Duration of clinical reactivity in cow's milk allergy is associated with levels of specific immunoglobulin G4 and immunoglobulin A antibodies to β‐lactoglobulin

Background The development of tolerance in IgE‐mediated allergies has been associated with lower cow's milk (CM)‐specific IgE levels, increasing levels of specific IgG4 and, more contestably, IgA. Objective We investigated whether specific antibody responses to CM proteins differ over time between patients who recovered from cow's milk allergy (CMA) by the age of 3 years and those who developed tolerance only after the age of 8 years. Methods The study population comprised of 83 patients with IgE‐mediated CMA. They belonged to a cohort of 6209 healthy, full‐term infants followed prospectively for the emergence of CMA. Serum samples were available at diagnosis (median age 7 months), 1 year later (median 19 months) and at follow‐up (median 8.5 years). Age‐matched control subjects with no history of CMA (n=76) participated in the follow‐up. Serum levels of IgE antibodies to CM were measured using UniCAP. Levels of IgA, IgG1 and IgG4 antibodies to β‐lactoglobulin and α‐casein were measured using ELISA. Results Patients with persistent CMA at the age of 8 years (n=18 at diagnosis, n=16 at later time‐points) had higher CM‐specific IgE levels at all three time‐points (P<0.001) compared with patients who became tolerant by 3 years (n=55 at diagnosis, n=54 a year later, n=40 at follow‐up). They had lower serum IgA levels to β‐lactoglobulin at diagnosis (P=0.01), and lower IgG4 levels to β‐lactoglobulin (P=0.04) and α‐casein (P=0.05) at follow‐up. Conclusion High CM‐specific IgE levels predict the persistence of CMA. Development of tolerance is associated with elevated levels of β‐lactoglobulin‐specific serum IgA at the time of diagnosis, and later increasing specific IgG4 levels to β‐lactoglobulin and α‐casein. Cite this as: E. M. Savilahti, K. M. Saarinen and E. Savilahti, Clinical & Experimental Allergy, 2010 (40) 251–256.     

Probiotics in infancy induce protective immune profiles that are characteristic for chronic low-grade inflammation

Background Probiotics are widely studied both in the treatment and prevention of allergic diseases, but their mode of action is poorly known. Objective Our aim was to examine the effect of probiotic bacteria on in vivo cytokine, antibody, and inflammatory responses in allergy‐prone infants. Methods In a randomized double‐blind study, probiotic bacteria or placebo were given for 1 month before delivery to mothers and for 6 months to infants with a family history of allergy. Plasma samples were analysed for C‐reactive protein (CRP), total IgA and IgE, food‐specific IgA, IgG, and IgE, IL‐2, IL‐4, IL‐6, IL‐10, TNF‐α, and IFN‐γ. We analysed the associations of immunological and inflammatory parameters at age 6 months with probiotic treatment and allergic phenotype at 2 years. Results Infants receiving probiotic bacteria had higher plasma levels of CRP (P=0.008), total IgA (P=0.016), total IgE (P=0.047), and IL‐10 (P=0.002) than infants in the placebo group. Increased plasma CRP level at age 6 months was associated with a decreased risk of eczema [odds ratio (OR) 0.41 [95% confidence interval (CI) 0.17–0.99], P=0.046], and with a decreased risk of allergic disease [OR 0.38 (95% CI 0.16–0.87), P=0.023] at age 2 years, when adjusted with probiotic use. Conclusion The association of CRP with a decreased risk of eczema at 2 years of age in allergy‐prone children supports the view that chronic, low‐grade inflammation protects from eczema. Probiotic‐induced low‐grade inflammation was characterized by elevation of IgE, IgA, and IL‐10, the changes typically observed in helminth infection‐associated induction of regulatory mechanisms. The findings emphasize the role of chronic microbial exposure as an immune modulator protecting from allergy.     

