Dysregulation of IgE responses and airway allergic inflammation in atopic individuals

Serum interleukin-1beta as a marker for differentiation of asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are diseases of airway inflammation with clinical and physiological similarities, making their differentiation difficult. Airway inflammatory changes are associated with systemic changes. However, no serum marker is known for their differentiation. Therefore, serum interleukin (IL)-1beta levels were determined. Out of a total of 1023 patients screened, we included in the study ten patients each with atopic asthma, non-atopic asthma and COPD and ten healthy subjects. Skin prick tests with 14 inhalant allergens were performed on each patient. Blood was collected in the symptomatic and asymptomatic phases of the diseases and serum IL-1beta and IgE levels were determined. Our results showed that in the symptomatic phase in asthmatics, serum IL-1beta levels were higher (P<0.05) than in patients with COPD. Serum IgE levels were higher (P<0.05) in atopic asthmatics than in non-atopic asthmatics and in COPD patients. We conclude that serum IL-1beta level determination during the symptomatic phase of the diseases may help to differentiate asthmatics from patients with COPD. Serum IgE levels may differentiate atopic asthmatics from non-atopic asthmatics and COPD patients.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Interleukin-5 immunoreactivity and mRNA expression in gut mucosa from patients with food allergy

BACKGROUND AND AIMS

Eosinophils, mast cells and T lymphocytes are important cells in the allergic inflammatory process. These cells produce and are regulated by cytokines such as interleukin-3 (IL-3), interleukin-5 (IL-5) and granulocyte macrophage-colony stimulating factor (GM-CSF). We initiated this study to evaluate pathological abnormalities and to detect IL-5 in the duodenal mucosa from patients with food allergy.

METHODS

Endoscopy duodenal biopsy specimens were obtained from seven food-allergic patients, six atopic healthy controls and six nonatopic healthy controls. IL-5 protein was evaluated by immunohistochemistry. Electron microscopy as well as double immunofluorescent staining were used to identify the labelled cells and to localize IL-5. IL-5 mRNA expression was evaluated by qualitative polymerase chain reaction.

RESULTS

A significantly increased number of lymphocytes, mast cells and eosinophils was detected in the lamina propria in food-allergic patients and, in lower number, in atopic controls. Immunostaining for IL-5 was markedly positive in food-allergic patients, slightly increased in atopic controls and negative in nonatopic controls. Ultrastructurally, in food-allergic patients and in atopic controls, IL-5 was localized in eosinophil granules, in the matrix of intact granules and at the periphery of altered granules. Double immunofluorescent staining was performed in food-allergic patients and showed that 86.7% of IL-5+ cells were eosinophils, and that IL-5 was expressed by 24% of eosinophils. IL-5 mRNA was expressed in food-allergic patients but was not detected in atopic and nonatopic controls.

CONCLUSION

Activated eosinophils are involved in gut atopic reactions occurring in food allergy and are probably in part upregulated by their own local production of IL-5.

The physiology of murine germinal center reactions

Germinal center responses are the mechanism that the immune system uses normally to generate high affinity antigen-specific B-cell receptors and secreted immunoglobulins. Genetically altered mice have provided powerful tools for dissecting the physiology of these germinal center responses. In this review, we have attempted to summarize information from various sources and interpret the new observations based on what was previously known. A section is included to review the basic anatomy of the relevant structures in lymph node and spleen. A summary of the mutant mice producing a phenotype where germinal center responses are altered is also furnished. This review is aimed at providing useful information to those working in this field as well as those wishing to understand more about in vivo immunology.

