Nicotine does not modulate IL-4 and interferon-gamma release from peripheral blood mononuclear cells and T cell clones activated by phorbol myristate acetate and calcium ionophore

Tobacco smoking induces an increased nonspecific IgE response. IgE synthesis is controlled by IL-4 and IFN-gamma. The effect of nicotine (10(-10) to 10(-5) M), one of the major components of tobacco smoke, were studied on IL-4 and IFN-gamma release by peripheral blood mononuclear cells from 12 allergic patients and 12 nonallergic subjects and 16 T cell clones stimulated by nonspecific agonists (phorbol myristate acetate and calcium ionophore). The release of IL-4 and IFN-gamma was measured by ELISA in supernatants after a 48-hour culture. Nicotine did not modify IL-4 and IFN-gamma release by peripheral blood mononuclear cells or T cell clones. The effects of tobacco smoke on IgE production are unlikely to change in the T cell phenotype by nicotine.     

Glucocorticoids inhibit human antigen-specific and enhance total IgE and IgG4 production due to differential effects on T and B cells in vitro

Although anti-inflammatory properties of glucocorticoids (GC) are well documented, their activity in allergic diseases is still controversial. Recently, it has been reported that GC can increase, both in vivo and in vitro, the polyclonal production of total IgE. In this study we investigated the effects of GC on the antigen (Ag)-specific IgE response in a human in vitro system with peripheral blood mononuclear cells or B cells of bee venom-sensitized individuals that allows the production of bee venom phospholipase A2 (PLA)-specific IgE and IgG4 antibodies (Ab). PLA-specific Ab were induced by simultaneously activating T cells and B cells specifically with allergen and polyclonally with anti-CD2 and soluble CD40 ligand (sCD40L) in the presence of interleukin (IL)-4. Indeed, dexamethasone and prednisolone enhanced the formation of total IgE and IgG4 in PBMC, while the production of PLA-specific IgE and IgG4 Ab was selectively inhibited in a dose-dependent manner. The suppressive effect of GC was mediated during Ag-specific stimulation and T cell-B cell interaction. This was due to GC suppressing specific T cell proliferation and cytokine production, whereas neither allergen-specific nor total IgE and IgG4 production by sCD40L/IL-4-stimulated pure B cells was affected. In contrast to GC, cyclosporine A inhibited both total and PLA-specific IgE and IgG4 secretion in peripheral blood mononuclear cells and B cell cultures. Further experiments showed that increase in nonspecific total isotype response resulted from inhibition of IL-4 uptake by cells other than B cells and sufficient availability of IL-4 to B cells for isotype switch and synthesis. Furthermore, demonstration of opposite regulatory effects of GC on specific and total isotype formation in vitro, including the inhibition of allergy-relevant Ag-specific IgE response, may contribute to a better understanding of apparently controversial observations, and explain why most allergic patients benefit from GC therapy.     

Regulation of monocyte IL-12 production: augmentation by lymphocyte contact and acute ethanol treatment, inhibition by elevated intracellular cAMP

IL-12, a monocyte-derived cytokine, is pivotal in activation of cellular immune response and inflammation. Both inflammatory response and cellular immunity are impaired by acute ethanol consumption. Here, we found that in vitro acute ethanol treatment (25-100 mM) results in a dose-dependent and significant increase of IL-12 in IFN-gamma (100 U/ml) plus Staphylococcal enterotoxin B (SEB; 1 microg/ml) stimulated monocytes and mononuclear cells but not in unstimulated cells from non-alcoholic blood donors. There was significantly greater IL-12 production in the MNC population compared to isolated Mphi (P < 0.001). Prevention of monocyte surface contact with either purified T lymphocytes or monocyte-depleted MNC resulted in a significant, 65+/-20%, decrease in IL-12 production regardless of IFN-gamma, SEB or ethanol stimulation suggesting that Mphi T-cell surface contact provides an additional signal for IL-12 production. In addition to cell surface contact, soluble mediators, particularly IL-10 and PGE2 may regulate IL-12 production. The cyclooxygenase inhibitor, Indomethacin (10(-6)M), augmented both IL-12 and IL-10 levels in isolated monocytes and mononuclear cells whether induced by medium, SEB or SEB plus 25 mM ethanol suggesting that regulation of IL-12 production via the cyclooxygenase pathway is independent of IL-10. Finally, elevation of intracellular cAMP levels by dbcAMP treatment consistently inhibited IL-12 as well as IL-10 production in monocytes induced by IFN-gamma or IFN-gamma plus 25 mM ethanol. These data suggest that augmentation of monocyte IL-12 by acute ethanol is not mediated via the cAMP pathway.     