Clinical usefulness of microarray-based IgE detection in children with suspected food allergy

Background: Component‐resolved diagnostics using microarray technology has recently been introduced into clinical allergology, but its applicability in children with food allergy has hardly been investigated so far. The aim of this study was to evaluate the utility of microarray‐based IgE detection in the diagnostic workup of food allergy and to compare this new diagnostic tool with established methods of allergen‐specific IgE detection. Methods: We investigated 130 infants and children with suspected allergy to cow’s milk (CM) or hen’s egg (HE). Serum IgE measurements, skin prick tests, allergen microarray assays and controlled oral food challenges with HE and CM were performed. Results: We analyzed 145 oral challenges that served as reference parameters for assay performance assessment. On this basis, the panel of microarrayed allergen components was shown to represent a comprehensive repertoire of clinically relevant CM and HE proteins. Additionally, the implemented CM and HE components respectively sufficed for equivalent test performance as compared to the corresponding fluorescence enzyme immunoassay extract and skin testing. However, component‐resolved diagnostics for HE and CM allergy did not make oral food challenges superfluous. Clinical IgE decision points predicting positive oral food challenges could be calculated for both in vitro test methods. Conclusions: Allergen microarrays provide a new tool to diagnose symptomatic CM and HE allergy. They show performance characteristics comparable to the current diagnostic tests and may be indicated in small children in whom only small blood volumes are obtainable. However, they are not capable of replacing double‐blind, placebo‐controlled food challenges in most cases.     

Patterns of immunoglobulin G responses to egg and peanut allergens are distinct: ovalbumin-specific immunoglobulin responses are ubiquitous, but peanut-specific immunoglobulin responses are up-regulated in peanut allergy

BACKGROUND: The clinical significance of food-specific IgG subclasses in food allergy and tolerance remains unclear. Specific IgG titres are often reported in non-standardized units, which do not allow comparisons between studies or allergens. OBJECTIVE: To quantify, in absolute units, ovalbumin (OVA)- and peanut-specific IgG levels in children with peanut or egg allergy (active or resolved) and in non-allergic controls. Methods Children aged 1-15 years were recruited. Peanut allergy was diagnosed by convincing history and a 95% predictive level of specific IgE; egg allergy or resolution was confirmed by oral challenge. Serum IgG, IgG1 and IgG4 levels (microg/mL) to OVA and peanut extract were quantified by ELISA. RESULTS: OVA- and peanut-specific IgG was detected in all subjects. In non-allergic controls (n=18), OVA-specific IgG levels were significantly higher than peanut-specific IgG (median microg/mL IgG=15.9 vs. 2.2, IgG1=1.3 vs. 0.6, IgG4=7.9 vs. 0.7; P<0.01). There were no differences in OVA-specific IgG, IgG1 and IgG4 between egg-allergic (n=40), egg-resolved (n=22) and control (n=18) subjects. In contrast, peanut-specific IgG (median microg/mL IgG=17.0, IgG1=3.3, IgG4=5.2) were significantly higher in peanut-allergic subjects (n=59) compared with controls and with non-peanut-sensitized but egg-allergic subjects (n=26). Overall, the range of IgG4 was greater than IgG1, and IgG4 was the dominant subclass in >60% of all subjects. CONCLUSION: OVA-specific IgG levels of egg-allergic, egg-resolved or control groups are not distinguishable. Higher peanut-specific IgG levels are associated with clinical allergy, but the range of IgG titres of the allergic and control groups overlapped. Hence, OVA and peanut-specific IgG measurements do not appear to be of diagnostic value. Strong IgG responses to OVA may be a normal physiological response to a protein frequently ingested from infancy, whereas up-regulated IgG responses in peanut allergy may be indicative of a dysregulated immune response to peanut allergens.     

The critical role of allergen-specific IgE,IgG4 and IgA antibodies in the tolerance of IgE-mediated food sensitisation in primary school children

Primary objective. There are about 6% of children who are either intolerant to or lose their ability to tolerate food allergens, resulting in the development of food hypersensitivity. The hypothesis that increase in food allergen-specific IgE antibody level is associated with the decrease in the levels of food allergen-specific IgG4 and IgA antibodies was used as a biomarker of food tolerance. Methods & Procedures. The Modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire (added gastrointestinal allergy questions) and Phadiatop infant test were used to screen one hundred 6–8-year-old allergic school children. Food allergen-specific IgE, IgG and IgA antibodies were measured by using the Phadia ImmunoCAP system radioabsorbent test (RAST). Immunoglobin E antibodies to common aeroallergens, were also detected by enzyme-linked immunosorbent assay. Main outcome. The level of analysed food specific-IgE antibody was obviously higher in the study population. Sensitivity to dust mites among the children was nearly 90%, and that to cockroach was 47%. Egg white-, cow's milk-, α-lactoalbumin-, β-lactoglobulin- and casein-specific IgG4/IgE and IgA/IgE ratios were lower in the atopic school children but not in the tropomysin-, mango- and kiwi-sensitive participants. Conclusion. The level of cow's milk- and egg white-specific IgE antibody still remained high along with a decrease in the specific IgG4/IgE and IgA/IgE ratios in our study population. Therefore, allergen-specific IgG4 and IgA antibodies are important biomarkers of tolerance establishment, and failure to establish tolerance to food allergens may be related to the regulation of the inhalant allergens encountered in late childhood stages.     