Germinal center formation and local immunoglobulin E (IgE) production in the lung after an airway antigenic challenge

Airway inflammation plays a central role in the pathogenesis of asthma. However, the precise contribution of all cell types in the development and maintenance of airway hyperreactivity and histopathology during allergic inflammation remains unclear. After sensitization of mice in the periphery, challenge by multiple intratracheal (i.t.) instillations of ovalbumin (OVA) results in eosinophilia, mononuclear cell infiltration, and airway epithelial changes analogous to that seen in asthma (Blyth, D.I., M.S. Pedrick, T.J. Savage, E.M. Hessel, and D. Fattah. 1996. Am. J. Respir. Cell Mol. Biol. 14:425-438). To investigate further the nature of the cellular infiltrate, lungs from OVA-versus saline-treated mice were processed for histology and immunohistochemistry. One of the most striking features observed was the formation of germinal centers within the parenchyma of the inflamed lungs. In addition, follicular dendritic cells (FDCs) bearing OVA on their plasma membranes appeared and, adjacent to these sites, OVA-specific IgG1-, IgE-, and IgA-producing plasma cells emerged. To confirm that antigen-specific immunoglobulins (Ig) were being produced within the parenchyma, plasma cell number and antibody production were quantitated in vitro after isolation of cells from the lung. These assays confirmed that the isotypes observed in situ were a secreted product. As IgE-dependent mechanisms have been implicated as being central to the pathogenesis of bronchial asthma, airway hyperresponsiveness was evaluated. The mice undergoing lung inflammation were hyperresponsive, while the control group remained at baseline. These data demonstrate that antigen-driven differentiation of B cells via induction of an FDC network and germinal centers occurs in the parenchyma of inflamed lungs. These germinal centers would then provide a local source of IgE-secreting plasma cells that contribute to the release of factors mediating inflammatory processes in the lung.

Relationship of serum IgE concentration to level and rate of decline of pulmonary function: the Normative Aging Study

BACKGROUND

Previous reports on the relationship between serum immunoglobulin E (IgE) concentration and the level and rate of decline of pulmonary function in the general population have produced conflicting results. The relationship between total serum IgE concentration and pulmonary function was therefore examined in 1078 men aged 41-86 years followed in the Normative Aging Study.

METHODS

The serum IgE concentration determined at the start of the three year follow up period was examined in relation to both the level and longitudinal rate of decline of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC.

RESULTS

In a cross sectional analysis restricted to subjects who had ever smoked cigarettes, multiple linear regression models indicated an inverse association between total serum IgE concentration and both FEV1 (beta = -0.090 1/log10 IU/ml; SE = 0.030; p < 0.005) and FVC (beta = -0.110 1/log10 IU/ml; SE = 0.034; p < 0.005) but not FEV1/FVC, after adjustment for age and height. This relationship persisted when individuals with diagnosed asthma or methacholine hyperresponsiveness were excluded. In subjects who had never smoked cigarettes the total serum IgE concentration was unrelated to spirometric indices. No association was observed in smokers or non-smokers between the serum IgE concentration measured at the beginning of the period of follow up and the decline in FEV1, FVC, or FEV1/FVC.

CONCLUSION

Increased levels of serum IgE measured at the beginning of the follow up period are associated with lower levels of pulmonary function but are not predictive of an accelerated rate in the decline of pulmonary function among middle aged and older men.

Serum eosinophil cationic protein (ECP) in bullous pemphigoid

BACKGROUND

The importance of eosinophils in the pathogenesis of the major forms of pemphigoid (bullous pemphigoid, cicatricial pemphigoid, herpes gestationis) remains to be confirmed.

METHODS

To evaluate the role of eosinophilic infiltrates in these diseases and to detect the presence and activity of eosinophils, we compared the serum levels of eosinophil cationic protein (ECP), an eosinophil-derived protein, in 11 healthy subjects and in 10 patients with pemphigoid diseases (8 with bullous pemphigoid, one with cicatricial pemphigoid, and one with herpes gestationis). The serum of two patients with epidermolysis bullosa acquisita (EBA) and one with linear IgA bullous dermatosis (LABD) were utilized as a further control.

RESULTS

There was a significant difference between the mean of serum ECP levels in patients with pemphigoid diseases (25.1 +/- 12.3 micrograms/L, M = SD) and control subjects (2.30 +/- 2.41, micrograms/L +/- SD 2.41) (T = 4.272 P < 0.0001). The two patients with EBA (10.8 and 17.7 micrograms/L) showed contrasting results; the patient with LABD had normal ECP serum levels. The serum levels of ECP were not significantly correlated with the blood eosinophil count (R = 0.103; P = 0.777) in any of the cases.

