIVE

We wished to determine whether mononuclear cells from patients with hyper-IgE syndrome have a pattern of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) production characteristic of a predominance of TH-2 cells and whether the cytokine production pattern is constant over time.

METHODS

IL-4 and IFN-gamma secretion by peripheral blood mononuclear cells stimulated with phytohemagglutinin and D. pteronyssinus was measured by ELISA in culture supernatants. Patients with the hyper-IgE syndrome were evaluated 3 times at 4-week intervals and compared with asthmatic patients and normal subjects.

RESULTS

In PHA-stimulated cultures, patients with hyper-IgE syndrome had an IL-4 and IFN-gamma secretion similar to that of controls, while asthmatic patients had increased IL-4 and decreased IFN-gamma production. Cultures stimulated with D. pteronyssinus showed a variable pattern of secretion for both cytokines.

CONCLUSIONS

In allergic diseases, increased serum IgE level is the result of a TH-2 pattern of cytokine production, with high IL-4 and decreased IFN-gamma protein secretion. The increased serum IgE concentration typical of the hyper-IgE syndrome is likely the result of a different immunoregulatory process.

Analysis of cytokine signaling in patients with extrinsic asthma and hyperimmunoglobulin E

BACKGROUND

Recent data suggest that the regulation of class switching to IgE by cytokines is mediated by STAT transcription factors. The induction of IgE by IL-4 and IL-13 occurs through the activation of the intracellular signal-transducing protein Stat6, whereas the inhibition of IgE class switching by interferon-y (IFN-gamma) occurs through the activation of Statl.

OBJECTIVE

We hypothesized that in extrinsic asthma or in cases of markedly elevated IgE (ie, hyperimmunoglobulin E [HIE]) increased levels of IgE may be associated with alterations in the cytokine levels or the activation of Stat6.

METHODS

PBMCs and sera from 8 patients with extrinsic asthma (mean IgE, 285+/-100 IU/mL), 3 patients with HIE (mean IgE, 7050+/-1122 IU/mL), and 14 nonatopic control subjects (mean IgE, 112+/-28 IU/mL) were analyzed.

RESULTS

The mean IL-4 level detected by ELISA was much greater in patients with HIE than control subjects (88.6+/-11.5 pg/mL vs 11.5+/-7.1 pg/mL, P = .005), and increased IL-4 levels among patients with both asthma and HIE correlated with the increased IgE levels. In contrast, IL-13 levels were not elevated. Levels of Stat6 protein present in PBMCs did not differ in the patients and control subjects. Examination of Stat6 DNA-binding activity demonstrated no activation of IL-4 signaling in patients with either HIE or acute asthma. Interestingly, evidence for the presence of B cells that have already switched to IgE was seen in PBMCs of several patients with asthma or HIE.

CONCLUSION

These results indicate that (1) IgE production in asthma and HIE usually is associated with elevated levels of IL-4, but not IL-13, in the peripheral blood; (2) the increased sera IL-4 levels in asthma and HIE are not sufficient to induce Stat6 activation in PBMCs; and (3) evidence of switch recombination to epsilon may be detected in isolated cases of elevated IgE. This implies that high levels of IgE in these patients either results from B cells that have already undergone class switching, from Ig class switching that is localized to target tissues, or both.

Interferon-gamma pretreatment of peripheral blood mononuclear cells partially restores defective cytokine production in children with atopic dermatitis

Interferon-gamma (IFN-gamma) is considered an important determinant of the balance between T-helper type 1 and 2 cytokines and has been used experimentally for the treatment of atopic dermatitis. However, contrasting results have been reported relative to the Th-1/Th-2 cytokine profile in atopic patients. In this study, we examined cytokine production by polyclonally activated peripheral blood mononuclear cells (PBMC) from children with atopic dermatitis, and assessed the influence of in vitro IFN-gamma pretreatment on these cells. A fraction of PBMC isolated from children with severe atopic dermatitis, as well as from age-matched controls, was initially exposed to IFN-gamma. After washing, both treated and untreated cells were then put into culture either alone or with the addition of phytohemagglutinin (PHA) or phorbol myristate acetate (PMA) plus ionomycin. IL-4, IL-5, IL-10 and IFN-gamma production were measured in the supernatants using commercially available ELISAs. PBMC from atopic patients produced more IL-4 (P = 0.04) and IL-10 (P = 0.03) and less IFN-gamma (P = 0.01) than controls, when stimulated with PHA. Interestingly, in PMA + ionomycin stimulated cultures, the atopic cytokine profile was different with more IL-5 (P = 0.0068) and less IFN-gamma production (P = 0.00046) than the control group. When cells were pretreated with IFN-gamma, there were no significant differences between patients and controls. PBMC from children with atopic dermatitis show alterations in cytokine production, compatible in general terms with the Th-1/Th-2 model. Exposure of PBMC to IFN-gamma before activation results in a reduction of these differences, so that cytokine production becomes similar in the atopic and normal groups.