Relationship between interferon-gamma, interleukin-4 and IgE production of lymphocytes from hen's egg-sensitive patients

We measured in vitro interferon-gamma, interleukin-4 and IgE production of peripheral blood mononuclear cells stimulated with ovalbumin. Interferon-gamma in culture supernatants of ovalbumin-stimulated peripheral blood mononuclear cells from hen's egg- sensitive patients with atopic dermatitis was significantly higher than that of healthy children or hen's egg-sensitive patients with immediate symptoms. Furthermore, in patients with atopic dermatitis who were sensitive to hen's egg and patients with immediate symptoms, there was an inverse relationship between interferon-gamma and IgE production (r = -0.535, p <0.05), and significant correlation was found between interleukin-4 and IgE production (r = 0.802, p <0.05). For the above reasons, IgE synthesis of ovalbumin-stimulated peripheral blood mononuclear cells may be suppressed by interferon-gamma in patients with atopic dermatitis. In contrast, in patients with immediate symptoms, interleukin-4 may play a major role in the pathogenesis of increased IgE production.     

IL-4 production is increased in cigarette smokers

Cigarette smoking has been associated with both increases in serum levels of total IgE and an increased risk of developing allergic-like symptoms. IL-4 and interferon-gamma (IFN-gamma) have reciprocal roles in the regulation of IgE synthesis, and as such prompted us to evaluate, in smokers, the production of these two cytokines. We demonstrate that phytohaemagglutinin (PHA)-induced IL-4 production by peripheral blood mononuclear cells (PBMC) of smokers (n = 19) is significantly higher than that of non-smokers (n = 10, P < 0.005). In addition, PBMC from heavy smokers, defined by the number of cigarettes smoked per day, produced significantly higher levels of IL-4 than those of light smokers. No difference between the groups was found for IFN-gamma production. Our data suggest an imbalance in cytokine production occurring in individuals who smoke. This imbalance, favouring IL-4 production, may be part of the mechanism responsible for the observed increases in serum IgE and allergic-like symptoms associated with cigarette smoking.     

Expression and self-assembly of Grimsby virus: antigenic distinction from Norwalk and Mexico viruses

To explore the type 1 and type 2 cytokine profile in cases coinfected with human immunodeficiency virus (HIV) and Leishmania infantum, production of interleukin-4 (IL-4), interleukin-10 (IL-10), interferon-gamma (IFN-gamma), and interleukin-2 receptor (IL-2R) was investigated in mitogen-stimulated and unstimulated peripheral blood mononuclear cell cultures from eight HIV/Leishmania coinfected subjects matched with eight anti-HIV-positive subjects with no evidence of Leishmania coinfection. Levels of IL-4 and IL-2R increased significantly from the baseline levels in the peripheral blood mononuclear cell supernatants of HIV/Leishmania coinfected subjects following stimulation with phytohemoagglutin, whereas the postchallenge concentration of IFN-gamma was significantly increased in the HIV-infected group. The levels of IL-4 and IL-10 were significantly higher in the HIV/Leishmania group throughout evaluation. Post-stimulation IFN-gamma production was significantly higher in the HIV-positive group in comparison with that of the HIV-Leishmania coinfected subjects. These observations support the notion that a Th2 cytokine response is present during a Leishmania infection, even among HIV-coinfected individuals.     