Sublingual grass pollen immunotherapy is associated with increases in sublingual Foxp3‐expressing cells and elevated allergen‐specific immunoglobulin G4, immunoglobulin A and serum inhibitory activity for immunoglobulin E‐facilitated allergen binding to B cells

Background The mechanisms of sublingual immunotherapy (SLIT) are less well understood than those of subcutaneous immunotherapy (SCIT). Objectives To determine the effects of grass‐pollen SLIT on oral mucosal immune cells, local regulatory cytokines, serum allergen‐specific antibody subclasses and B cell IgE‐facilitated allergen binding (IgE‐FAB). Methods Biopsies from the sublingual mucosa of up to 14 SLIT‐treated atopics, nine placebo‐treated atopics and eight normal controls were examined for myeloid dendritic cells (mDCs) (CD1c), plasmacytoid dendritic cells (CD303), mast cells (AA1), T cells (CD3) and Foxp3 using immunofluorescence microscopy. IL‐10 and TGF‐β mRNA expression were identified by in situ hybridization. Allergen‐specific IgG and IgA subclasses and serum inhibitory activity for binding of allergen‐IgE complexes to B cells (IgE‐FAB) were measured before, during and on the completion of SLIT. Results Foxp3⁺ cells were increased in the oral epithelium of SLIT‐ vs. placebo‐treated atopics (P=0.04). Greater numbers of subepithelial mDCs were present in placebo‐treated, but not in SLIT‐treated, atopics compared with normal controls (P=0.05). There were fewer subepithelial mast cells and greater epithelial T cells in SLIT‐ compared with placebo‐treated atopics (P=0.1 for both). IgG₁ and IgG₄ were increased following SLIT (P<0.001). Peak seasonal IgA₁ and IgA₂ were increased during SLIT (P<0.05). There was a time‐dependent increase in serum inhibitory activity for IgE‐FAB in SLIT‐treated atopics. Conclusions SLIT with grass pollen extract is associated with increased Foxp3⁺ cells in the sublingual epithelium and systemic humoral changes as observed previously for SCIT. Cite this as: G. W. Scadding, M. H. Shamji, M. R. Jacobson, D. I. Lee, D. Wilson, M. T. Lima, L. Pitkin, C. Pilette, K. Nouri‐Aria and S. R. Durham, Clinical & Experimental Allergy, 2010 (40) 598–606.     

Serum ovalbumin-specific immunoglobulin G responses during pregnancy reflect maternal intake of dietary egg and relate to the development of allergy in early infancy

BACKGROUND: The value of allergen elimination diets during pregnancy for primary prevention of infant allergy has been questioned. However, dietary compliance may influence effectiveness. OBJECTIVES: To monitor egg intake during a randomized controlled trial of egg avoidance throughout pregnancy and lactation by serial measurements of serum ovalbumin (OVA) IgG concentration in conjunction with dietary diary record and also, to analyse specific IgG concentrations at birth in relation to infant allergic outcome. METHODS: Pregnant women, with personal or partner atopy, were randomized to complete dietary egg exclusion or an unmodified healthy diet before 20 weeks gestation. The infants were evaluated for atopy at 6 months of age. Serum food-specific IgG concentrations were determined by ELISA in maternal samples collected at study recruitment and during labour, and in infant samples at birth (umbilical cord). RESULTS: Serum-specific IgG to OVA, but not the unrelated allergen, cow's milk beta-lactoglobulin, decreased over pregnancy in egg-avoiding women only (P<0.001). Cord OVA IgG concentration correlated with maternal IgG at delivery (r=0.944; P<0.001), and for infants born to atopic women, cord concentration was higher than that of their mother's (P<0.001). Infants with the lowest and highest cord IgG concentrations were the least likely, and those with mid-range concentrations were the most likely, to be atopic by 6 months of age (P=0.008). CONCLUSION: Serum OVA IgG concentration reflects egg consumption, thereby indicating dietary allergen doses to which the developing immune system might be exposed. Trans-placental maternal IgG must be considered among early life factors that regulate infant atopic programming.     