Development of a human gamma interferon enzyme immunoassay and comparison with tuberculin skin testing for detection of Mycobacterium tuberculosis infection

A sensitive two-step simultaneous enzyme immunoassay (EIA) for human gamma interferon (IFN-gamma) has been developed and used as an in vitro test for human tuberculosis (TB) in comparison with tuberculin skin testing. The EIA was shown to be highly sensitive, detecting less than 0.5 IU of recombinant human IFN-gamma per ml within a linear detection range of 0.5 to 150 IU/ml. The assay was highly reproducible and specific for native IFN-gamma. In addition, the assay detected chimpanzee, orangutan, gibbon, and squirrel monkey IFN-gammas. Cross-reactions with other human cytokines or with IFN-gammas derived from mice, cattle, or Old World monkeys were not evident. The assay was used to detect TB infection by incubating whole blood overnight with human, avian, and bovine tuberculin purified protein derivatives (PPDs), as well as positive (mitogen)- and negative-control preparations. The levels of IFN-gamma in plasma supernatants were then determined. Blood from 10 tuberculin skin test-positive individuals responded predominantly to the human tuberculin PPD antigen and to a lesser extent to bovine and avian PPD antigens. By contrast, blood from 10 skin test-negative individuals showed minimal responses or no response to any of the tuberculin PPDs. Detectable levels of IFN-gamma were present in all blood samples stimulated with mitogen. In vivo tuberculin reactivity was correlated with IFN-gamma responsiveness in vitro. These results support the further study of the blood culture-IFN-gamma EIA system as an alternative to skin testing for the detection of human TB infection.

Oral food challenge increases in vitro IL-4 production by peripheral blood mononuclear cells in allergic patients

The aim of this study was to investigate interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production by peripheral blood mononuclear cells (PBMC) in response to oral challenge in patients with food allergy. Thirty-one patients were compared with 10 healthy subjects. Cell cultures were prepared before and 150 min after single-blind, placebo-controlled, oral food challenge. In vitro production of cytokines was observed after stimulation with phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). Patients were characterized according to their reactions. In vitro IL-4 production was significantly greater in patients with food sensitization than in controls. The 18 patients with positive food challenge presented significantly greater IL-4 production after food challenge than before. IFN-gamma production was not modified. In the 10 control subjects and in 13 patients with negative food challenge, IL-4 and IFN-gamma production was comparable before and after food challenge. The increased IL-4 production in patients with positive oral food challenge could account for the development of polysensitization. This situation might be relevant to other allergic diseases and to treatments.

Enhanced IL-4 but normal interferon-gamma production in children with isolated IgE mediated food hypersensitivity

Atopic disorders such as atopic dermatitis and asthma have been characterised by an imbalance in interferon-gamma (INF-gamma) and IL-4. Whether similar imbalances are found in atopic disorders with different clinical manifestations, such as IgE mediated immediate food hypersensitivity, is not clear. We have examined the in vitro production of INF-gamma and IL-4 in peripheral blood mononuclear cells (PBMC) following phytohaemagglutinin stimulation from children with isolated immediate IgE mediated food hypersensitivity (egg, milk, "nut"), children with moderate and severe atopic dermatitis, and normal children. Children with immediate food reactions were excluded if they had a history or evidence of atopic dermatitis or asthma. PBMC from children with IgE mediated food hypersensitivity produced significantly more IL-4 (p = 0.013) but equivalent INF-gamma (p = 0.26) compared to PBMC from control children. In contrast, PBMC from children with atopic dermatitis produced significantly less INF-gamma (p < 0.001) and more IL-4 (p < 0.008) than PBMC from normal children. In addition, there was no difference in IL-4 (p = 0.74) but significantly less INF-gamma (p < 0.001) produced by PBMC from the children with atopic dermatitis than food hypersensitivity. We demonstrate that children with IgE mediated food hypersensitivity and no other manifestation of atopic disease have enhanced IL-4 production without the defect in INF-gamma production observed in childhood AD and asthma. We postulate that isolated IL-4 enhancement promotes the development of IgE mediated hypersensitivity disorders such as food allergy, whilst the combination of defective INF-gamma and enhanced IL-4 production promotes inflammatory atopic disorders such as AD and asthma.