CONCLUSIONS

In pemphigoid disease, the serum levels of ECP seem to be correlated with the activated secreting and tissue-damaging eosinophils found in the dermis, supporting the concept of an active participation of eosinophils in generating cutaneous lesions.

In vitro production of cytokines by peripheral blood mononuclear cells from hydatid patients

The role of cytokines in human hydatidosis (Echinococcus granulosus infection) was evaluated in immunoassays determining production of IL-4, IL-10 and interferon-gamma (IFN-gamma) in peripheral blood mononuclear cell (PBMC) cultures from 30 hydatid patients and 14 uninfected controls. In cell cultures from hydatid patients parasite and non-parasite antigen stimulation significantly increased IL-4 production (P < or 0.005). Spontaneous and mitogen-driven IL-4 production was similar in patients and controls. IL-10 and IFN-gamma production did not differ statistically in the two groups, even though some hydatid patients produced these cytokines in large amounts. Notably, antigen-driven IFN-gamma concentrations were invariably higher in patients than in uninfected controls. Data analysis showed a relationship between IgE and IgG4 responses and parasite-driven cytokine production. High IgE and IgG4 responders produced high IL-4 and IL-10 concentrations. High IgE responders showed decreased IFN-gamma production, but high IgG4 responders had IFN-gamma levels slightly higher than those of low responders. Cytokine response patterns did not relate to the clinical stage of disease. The significantly increased IL-4 and the high IL-10 concentrations found in PBMC from many hydatid patients in this study are consistent with Th2 cell activation in human hydatidosis. The presence of antigen-driven IFN-gamma production in patients with E. granulosus infection implies concurrent intervention of the Th1 or Th0 cell subset.

Nasal cytokines in common cold and allergic rhinitis

Coronavirus-induced common cold and allergen-induced rhinitis are characterized by nasal mucosal exudation of bulk blood plasma. The mucosal exudation process involves 'flooding' of the lamina propria with plasma-derived binding proteins and it is possible that subepithelial inflammatory cytokines and mediators may be moved by the exudate to the mucosal surface. In this study, we have analysed cytokine levels in nasal lavage (NAL) fluids from non-allergic subjects inoculated with coronavirus (n = 20) and from subjects with allergic (birch pollen) rhinitis subjected to additional allergen challenge (samples were obtained 35 min post challenge) in the laboratory (n = 10). Ten of the 20 inoculated subjects developed common cold and 10 remained healthy. Interferon-gamma (IFN gamma), interleukin-1 beta (IL-1 beta), granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-4, and IL-6 were analysed in unprocessed NAL fluids using immunoassays. The subjects who developed common cold had increased NAL fluid levels of IFN gamma (P < 0.05) that correlated well with the symptoms (P < 0.001). IFN gamma did not increase in subjects with allergic rhinitis. IL-1 beta levels were similar in NAL fluids obtained from all inoculated subjects. In the subjects with allergic rhinitis NAL fluid levels of both IL-1 beta and GM-CSF were increased (P < 0.05). GM-CSF was not detected in common cold. IL-4 and IL-6 were not detectable in any of the NAL fluids. The present cytokines may not only emanate from superficial mucosal cells. By aiding plasma exudation subepithelial cytokines may potentially also be retrieved on the mucosal surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergic models and cytokines

Cytokines are proinflammatory protein mediators produced by many cells, including mast cells, T lymphocytes, eosinophils, airway epithelial cells, and macrophages. There are numerous in vitro and in vivo animal and human studies showing that cytokines are released as a result of allergic reactions. Cytokines mediate allergic inflammation by activating eosinophils, promoting mast cell development, regulating immunoglobulin isotype switching to immunoglobulin E, modulating adhesion molecule regulation, and promoting both neutrophil and eosinophil chemotaxis. Furthermore, there are data that show the pro-inflammatory effects of cytokines may be blocked by cytokine antagonists. This report reviews the in vitro and in vivo animal and human studies of allergic models of cytokine production and regulation. It also discusses the specific roles of cytokines in the allergic inflammatory response and asthma.