Allergen-specific antibody and cytokine responses, mast cell reactivity and intestinal permeability upon oral challenge of sensitized and tolerized mice

Background Food allergy has reached an epidemic level in westernized countries and although central mechanisms have been described, the variability associated with genetic diversity underscores the still unresolved complexity of these disorders. Objective To develop models of food allergy and oral tolerance, both strictly induced by the intestinal route, and to compare antigen‐specific responses. Methods BALB/c mice were mucosally sensitized to ovalbumin (OVA) in the presence of the mucosal adjuvant cholera toxin, or tolerized by intra‐gastric administrations of OVA alone. Antibody titres and cytokines were determined by ELISA, and allergic status was determined through several physiologic parameters including decline in temperature, diarrhoea, mast cell degranulation and intestinal permeability. Results OVA‐specific antibodies (IgE, IgGs and IgA in serum and feces) were produced in sensitized mice exclusively. Upon intra‐gastric challenge with OVA, sensitized mice developed anaphylactic reactions associated with a decline of temperature, diarrhoea, degranulation of mast cells, which were only moderately recruited in the small intestine, and increased intestinal permeability. Cytokines produced by immune cells from sensitized mice included T‐helper type 2 cytokines (IL‐5, IL‐13), but also IL‐10, IFN‐γ and IL‐17. In contrast, all markers of allergy were totally absent in tolerized animals, and yet the latter were protected from subsequent sensitization, demonstrating that oral tolerance took place efficiently. Conclusion This work allows for the first time an appropriate comparison between sensitized and tolerized BALB/c mice towards OVA. It highlights important differences from other models of allergy, and thus questions some of the generally accepted notions of allergic reactions, such as the protective role of IFN‐γ, the importance of antigen‐specific secretory IgA and the role of mucosal mast cells in intestinal anaphylaxis. In addition, it suggests that IL‐17 might be an effector cytokine in food allergy. Finally, it demonstrates that intestinal permeability towards the allergen is increased during challenge. Cite this as: C. Perrier, A.‐C. Thierry, A. Mercenier and B. Corthésy, Clinical & Experimental Allergy, 2010 (40) 153–162.     

Adoptive transfer of dendritic cells from allergic mice induces specific immunoglobulin E antibody in naïve recipients in absence of antigen challenge without altering the T helper 1/T helper 2 balance

Dendritic cells (DCs) are important in the regulation of immune responses and it has been proposed that these cells play an important role in asthma; however, their role in food allergy is still largely unknown. Our aim was to study specific immunoglobulin E (IgE) and immunoglobulin G (IgG) responses in naïve recipients following adoptive transfer of myeloid DCs from allergic and control mice. The phenotypic features and lymphokine production of DCs were also investigated. CD11c ^{+ /hi} B220^? DCs isolated from spleen and Peyer's patches (PP) of cow's milk (CM) allergic and control mice were transferred intravenously (i.v.) into naïve syngeneic recipients, and IgE‐ and IgG‐specific responses were evaluated. Experiments were also carried out to determine the levels of interferon‐γ (IFN‐γ) and interleukin (IL)‐4 produced by splenocytes from naïve recipients following the adoptive transfer, and CD40 ligand (CD40L)‐mediated IL‐10 production by DCs from allergic and control mice. DCs isolated from spleen and PP of allergic mice, but not control groups, induced CM‐specific IgG and IgE antibody production in naïve recipients in the absence of previous immunization, but did not modify the T helper 1 (Th1) and T helper 2 (Th2) balance. Furthermore, although no difference was observed in the expression of canonical DC surface markers, PP DCs from allergic mice produced less IL‐10 than DCs from controls. We interpret these data as showing that DCs play a pivotal role in allergen‐specific IgE responses and that a Th2‐skewed response may not be involved in the early phase of allergic responses. The identification of the mechanisms underlying these events may help to design novel strategies of therapeutic intervention in food allergy.     