IgE secretion is attenuated by an inhibitor of proteolytic processing of CD23 (Fc epsilonRII)

CD23, the low-affinity IgE receptor, is up-regulated on interleukin (IL)-4-stimulated B cells and monocytes, with a concomitant increase in the release of soluble fragments of CD23 (sCD23) into the medium by proteolytic processing of the surface-bound intact CD23. The effect of inhibition of the processing of CD23 on IgE production in human and mouse cells and in a mouse model in vivo was evaluated. CD23 processing to sCD23 from RPMI 8866 (a human Epstein-Barr virus-transformed B cell line) cell membranes was inhibited by a broad-spectrum matrix-metalloprotease inhibitor, batimastat, with an IC50 of 0.15 microM. Batimastat also inhibited CD23 processing in whole RPMI 8866 cells as well as in IL-4-stimulated purified human monocytes with similar IC50. Batimastat inhibited IgE production from IL-4/anti-CD40-stimulated human tonsil B cells as well as mouse splenic B cells in a manner consistent with inhibition of CD23 processing. Release of soluble fragments of CD23 in the cell supernatants of tonsil B cells was inhibited over the concentration range of 1-10 microM batimastat and intact cell surface CD23 was increased on mouse splenic B cells in the presence of these concentrations of batimastat. IgE production of IL-4-stimulated human peripheral blood mononuclear cells was also blocked by 1-10 microM batimastat, again with comparable inhibition of sCD23 release over the same concentration range. Finally, in a mouse model of IgE production, batimastat inhibited IgE production in response to ovalbumin challenge as determined by serum IgE levels. Taken together, the data support a role of CD23 in IgE production and point to CD23 processing to sCD23 as a therapeutically relevant control point in the regulation of IgE synthesis.     

Effects of reconstructive surgery for left ventricular anterior aneurysm on ventriculoarterial coupling

Microbial agents are known to play a significant role in aggravating allergic diseases. Recently described viral and bacterial superantigens represent one important strategy by which infectious agents can stimulate the immune response. In previous work, we reported that the staphylococcal toxin toxic shock toxin-1 (TSST-1), a prototypic superantigen, induces in vitro total IgE synthesis after cross-linking T and B cells. This study was carried out to establish a potential link between superantigens and the enhanced IgE response to specific allergens in allergic patients. Peripheral blood mononuclear cells from atopic patients were isolated during and outside the pollen allergen season and stimulated with TSST-1, a prototypic superantigen. Total IgE and interferon-gamma production were measured in supernatants of these cultures. Outside the pollen season, TSST-1 significantly increased total IgE production only in the presence of exogenous interleukin-4, whereas during the pollen season IgE production was significantly enhanced without the need of exogenous interleukin-4. This increase in the absence of exogenous interleukin-4 was associated with significantly lower interferon-gamma production by peripheral blood mononuclear cells stimulated by TSST-1 during the pollen season. Moreover, TSST-1 stimulation of peripheral blood mononuclear cells from inhalant allergic patients was followed by an increased production of allergen-specific IgE that was restricted to the allergen to which the patient was allergic and recently exposed. In addition, TSST-1 induced on B cells the expression of B7.2, a molecule that has recently been demonstrated to enhance T helper 2 responses and to be involved in IgE regulation. This study, by demonstrating that superantigens can augment allergen-specific IgE synthesis and B7.2 expression, provides a mechanism by which microbial superantigens may modulate allergic responses.     