Observations on the response of the nasal mucosa to allergens

Allergic rhinitis is the sixth most prevalent chronic health condition in the United States. To study the pathogenesis of the allergic response, we have used a model of nasal provocation with antigen. During the initial reaction of an allergic subject to allergen provocation, increases occur in the levels of histamine, tryptase, and prostaglandin D2. This pattern of mediator release, combined with histologic evidence of mast-cell degranulation, strongly supports the role of the mast cell in the acute allergic reaction. The response to antigen, however, does not end with mast-cell degranulation. Hours after challenge we observed the spontaneous recurrence of symptoms and increased responsiveness to antigenic and nonantigenic stimuli. Our central hypothesis is that cellular infiltration and activation after antigen challenge are responsible for the observed increase in nasal reactivity. The predominant cells in nasal lavage 24 hours after challenge are eosinophils and neutrophils, whereas the predominant cell in the mucosa is the CD4+ lymphocyte. An early step in the movement of cells from the peripheral blood involves adhesion between circulating leukocytes and the endothelium. Evidence suggests that vascular endothelial adhesion molecule may be responsible in part for the selective adherence of eosinophils to the endothelium.

Cobalt-related asthma: clinical and immunological aspects

Several clinical and experimental findings point to cobalt as the only sensitizer and causal agent of hard metal asthma. The clinical features have been clearly defined by bronchial provocation tests, with a prevalence of late phase responses. Epidemiology is still insufficient to configure prevalence and incidence rates for cobalt asthma. IgE and IgG antibodies with cobalt specificity have been demonstrated, but T-lymphocytes and eosinophils involvement seem to be important in the mechanism of an allergic inflammation in the airways. Such an immunological pathogenesis links cobalt asthma with other manifestation of hard metal disease.

Interleukin-9 potentiates the interleukin-4-induced immunoglobulin (IgG, IgM and IgE) production by normal human B lymphocytes

IgE production by normal peripheral blood lymphocytes (PBL) is known to be triggered upon stimulation by interleukin (IL)-4. In the present study we showed that IL-9, another T cell-derived cytokine, markedly potentiated IgE production induced by suboptimal doses of IL-4, whereas no effect of IL-9 was observed in the absence of IL-4. The potentiating effect of IL-9 appeared to be associated with the increased frequency of IgE-producing cells, as revealed by a specific ELISA-spot assay. Under the same experimental conditions, IL-9 also enhanced the IL-4-induced IgG production but did not elicit IgM production. However, IL-9 did not amplify the IL-4-dependent expression of membrane-bound and soluble low affinity receptor for IgE (CD23). IL-4-induced IgE production was also potentiated by IL-6 but not by tumor necrosis factor-alpha and IL-1 beta. The possibility that the activity of IL-9 was mediated by IL-6 released from accessory cells was excluded by the observations that monocyte depletion did not abolish the effect of IL-9 and that IL-9 was still active on fluorescence-assisted cell sorted CD20+ B lymphocytes co-cultured with irradiated murine EL4 cells. In addition, IL-9 was shown to potentiate the IL-4-induced IgG and IgM production by normal human B lymphocytes preactivated with Staphylococcus aureus Cowan strain. Taken together, these data suggest that IL-9 plays a regulatory role in the IL-4-dependent immunoglobulin production.