Maintenance of tolerance to cow''s milk in atopic individuals is characterized by high levels of specific immunoglobulin G4

BACKGROUND: The central role of specific IgE in cow's milk allergy (CMA) is well documented. However, less is known about the function of other immunoglobulin isotypes in allergy and tolerance to cow's milk proteins (CMPs). OBJECTIVE: To determine differences in the antibody responses that are associated with allergy and tolerance to cow's milk in allergic, atopic and non-atopic individuals of different age groups. METHODS: Nineteen infants (<1 year), 18 children (6-14 years) and 41 adults (21-68 years) were included. Each age group was comprised of subjects with CMA, atopic individuals without a history of CMA and non-atopic subjects. Levels of specific IgE, IgG4, IgG1 and IgA to whole cow's milk and the six most abundant individual CMPs were determined in plasma by ELISA. For comparison, specific IgE and IgG4 were measured to ovomucoid and house dust mite (HDM) in individuals allergic for the respective allergens, and in atopic and non-atopic subjects without allergy. RESULTS: In infants and children with CMA, alphas1-casein and beta-lactoglobulin induced the highest specific IgE response, whereas alphas1-casein was the most allergenic CMP in adult patients. Specific IgG4 and IgG1 responses were the highest to alphas1-casein and beta-lactoglobulin in all age groups, while kappa-casein and alpha-lactalbumin induced the highest levels of IgA. CMP-specific IgG4 was higher in atopic children and adults without CMA, as compared with non-atopic individuals. A similar difference between tolerant atopic and non-atopic subjects was observed for IgG4 specific to ovomucoid, whereas HDM-specific IgG4 was not detectable in these subjects. CONCLUSION: Maintenance of tolerance to cow's milk in atopic children and adults without CMA is associated with elevated levels of specific IgG4, in combination with low specific IgE. The up-regulation of specific IgG4 in tolerant atopic individuals may be related to the type of allergen and its regular dose of exposure.     

Specific IgA and IgE in childhood asthma, eczema and food allergy

Allergen-specific IgA and IgE antibodies were compared in 250 children with asthma (Dermatophagoides pteronyssinus, rye grass pollen), in eighty-six children with eczema (whole egg, cow's milk) and in two groups of children with egg and cow's milk allergy. In each of the conditions investigated, food allergy, asthma and eczema, increasing atopy was associated with increasing specific IgE levels to relevant allergens. There was no association of high IgE antibody levels with low IgA antibody levels in any of the conditions or allergens studied. There was, however, a tendency for subjects with more severe asthma to have high IgA levels with high IgE levels. IgA deficiency does not appear to be associated with atopic conditions of childhood.     

Confirmation of the association between high levels of immunoglobulin E food sensitization and eczema in infancy: an international study

Background Studies of Australian infants have reported that more than 80% of those with moderate atopic eczema (AE) have high levels of IgE food sensitization (IgE‐FS) that are commonly associated with IgE food allergy. Objectives To explore the relationship between high levels of IgE‐FS and AE in a large cohort of young children with eczema participating in a multi‐centre, international study. Methods Two thousand one hundred and eighty‐four subjects (mean age 17.6 months, range 11.8–25.4; 1246 males) with active eczema from atopic families from 94 centres in 12 countries were studied. Clinical history, Scoring Atopic Dermatitis index as a measure of eczema severity and CAP‐FEIA measurements for total IgE and IgE antibody levels to cow milk, egg and peanut were entered into a database. If CAP‐FEIA levels exceeded previously reported age‐specific cut‐off levels for 95% positive predictive values (PPVs) for food allergy, subjects were defined as having high‐risk IgE‐FS (HR‐IgE‐FS). Results Serum was available from 2048 patients; 55.5% were atopic. The frequency of HR‐IgE‐FS to milk, egg and/or peanut was the greatest in patients whose eczema developed in the first 3 months of life and the least in those whose eczema developed after 12 months (P<0.0001). In a regression analysis to allow for potential confounding factors, children with HR‐IgE‐FS had the most severe eczema and the youngest age of onset (P<0.001); 64% of infants with severe eczema of onset‐age <3 months had HR‐IgE‐FS. Conclusion Early‐onset severe eczema in infancy was associated with HR‐IgE‐FS. Clinical implications Food allergies should be routinely assessed in infants with moderate or severe eczema. Capsule summary In eczematous infants, the earlier the age of onset, and the greater the severity of eczema, the greater the frequency of associated high levels of IgE‐FS.     