Analysis of cytokine and specific antibody profiles in hydatid patients with primary infection and relapse of disease

We studied in vitro cytokine production by peripheral blood mononuclear cells (PBMC) from patients with primary and recurrent hydatid disease when cells were incubated with mitogen (PHA) and antigen from hydatid cyst fluid (HCFAg); levels of specific IgE, IgG4 and eosinophil counts were also measured in sera. When specifically stimulated, PBMC from patients produced higher levels of IL-2 (P < 0.02), IFN-gamma (P < 0.0028) and IL-5 (P < 0.01) than those from uninfected donors, whereas IL-10 levels were comparable. Notably, IL-5 was also produced in higher levels (P < 0.01) by PBMC from patients when incubated with PHA. The IL-5:IFN-gamma ratio was significantly greater (P < 0.02) when measured in response to specific stimulation than it was for PHA-stimulated cultures. These cytokine data suggest a bias towards a Th2-response which is in agreement with the high levels of IgG4 and IgE observed. The polarized response appears to be related to clinical status, as differences between patients with primary infection and those with relapse of disease were demonstrated, with significantly higher levels of IgE (P < 0.003), IgG4 (P < 0.04) titres and eosinophil counts (P < 0.04) in the latter; in addition a tendency to an increased production of IL-5 buy lower IFN-gamma was also observed in this group. These results merit further study as they are suggestive of a putative role of Th2-like responses in susceptibility to reinfection by E. granulosus.     

Efficacy of traditional Chinese herbal therapy in vitro. A model system for atopic eczema: inhibition of CD23 expression on blood monocytes

Recently, there has been growing interest in the use of traditional Chinese herbal therapy (TCHT) decoctions for the treatment of atopic eczema (AE). The mode of action of this treatment is still unknown, and in order to investigate this we have analysed the effect of an extract of these herbs (TCHTE) on interleukin 4 (IL-4)-induced CD23 expression on peripheral blood monocytes from non-atopic subjects. We found that TCHTE inhibited CD23 expression up to 60% (P < 0.001), whereas the placebo extract had no significant effect on CD23 expression. This inhibition was dose-dependent, and TCHTE was effective at a concentration of 250 micrograms/ml (P = 0.001). If TCHTE or placebo was added after IL-4, the action of TCHTE could still be seen at 12 h. This inhibition was not due to cell death, as peripheral blood mononuclear cells (PBMCs) cultured with TCHTE or placebo at a concentration used in these experiments had a similar viability to control cultures. Down-regulation of the low affinity receptors for IgE on antigen-presenting cells in patients with AE may contribute to the benefit observed following treatment with TCHT.     

T cells subsets and cytokines in allergic and non-allergic children. II. Analysis and IL-5 and IL-10 mRNA expression and protein production

Interleukin 5 (IL-5) has an enhancing effect on IL-4 induced immunoglobulin E (IgE) synthesis. Furthermore, IL-5 plays an important role in the differentiation, recruitment, activation and survival of eosinophils. IL-10 has a downmodulating effect on interferon gamma (IFN-gamma) production and can exert strong anti-inflammatory activities. Therefore, we analysed whether differences were present in IL-5 and IL-10 mRNA expression and protein production between T cells of children with allergic and non-allergic asthma, atopic dermatitis and healthy control children. We demonstrated significant increases in IL-5 mRNA expression and protein production in different T cell fractions of children with allergic and non-allergic asthma and children with atopic dermatitis as compared to healthy controls. This indicates that IL-5 is not only involved in allergy, but also plays a role in the inflammatory process of non-allergic asthma. Interestingly, IL-10 mRNA expression by purified T cells of children with allergic and non-allergic asthma and children with atopic dermatitis was strongly decreased as compared with that of healthy controls. In the peripheral blood mononuclear cell (PBMC) fraction, IL-10 mRNA expression was comparable between the four groups. We hypothesize that this decreased T cell derived IL-10 expression results in a lack of immunosuppression of the inflammatory process in these diseases. However, a role of monocyte derived IL-10 cannot be ruled out.     

