Immunoglobulin production pattern is allergen-specific in polysensitized patients

The practical role of serum allergen-specific IgE as potential biomarker for predicting responder to allergen immunotherapy

Allergic asthma and rhinitis are characterized by IgE-mediated inflammation consequent to the exposure to a specific allergen. Therefore, IgE production may be considered the hallmark of allergy. Actually, allergen immunotherapy (AIT) is the unique causal treatment for respiratory allergy. Indeed, successful AIT can induce a physiologic immune tolerance toward the causal allergen. There is evidence to show that AIT is safe and effective; its indication has been rigorously stated by robust position papers. AIT efficacy assessment is mainly based on symptom reduction and drug saving. AIT responder quote may range between 60 and 90% of AIT prescription. As AIT is expensive and long-lasting, the availability of a marker able to predict AIT responder is a crucial relevance. This issue has been the topic of several studies. Very recently, it has been preliminarly reported that a cut-off of serum specific IgE levels could define AIT-responder. However, further rigorous studies will confirm this view.

The sensitising capacity of intact β-lactoglobulin is reduced by co-administration with digested β-lactoglobulin

BACKGROUND

It is generally believed that protein hydrolysis in the gastrointestinal tract decreases the allergenicity of food allergens. However, it remains unknown if specific properties of digestion products determine whether a sensitisation or tolerogenic immune response will develop. We sought to examine the sensitising capacity of the cow's milk allergen β-lactoglobulin (BLG) and digestion products thereof in a Brown Norway (BN) rat model.

METHODS

Intact BLG was digested in an in vitro model simulating the gastro-duodenal digestion process and subsequently fractionated by gel permeation chromatography. BN rats were dosed with either PBS, 200 µg of intact BLG, 30 µg of intact BLG, 200 µg of partially digested BLG, 200 µg of digested BLG, or with 200 µg of a fraction of large complexes or a fraction of small complexes. Sera from BN rats were analysed for specific antibodies and avidity was measured.

RESULTS

BLG partly resisted the digestion process. However, the BLG molecules that did not survive the digestion process were rapidly broken down to peptides of sizes less than Mr 4,500. Specific antibody responses revealed that both 200 and 30 µg of intact BLG had immunogenic as well as sensitising capacity, while digested BLG could not induce any specific antibodies. Most importantly, while intact BLG showed a significant sensitising capacity when administered alone, this sensitising capacity was significantly reduced when co-administered with digested BLG.

CONCLUSIONS

Co-immunisation of intact BLG with digested BLG reduces the sensitising capacity of intact BLG, which could result from tolerogenic mechanisms induced by the digestion products.

Relation between objective measures of atopy and myocardial infarction in the United States

BACKGROUND

Although rodent studies indicate that atherosclerosis is a T(H)1-mediated disease and that atopic T(H)2 immunity is atheroprotective, findings in humans are conflicting. Total IgE (tIgE) is associated with atherosclerotic disease but has limited specificity for atopy.

OBJECTIVE

Our aim was to determine the relation between atopy, as indicated by a broad panel of serum allergen-specific IgE (sIgE), and past myocardial infarction (MI) in a sample representative of the US population.

METHODS

Data were analyzed from 4002 participants aged ≥ 20 years from the 2005-2006 National Health and Nutrition Examination Survey.

RESULTS

Subjects reporting a history of MI had lower summed sIgE (5.51 vs 7.71 kU/L; P < .001) and were less likely to have ≥ 1 positive sIgE test (29.9% vs 44.6%; P = .02) or current hay fever (3.3% vs 7.6%; P = .002). After adjustment for age, sex, race/ethnicity, diabetes mellitus, hypertension, family history of MI, smoking, total/high-density lipoprotein cholesterol, body mass index, and C-reactive protein, the odds ratio (OR) for MI was 0.91 (95% CI, 0.85-0.97) per positive sIgE; 0.70 (95% CI, 0.57-0.85) per 2-fold increase in sum[sIgE]; and 0.82 (95% CI, 0.69-0.98) per 10% increase in the ratio of sum[sIgE] to tIgE. Analysis with 7 data-driven, prespecified allergen clusters found that house dust mite is the only allergen cluster for which sIgE is associated with reduced odds for MI (fully adjusted OR, 0.36; 95% CI, 0.20-0.64).

CONCLUSION

Serum sIgE is inversely related to MI in the US population in a manner independent of multiple coronary risk factors.

Comparison of serum specific IgE and skin prick test in polysensitized patients

The aim of this study is to evaluate serum specific-IgE in a large group of polysensitized patients with the same SPT result (such as ++++) comparing two diagnostic methods. Six hundred ten patients (310 females; median age 32 years) suffering from allergic rhinitis were studied. Serum specific-IgE were measured by ImmunoCap assay. Skin prick test was also performed. There was a significant difference between serum specific-IgE values in these polysensitized patients. In conclusion, the serum specific-IgE measurement in polysensitized patients seems to be more appropriate than SPT.