Lactobacillus casei strain Shirota suppresses serum immunoglobulin E and immunoglobulin G1 responses and systemic anaphylaxis in a food allergy model

BACKGROUND: Our previous study using allergen-sensitized murine splenocyte cultures has shown that Lactobacillus casei strain Shirota (LcS), a lactic acid bacterium widely used as a starter for fermented milk products, suppresses IgE production through promoting a dominant Th1-type response mediated by IL-12 induction. OBJECTIVE: We tried to evaluate the ability of LcS to suppress both IgE response and allergic reactions in vivo using a food allergy model with ovalbumin-specific T cell receptor transgenic (OVA-TCR-Tg) mice. METHODS: The ability of heat-killed LcS to induce IL-12 in serum was tested. OVA-TCR-Tg mice were fed a diet containing OVA for 4 weeks and injected with LcS intraperitoneally three times in the first week of this period. Cytokine and antibody secretion by splenocytes, and serum IgE and IgG1 responses were examined. The inhibitory effect of LcS on systemic anaphylaxis induced by intravenous challenge of OVA-fed OVA-TCR-Tg mice with OVA was also tested. RESULTS: Intraperitoneal injection of LcS induced an IL-12 response in the serum of OVA-TCR-Tg mice. In the food allergy model, LcS administration skewed the pattern of cytokine production by splenocytes toward Th1 dominance, and suppressed IgE and IgG1 secretion by splenocytes. The ability of LcS to modulate cytokine production was blocked by anti-IL-12 antibody treatment. LcS also inhibited serum OVA-specific IgE and IgG1 responses and diminished systemic anaphylaxis. CONCLUSION: LcS administration suppresses IgE and IgG1 responses and systemic allergic reactions in a food allergy model, suggesting a possible use of this lactic acid bacterium in preventing food allergy.     

Low immunoglobulin E flags two distinct types of immune dysregulation

During the last two decades, hyper‐immunoglobulin (Ig)E syndromes have been characterized clinically and molecularly in patients with genetically determined primary immunodeficiencies. However, the detection of low IgE levels, defined here as below detection limit in the routine clinical immunology laboratory, has received little attention. We analysed the association of serum IgA, IgM and IgG levels (including IgG subclasses) with low, normal or high serum IgE levels in patients evaluated in a single‐centre out‐patient immunodeficiency and allergy clinic. The correlation of serum IgE levels with IgG subclasses depended on the clinical phenotype. In patients with immunodeficiencies, IgE correlated with IgG2 and IgG4 but not with IgG3. In contrast, in patients referred for signs of allergy, IgE correlated with IgG3 but not with IgG2. A low IgE result was associated with low IgG3 and IgG4 in allergy referrals, while immunodeficiency referrals with a low IgE result had significantly lower IgG1, IgG2 and IgG4 levels. Hierarchical clustering of non‐IgE immunoglobulin profiles (IgM, IgA, IgG, IgG1–4) validated that non‐IgE immunoglobulin levels predict the clinic referral, i.e. phenotype, of low‐IgE patients. These results suggesto guide the clinical management of patients with low serum IgE levels.     

Local immunoglobulin production in nasal polyposis is modulated by superantigens

Background Chronic rhinosinusitis (CRS) with nasal polyps (NP) represents a persistent inflammation often characterized by local hyper‐immunoglobulinaemia and the presence of specific IgE to Staphylococcus aureus enterotoxins (SAEs). We aimed to study the systemic and local production of Igs in relation to plasma cells, B cells and specific IgE to SAEs. Methods Concentrations of IgE, IgG, IgM, IgA, IgG subclasses and specific IgE to SAE were determined on tissue homogenates and serum from 15 CRS patients with NP, 15 CRS without NP and 10 control patients. Tissue cryo‐sections were stained for CD19, CD20 and CD138 to demonstrate B and plasma cells. Results IgA, IgG and IgE concentrations were significantly higher in tissue homogenates, but not in serum, of NP compared with CRS and control subjects. NP with specific IgE to SAEs had significantly higher concentrations of IgG and IgE, and also showed a significantly higher fraction of IgG4 (P=0.003) and a lower fraction of IgG2 (P=0.04) than those without specific IgE production. Furthermore, naïve CD19⁺ B cell and plasma cell counts (CD138⁺) were significantly higher in NP tissue compared with controls or CRS. Conclusions The difference in IgE, IgG and IgA expression between NP tissue and serum, supported by increased numbers of plasma cells, suggests a local production of these Igs in NP in response to a chronic microbial trigger. The local immune response to SAE is associated with a further increased production of IgE and IgG, and a shift in IgG subclasses.     