Allergen-induced cytokine production in atopic disease and its relationship to disease severity

The Th2 cytokines, interleukin (IL)-4 and IL-5, have an important role in atopic disease. CD30 is a transmembrane molecule that may be expressed on a proportion of activated T-lymphocytes and has been reported to be a marker for Th2 phenotype. Our objective was to compare the in vitro cytokine responses and CD30 expression of peripheral blood mononuclear cells (PBMCs) to stimulation with house dust mite antigen (Dermatophagoides pteronyssinus) in atopic asthmatics, atopic nonasthmatics, and normal subjects, and to see if atopic asthmatic cytokine production correlated with symptomatic disease activity and whether cytokine production was allergen-specific. Eighteen atopic asthmatics (all were allocated a symptomatic disease score), 6 atopic nonasthmatics, and 7 healthy nonatopic individuals were studied. Resting serum IL-4 levels were measured, then PBMCs were separated using Lymphoprep density centrifugation and cultured in modified RPMI 1640 medium. PBMCs were stimulated with IL-2 alone or with D. pteronyssinus (1,000 subcutaneous units/ml) with IL-2 and harvested after 5 and 10 d. Using monoclonal antibodies and flow cytometry we obtained the percentage of CD4+ T cells expressing CD30 and the intensity of CD30 staining. Culture supernatants were analyzed for IL-4 and interferon gamma (IFN-gamma) using an enzyme-linked immunosorbent assay. In 9 atopic asthmatics PBMCs were also stimulated nonspecifically using phytohemagglutinin (PHA). IL-4 was detectable in the serum of atopic subjects but not in normal subjects. Stimulation of PBMCs with D. pteronyssinus produced significant amounts of IL-4 in atopic asthmatics and atopic nonasthmatics, but minimal quantities in normal subjects. Much lower levels of IFN-gamma were produced by atopic asthmatics in response to D. pteronyssinus compared to atopic nonasthmatics. IFN-gamma levels had an inverse correlation with asthmatic symptom score. CD4+ T-cell expression of CD30 also correlated inversely with IFN-gamma production and IFN-gamma:IL-4 ratio. PHA produced minimal levels of IL-4 compared to specific allergen stimulation. It is concluded that different groups of atopic patients exhibit different patterns of allergen-induced cytokine production. In vitro allergen-induced cytokine production in atopic asthmatics correlated with symptomatic disease activity, and is allergen-specific.     

IL-15 enhances the response of human gamma delta T cells to nonpeptide [correction of nonpetide] microbial antigens

Human gamma delta T cells have the ability to rapidly expand and produce IFN-gamma in response to nonpeptide Ags of microbial pathogens, in particular a class of compounds known as the prenyl phosphates. We investigated the ability of IL-15, a T cell growth factor, to modulate prenyl phosphate-induced gamma delta T cell proliferation and cytokine production. IL-15 significantly enhanced the expansion of gamma delta T cells in the peripheral blood after stimulation in vitro with isopentenyl pyrophosphate. Moreover, using gamma delta T cell clones, we determined that IL-15-induced T cell proliferation was dependent on the IL-2R beta chain but not the IL-2R alpha chain. We therefore studied the IL-15R alpha chain expression in human gamma delta T cells in the presence or absence of nonpeptide Ags. We found IL-15R alpha mRNA expression in IL-15-stimulated and Ag-stimulated human gamma delta T cells but not in resting gamma delta T cells. Although IL-15 itself had little effect on the production of IFN-gamma, IL-15 plus IL-12 acted synergistically to augment IFN-gamma production by gamma delta T cells. Moreover, we showed that this increase in IFN-gamma could be explained by the dual activation of STAT1 and STAT4 by IL-15 and IL-12, respectively. Taken together, these results suggest that IL-15 may contribute to activation of human gamma delta T cells in the immune response to microbial pathogens.     