Functional interaction between beta 2-adrenoceptor agonists and interleukin-4 in the regulation of CD23 expression and release and IgE production in human

Normal human peripheral blood mononuclear cells (PBMC) produced IgE when stimulated with IL-4. In the present report it was shown that beta 2-adrenoceptor agonists, salbutamol and fenoterol, potentiated the IL-4-induced IgE production without significantly affecting the expression of the low affinity receptor for IgE at the cell surface of monocytes and B lymphocytes. However, beta 2-adrenoceptor agonists were shown to enhance at day 7 the IL-4-induced release of the soluble form of CD23 (sCD23) by PBMC. This effect was specific since a beta-adrenoceptor antagonist, D,L-propranolol, inhibited the IL-4-induced IgE production by these cells. Alternatively, the beta 2-adrenoceptor agonists inhibited the production by these cells of interferon-gamma (IFN-gamma) but did not affect the production of IL-4 when stimulated with phytohemagglutinin A + a phorbol ester. These data suggest that beta 2-adrenoceptor agonists influence the IL-4-induced IgE production in humans by enhancing the release of sCD23 and inhibiting the production of endogenous IFN-gamma. In addition to the effect on the IL-4-induced IgE production it was shown that beta 2-adrenoceptor agonists potentiated the effect of IL-4 on a human promonocytic cell line, U 937, by enhancing CD23 expression and release and by inducing the differentiation of these cells into monocyte-like cells. Taken together, these data indicate that beta 2-adrenoceptor agonists potentiated the effect of IL-4 and that this functional interaction is different considering the cell-lineage and the stage of differentiation of these cells.

Can fatal asthma be prevented?--a personal view

An increase in the mortality rate from asthma in several countries has been observed in recent years, notwithstanding the great improvement in pathophysiological findings and the introduction of new effective therapeutic agents. The phenomenon is difficult to explain but the causes of death and identification of high-risk patients have been widely studied. It is suggested that the most vital aim for physicians is the avoidance of those factors which may contribute to death from asthma. These are particularly: inadequate assessment of its severity by patients, general practitioners and hospital doctors, and inadequate and inappropriate treatment. From the diagnostic point of view, the measurement of airflow rates is necessary to establish the diagnosis in terms of reversibility, quantify the severity and assess the response to therapy. The different entity of reversibility of bronchial obstruction is due to the various mechanisms intervening in different patients. After adequate treatment, according to our observations, the reversibility is more complete in young people and when the duration of the disease is less than 2 years. Trigger factors must also be considered. From the therapeutic point of view, considering that the most important alteration in asthma is the inflammation of bronchial structures with intervention of several inflammatory cells and of numerous different chemical mediators, physicians have to apply treatment aimed at reducing inflammation rather than relying on symptomatic bronchodilator remedies. Treatment should be divided into three phases, according to symptoms: induction, consolidation and maintenance. Finally, on the basis of data here presented and of clinical experience, the essential measures for the prevention of asthma mortality are reported. If general practitioners take them into account, deaths from asthma will be reduced to a minimum.

Regulation of murine IgE responses: induction of long-lived inhibition of allergen-specific responses is genetically restricted

We previously reported that administration of high Mr glutaraldehyde-polymerized ovalbumin (OA-POL) 10 days prior to OA Al(OH)3 immunization results in 85 to 99% inhibition of primary and secondary anti-OA IgE responses and 10(2)- to 10(4)-fold increases in OA-specific IgG2a production in each of 14 inbred and 1 outbred murine strains tested. Administration of unmodified OA under the same conditions fails to inhibit IgE synthesis and yields only minor increases in IgG2a production. In the present report, the genetic restrictions placed on the capacity of this modified allergen to elicit long-lived reciprocal regulation of specific IgE and IgG2a responses were examined. Virtually permanent, antigen-specific inhibition of IgE production (greater than 90% for greater than 22 months) was elicited in C57B1/6 mice following administration of a single course of OA-POL. This inhibition was paralleled by substantial (250-fold) increases in specific IgG2a production and was dependent on the activity of extremely long-lived regulatory CD4 T cells. In contrast, BALB/c mice failed to maintain an IgE unresponsive state beyond 10-12 weeks and exhibited transient and less intense increases in IgG2a production. Examination of MHC and Igh congenic strains revealed that the induction of long-term split tolerance by these modified allergens is under multigenic control and is not solely attributable to MHC, Igh, or background genes.