Decreased frequency of interferon-gamma-producing CD4+ cells in the peripheral blood of patients with atopic dermatitis

Recently, decreased interferon-gamma (IFN-gamma) and increased interleukin (IL)-4 production have been reported in measurements of the content of the cytokines in culture supernatants of peripheral blood mononuclear cells (PBMC) obtained from patients with atopic dermatitis (AD). These data suggest deviation of PBMC into Th2-reactive cells in AD. In the present study, we examined the frequency of IL-2-, IL-4-, and IFN-gamma-producing cells in PBMC with flow cytometry. PBMC from 16 patients with AD and 18 healthy controls were stimulated for 2 days with anti-CD3 and IL-2, and further cultured for 4 days with a maintenance dose of IL-2. Thereafter these cells were restimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin for 4 h in the presence of monensin. After fixation of the cells, the cell membranes were made permeable and intracellular cytokines were stained with anti-IL-2, anti-IL-4 or anti-IFN-gamma antibody. Cytokine-producing cells were analyzed by gating CD4+- or CD8+-subsets. Thus counted frequency of IFN-gamma-producing cells was significantly decreased in CD4+ subsets of AD patients (9.9+/-7.4%) when compared with that in the controls (20.0+/-6.7%). There was no significant difference either in the frequency of IL-2- or IL-4-producing CD4+ subsets or in that of CD8+ subsets. Furthermore, in the enzyme-linked immunosorbent assay, we also found a decreased production of IFN-gamma in the culture of PBMC from AD patients, when compared with those from healthy controls, although it was only at a marginally significant level (P=0.07). Again there was no increase in IL-4 concentration in AD patients. In addition, we found a weak negative relationship between the disease severity and the frequency of these cells. These results suggest that the decreased frequency of IFN-gamma-producing CD4+ cells with subsequently decreased production of IFN-gamma play a crucial role in the pathophysiology of AD.

Serum IgE level is negatively correlated with the ability of peripheral mononuclear cells to produce interferon gamma (IFNgamma): evidence of reduced expression of IFNgamma mRNA in atopic patients

BACKGROUND

In patients with atopic diseases such as bronchial asthma and atopic dermatitis, an elevated serum IgE level is common. Several studies showed that interleukin-4(IL-4) and interferon-gamma (IFNgamma) are important for regulation of IgE production.

OBJECTIVES

The study was designed to examine the pathogenesis of an elevated serum IgE level at the production levels of TH1-type and TH2-type cytokines.

METHODS

The production of interleukin-2 (IL-2), IL-4, interleukin-5 (IL-5) and IFNgamma by peripheral blood mononuclear cells (PBMCs) stimulated with phytohemagglutinin (PHA) was analysed in 20 individuals with various serum IgE levels. The amount of IFNgamma mRNA in the stimulated PBMCs was analysed using a quantitative polymerase chain reaction method.

RESULTS

Cytokine production was analysed simply as a function of serum IgE level. The serum IgE level was negatively correlated with the amount of IFNgamma secreted by PBMCs (n = 20, R = -0.724, P<0.005) when logarithmically transformed data were analysed, but were not or were only weakly correlated with those of IL-4, IL-2, or IL-5 secreted by these cells (n = 20). For investigation of the cause of reduced IFNgamma production in individuals whose serum IgE level are high, the amount of IFNgamma mRNA was determined. The levels of IFNgamma mRNA expression in the stimulated PBMCs correlated well with the amount of IFNgamma secreted by the PBMCs (n = 8, R = 0.947, P < 0.001).

CONCLUSIONS

Reduced IFNgamma production ability due to reduced IFNgamma mRNA expression in PBMCs is associated with an elevated serum IgE level in atopic patients.

Reduced interferon-gamma but normal IL-4 and IL-5 release by peripheral blood mononuclear cells from Xhosa children with atopic asthma

BACKGROUND

Allergic asthma is increasing in black South Africans, a cohort with inherently high basal IgE levels. Atopy has been linked to an excess of the T helper 2 cytokines IL-4 and IL-5 relative to the T helper 1 cytokine interferon-gamma (IFN-gamma); however, most studies have utilized T cell clones. Studies on peripheral blood mononuclear cells (PBMC) have shown decreased IFN-gamma release in patients with atopic dermatitis. It is uncertain whether this finding extends to atopic asthma.

OBJECTIVES

To characterize cytokine release by mitogen-activated PBMC from Xhosa children and to investigate whether reduced IFN-gamma release is a feature of atopic asthma and whether there is a relationship between cytokine profiles and asthma severity.

METHODS

Cytokine release and proliferation of phytohemagglutinin-stimulated PBMC from 10 patients with severe asthma and 14 patients with moderate asthma (highly allergic to house dust mites) and 17 healthy controls was assessed. Total serum, allergen-specific, and Ascaris-specific IgE was measured.

RESULTS

Proliferation did not differ between the groups. The release of IFN-gamma was progressively decreased (and the IL-4/IFN-gamma ratio increased) in the groups with moderate or severe asthma. Tumor necrosis factor-alpha release was reduced, but IL-4, IL-5, and granulocyte-macrophage-colony stimulating factor release was unchanged. The presence of Ascaris-specific IgE did not influence the cytokine profiles.

CONCLUSION

Our study extends the findings observed for other atopic disorders and suggests that defective IFN-gamma release is a generalized feature of atopic diseases. This study-the first to investigate both severe and moderate asthma, with the groups having similar atopic profiles-indicates that the extent of the defect in IFN-gamma release might be related to asthma severity.