Differential regulation of human T cell cytokine patterns and IgE and IgG4 responses by conformational antigen variants

Bee venom phospholipase A2 (PLA) represents the major allergen and antigen in allergic and non-allergic individuals sensitized to bee sting. We have studied specific activation of peripheral T cells by different structural and conformational variants of PLA and secretion of cytokines regulating IgE and IgG4 antibody (Ab) formation. PLA molecules expressing the correctly folded tertiary structure, which show high affinity to membrane phospholipids and were recognized by Ab from bee sting allergic patients, induced high IL-4, IL-5 and IL-13 production in peripheral blood mononuclear cell cultures. In contrast, non-refolded recombinant PLA (rPLA) and reduced and alkylated native PLA (nPLA) induced more IFN-gamma and IL-2 and higher proliferative responses. Differences in proliferation and cytokine patterns among correctly folded and non-refolded PLA resulted from conformation-dependent involvement of different antigen-presenting cell (APC) types. Antigen (Ag)-presenting B cells recognized PLA only in its natural conformation, stimulated Th2 type cytokines and induced IgE Ab. Non-refolded PLA was recognized, processed and presented exclusively by monocytes and induced a Th1 dominant cytokine profile leading to IgG4 production by B cells. The possibility that production of particular cytokine patterns and Ig isotype was influenced by the enzymatic activity of PLA was excluded by using enzymatically inactive H34Q point-mutated, refolded rPLA. These findings demonstrate the decisive role of specific Ag recognition by different APC, depending on structural features, membrane phospholipid binding property and the existence of conformational B cell epitopes, in the differential regulation of memory IgE and IgG4 Ab. Furthermore, they show that a change from IgE-mediated allergy to normal immunity against a major allergen can be induced by rPLA variants that are not recognized by specific Ab and B cells but still carry the T cell epitopes. These features may enable new applications for safer immunotherapy.     

Effects of IL-4 and IL-13 on total and allergen specific IgE production by cultured PBMC from allergic patients determined with recombinant pollen allergens

BACKGROUND: Interleukin (IL)-4 and IL-13 have been shown to be potent switch factors for IgE synthesis in human B cells. OBJECTIVE: In this study we investigated the effects of recombinant human IL-4 and IL-13 on total and allergen specific IgE synthesis by peripheral blood mononuclear cells (PBMC) from pollen allergic patients and healthy control individuals. METHODS: Peripheral blood mononuclear cells (PBMC) from allergic patients were investigated for their capacity to produce allergen specific IgE in vitro. Total protein extracts from birch pollen and timothy grass pollen as well as purified recombinant birch pollen allergens, Bet v I, birch profilin (Bet v II) and recombinant timothy grass pollen allergens, Phl p I, Phl p II, and Phl p V were used to measure specific IgE-antibody synthesis in cell culture supernatants by IgE-immunoblot and ELISA. RESULTS: PBMC obtained from allergic patients spontaneously secreted allergen specific IgE in the culture supernatants. Addition of Interleukin 4, Interleukin 13 and anti-CD40 antibody to the cultures alone or in combinations significantly induced total IgE production whereas allergen specific IgE production was not affected. CONCLUSION: Our results indicate that the peripheral blood of allergic individuals contains long lived allergen specific B cells which have already switched to IgE production and which are not sensitive to IL-4 and IL-13 treatment. These results may have implications on attempts to use cytokines or cytokine antagonists in therapy of Type I allergy.     

Antigen-stimulated IL-4, IL-13 and IFN-gamma production by human T cells at a single-cell level

To understand the intricate balance and the coordinate expression of the Th1 and Th2 cytokines following a natural mode of T cell triggering, antigen-stimulated IL-4, IL-13 and IFN-gamma production was studied in primary peripheral blood mononuclear cell cultures at a single-cell level. Cells from filariasis patients who respond to parasite antigen by producing not only IFN-gamma but also IL-4 and IL-13 were stimulated with Brugia malayi adult worm antigen and analyzed for co-expression of cytokines by intracellular staining. IL-4 and IL-13 were frequently co-expressed (54% of IL-4+ cells stained for IL-13 and 29% of IL-13+ cells expressed IL-4 at all time points), whereas IFN-gamma expression was totally segregated from both IL-4 and IL-13. These data indicate that in human peripheral T cells the co-expression of the dominant Th1 and Th2 cytokines within a single cell is a rare event and that IL-13 is clearly more frequently associated with a Th2 than a Th1 type response in primary T cell cultures.     