Inhibition of CD23‐dependent facilitated allergen binding to B cells following vaccination with genetically modified hypoallergenic Bet v 1 molecules

Background Vaccination with hypoallergenic recombinant Bet v 1 derivatives (Bet v 1 fragments and Bet v 1 trimer) is associated with the induction of IgG antibodies specific to natural Bet v 1. Objective To investigate whether IgG antibodies induced following vaccination with genetically modified hypoallergenic Bet v 1 derivatives are able to inhibit IgE‐facilitated binding of allergen‐IgE complexes to B cells. Methods Sera from 46 patients obtained before and after subcutaneous vaccination with Bet v 1 trimer (n=14), Bet v 1 fragments (n=11) or placebo (n=21) were incubated with recombinant (r) Bet v 1 and an indicator serum (IS) from a birch pollen‐allergic patient with high CD23 binding capacity. Bet v 1 immune complexes were added to a CD23‐expressing B cell line and co‐operative binding of Bet v1‐IgE complexes to CD23 was measured with a polyclonal anti‐IgE FITC antibody using a bio‐functional cellular flow cytometric assay. Results When sera from patients vaccinated with rBet v 1 derivatives were incubated with Bet v 1 and the IS, a reduction of IgE binding to CD23 was observed. This effect was not seen when sera from placebo‐treated patients were used. The decrease in CD23/IgE binding was statistically significant in the trimer group [pre‐ vs. post‐specific immunotherapy (SIT): P=0.02; trimer vs. placebo: P<0.04] but not in the Bet v 1 fragments‐treated group. Trimer‐treated patients had higher levels of Bet v 1‐specific IgG than fragment‐treated patients. The degree of inhibitory activity of IgE‐facilitated allergen binding correlated with Bet v 1‐specific IgG levels following SIT (R=0.492; P=0.012). Conclusion Vaccination with both recombinant Bet v 1 derivatives induces Bet v 1‐specific IgG antibodies, which are able to inhibit the co‐operative binding of allergen‐IgE complexes to CD23, and may thereby reduce allergen‐specific T cell responses. Cite this as: I. Pree, M. H. Shamji, I. Kimber, R. Valenta, S. R. Durham and V. Niederberger, Clinical & Experimental Allergy, 2010 (40) 1346–1352.     

Cow's milk stimulated lymphocyte proliferation and TNFalpha secretion in hypersensitivity to cow's milk protein

Although there is no reliable single laboratory test available for the diagnosis of cow's milk allergy, if an allergic mechanism is suspected, a number of laboratory studies may be useful in delineating specific proteins responsible for these disorders. In the current study we analyzed in vitro lymphocyte proliferation assays, specific secretion of TNFalpha in supernatant cultures and specific IgE, IgG, and IgA in a group of patients with hypersensitivity to cow's milk antigens. The stimulation index against a cow's milk antigen mixture, alpha-lactalbumin, beta-lactoglobulin, and casein was significant higher in the group of patients maintained on cow's milk-free diet for less than 4 months compared with the values observed in the control group and in the group of patients without a close contact to cow's milk proteins. A significant increase in TNF-alpha secretion was observed in supernatants from patients with close contact to cow's milk (CM). Specific IgE was detected in 59.3% of the patients, with higher specific IgE levels in patients who were not positive for the proliferation assay, suggesting a clear difference in the two mechanisms proposed as effectors in this disease. No differences in specific IgG and IgA levels were observed between the patient group and the control group, with a great dispersion among individuals in all groups tested. We conclude that a combination of the assays tested in this study, such as proliferative assay of peripheral blood mononuclear cells to CM, the quantitation of TNFalpha in culture supernatants, and serum specific IgE determination, are useful laboratory tests to identify cow's milk allergy among patients with immediate and non immediate adverse reactions, reducing the need for food allergen challenges in young children.     