Sensitivity-related illness: the escalating pandemic of allergy, food intolerance and chemical sensitivity

The prevalence of allergic-related diseases, food intolerance, and chemical sensitivities in both the pediatric and adult population has increased dramatically over the last two decades, with escalating rates of associated morbidity. Conditions of acquired allergy, food intolerance and chemical hypersensitivity are frequently the direct sequelae of a toxicant induced loss of tolerance (TILT) in response to a significant initiating toxic exposure. Following the primary toxicant insult, the individuals become sensitive to low levels of diverse and unrelated triggers in their environment such as commonly encountered chemical, inhalant or food antigens. Among sensitized individuals, exposure to assorted inciting stimuli may precipitate diverse clinical and/or immune sequelae as may be evidenced by clinical symptoms as well as varied lymphocyte, antibody, or cytokine responses in some cases. Recently recognized as a mechanism of disease development, TILT and resultant sensitivity-related illness (SRI) may involve various organ systems and evoke wide-ranging physical or neuropsychological manifestations. With escalating rates of toxicant exposure and bioaccumulation in the population-at-large, an increasing proportion of contemporary illness is the direct result of TILT and ensuing SRI. Avoidance of triggers will preclude symptoms, and desensitization immunotherapy or immune suppression may ameliorate symptomatology in some cases. Resolution of SRI generally occurs on a gradual basis following the elimination of bioaccumulated toxicity and avoidance of further initiating adverse environmental exposures. As has usually been the case throughout medical history whenever new evidence regarding disease mechanisms emerges, resistance to the translation of knowledge abounds.

Immunoglobulin Production Pattern in Allergic and Non-Allergic Subjects

Allergic rhinitis (AR) is characterized by Th2 polarized immune response, such as increased IL-4 and reduced IFN-γ production, and by a functional defect of T regulatory cells. This impaired immune response profile influences the pattern of immunoglobulin (Ig) production in allergic patients. However, no studies have compared the pattern of inhalant allergen-specific Ig classes between allergic patients and normal subjects. The aim of this study is to therefore investigate the allergen-specific IgE, IgG, IgG4, and IgA serum level pattern in a group of patients with pollen allergy and in non-allergic healthy subjects. One hundred and two allergic patients (evaluated both out of and in the pollen season) were enrolled. In addition, 50 healthy non-allergic subjects were recruited during the whole year. Serum allergen-specific IgE, IgG, IgG4, and IgA for Parietaria, grasses, and birch were quantitatively determined by the ImmunoCAP System method. Allergen-specific IgE, IgG, IgG4, and IgA serum levels were significantly different for each tested allergen (p=0.0001 for each class) among groups. Allergic patients, mainly during pollen season, showed the highest IgG, IgG4, and IgA levels. The present study therefore provides the preliminary evidence that Ig production pattern toward inhalant allergens may depend on the specificity of the allergenic response both in non-allergic subjects and allergic patients Allergic patients do not show a defect of IgG and IgA classes. In addition, this study is the first that quantitatively evaluates the Ig classes. However, further studies should include non-allergic subjects evaluated both during and out of the pollen season.

Sublingual Immunotherapy Affects Specific Antibody and TGF-β Serum Levels in Patients with Allergic Rhinitis

Allergic rhinitis (AR) is characterized by Th2 polarized immune response, such as increased IL-4 and reduced IFN-γ production. Sublingual allergen-specific immunotherapy (SLIT) induces several immunological changes, most of which are still little known. The aim of this study is firstly to investigate the changes of allergen-specific IgE, IgG, IgG4, and IgA serum levels after SLIT. Secondly, this study aims at relating immunoglobulin (Ig) values with some Th1-, Th2-, and Treg-dependent cytokines. Twenty-three patients with pollen-induced AR were enrolled, and they assumed two pre-seasonal SLIT courses for 2 years. Serum allergen-specific IgE, IgG, IgG4 and IgA levels were determined by ELISA method at baseline and after each SLIT course. Serum IL-4, IFN-γ, IL-10, and TGF-β levels were also assessed. Allergen-specific IgE, IgG, IgG4, and IgA serum levels significantly increased after SLIT. Serum TGF-β significantly increased after SLIT. There was a significant correlation between IgA and TGF-β, both after the first and the second SLIT course. In conclusion, the present study provides the first evidence that pollen SLIT significantly affects Ig production, mainly concerning IgA; and IgA increase is related with TGF-β production. Moreover, this is the first study that measured Ig classes by using a quantitative method.