Role of transforming growth factor-beta in the preferential induction of T helper cells of type 1 by staphylococcal enterotoxin B

Stimulation of murine CD4+ T cells with staphylococcal enterotoxin B (SEB) results in the preferential development of T helper (Th) 1 cells [i.e. high interferon (IFN)-gamma and low interleukin (IL)-4, IL-5 and IL-10]; whereas in response to plate-bound anti-CD3 or anti-T cell receptor-alpha beta, Th1 as well as Th2 cells develop. In the present study, we examined the mechanism which is responsible for the selective Th1 development in the SEB system. The addition of IL-4 resulted in a strong development of Th2 cells showing that SEB stimulation can result in Th2 differentiation. Co-stimulation with anti-CD28 was insufficient in this regard. Lack of Th2 development in the SEB system was in part due to the inhibitory effect of endogenously produced transforming growth factor-beta (TGF-beta), because anti-TGF-beta allowed the development of Th2 cells. Similarly, TGF-beta inhibited Th2 development and stimulated Th1 development in the anti-CD3 system. This shift was only partially prevented by also including IL-4 in the cultures. The effects of TGF-beta could only partially be explained by stimulation of IFN-gamma or inhibition of IL-4 as intermediatory cytokines: (1) TGF-beta stimulated Th1 development even in the presence of anti-IL-4 and anti-IFN-gamma, and (2) a strong inhibitory effect of anti-TGF-beta on Th1 development was still observed when anti-IL-4 and IFN-gamma were simultaneously added to the cultures. It is concluded that SEB favors Th1 development by stimulation of TGF-beta production. Inhibition of Th2 development by TGF-beta is due, in part, to inhibition of IL-4 and stimulation of IFN-gamma, and, in part, to a direct effect of TGF-beta on the responding T cells.     

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.     

Co-stimulation of cultured peripheral blood mononuclear cells from intrinsic asthmatics with exogenous recombinant IL-6 produce high levels of IL-4-dependent IgE

Asthma is an inflammatory airway disorder, traditionally subdivided into extrinsic, immunoglobulin E (IgE)-mediated, and intrinsic asthma of unknown aetiology. IgE synthesis requires contact between T- and B-cells and a signal provided by interleukin (IL)-4, which can be modulated by IL-6. The objective of this study was to evaluate the effects of IL-4 and IL-6 on total IgE synthesis by peripheral blood mononuclear cells from intrinsic and extrinsic asthmatics. Peripheral blood mononuclear cells from intrinsic and extrinsic asthmatic patients and from healthy subjects were cultured and stimulated with pokeweed mitogen, recombinant IL-4 and IL-6. The IgE level in serum and supernatants was measured by an enzyme-linked immunoassay. Serum IgE was significantly lower in intrinsic asthma than in extrinsic asthma, but significantly higher than in control subjects. IgE production by cultured mononuclear cells from extrinsic asthmatics was not modified after exogenous IL-4 and IL-6 addition. However, intrinsic asthmatics showed enhancement of IgE synthesis in response to IL-4 stimulation, reaching a threefold increase of the spontaneous IgE values, when simultaneous recombinant IL-4 plus IL-6 stimulus was used. Our results indicate that exogenous recombinant interleukin-6 can significantly upregulate the interleukin-4-dependent immunoglobulin E synthesis in intrinsic asthma. This suggests that immunoglobulin E could also play a role in the pathogenesis of intrinsic asthma, in which an interleukin-6 threshold would be critical.