Suppression of specific IgE antibody responses by liposome-conjugated ovalbumin in mice sensitized with ovalbumin via the respiratory tract

BACKGROUND: Previously we have shown that intranasal administration of ovalbumin (OVA) together with cholera toxin (CT) abrogates nasal tolerance to OVA, resulting in the induction of specific IgE antibody (Ab) responses, and that intraperitoneal injection of OVA coupled with liposomes (OVA-liposomes) induces a selective suppression of IgE Ab responses to OVA. Whether OVA-liposomes suppress anti-OVA IgE Ab responses in mice sensitized with CT-combined OVA via the respiratory tract remains to be clarified. METHODS: In some experiments, mice were given OVA, liposomes or OVA-liposomes with or without CT intranasally three times, at 2-week intervals (weeks 0, 2 and 4). In other experiments, mice were given OVA-liposomes intranasally 2 days before or 1 and 3 weeks after CT-combined OVA (week 0), which was administered intranasally three times, at 2-week intervals (weeks 0, 2 and 4). Two weeks after the third administration of CT-combined OVA (week 0), nasal wash and serum IgA, IgG and IgE Ab responses were assayed. RESULTS: Pretreatment with OVA-liposomes suppressed IgE Ab responses to CT-combined OVA, with a significantly high production of both nasal IgA and serum IgG Abs. Moreover, treatment with OVA-liposomes 1 and 3 weeks after CT-combined OVA administration also suppressed IgE Ab responses. The suppression of anti-OVA IgE Ab production by OVA-liposomes was accompanied by a simultaneous enhancement of specific IgA and IgG (IgG1, and especially IgG2a) Ab production. CONCLUSIONS: Postimmunization treatment with OVA-liposomes, as well as preimmunization treatment, suppressed specific IgE Ab responses in mice sensitized intranasally with CT-combined OVA. Allergens conjugated to liposomes may be appropriate for preventing the development of allergies to inhaled or dietary antigens in humans.     

Effect of a new synbiotic mixture on atopic dermatitis in infants: a randomized‐controlled trial

Background Clinical trials investigating the therapeutic effect of probiotics on atopic dermatitis (AD) show inconsistent results. Better results can possibly be achieved by combining probiotics with prebiotics, i.e. synbiotics. Objective To investigate the therapeutic effect of a synbiotic mixture on the severity of AD in infants. Methods In a double‐blind, placebo‐controlled multi‐centre trial, 90 infants with AD [SCORing Atopic Dermatitis (SCORAD) score 15], aged <7 months and exclusively formula fed, were randomly assigned to receive either an extensively hydrolysed formula with Bifidobacterium breve M‐16V and a galacto‐/fructooligosaccharide mixture (Immunofortis^®), or the same formula without synbiotics for 12 weeks. The primary outcome was severity of AD, assessed using the SCORAD index. A secondary outcome measure was intestinal microbiota composition. Results There was no difference in SCORAD score improvement between the synbiotic and the placebo group. The synbiotic group did have a significantly higher percentage of bifidobacteria (54.7% vs. 30.1%, P<0.001) and significantly lower percentages of Clostridium lituseburense/Clostridium histolyticum (0.5 vs. 1.8, P=0.02) and Eubacterium rectale/Clostridium coccoides (7.5 vs. 38.1, P<0.001) after intervention than the placebo group. In the subgroup of infants with IgE‐associated AD (n=48), SCORAD score improvement was significantly greater in the synbiotic than in the placebo group at week 12 (?18.1 vs. ?13.5 points, P=0.04). Conclusions This synbiotic mixture does not have a beneficial effect on AD severity in infants, although it does successfully modulate their intestinal microbiota. Further randomized‐controlled trials should explore a possible beneficial effect in IgE‐associated AD. Cite this as: L. B. van der Aa, H. S. Heymans, W. M. van Aalderen, J. H. Sillevis Smitt, J. Knol, K. Ben Amor, D. A. Goossens, A. B. Sprikkelman and the Synbad Study Group, Clinical & Experimental Allergy, 2010 (40) 795–804.