Stepwise approach towards adoption of allergen immunotherapy for allergic rhinitis and asthma patients in daily practice in Belgium: a BelSACI-Abeforcal-EUFOREA statement

Allergic rhinitis (AR) affects 23–30% of the European population with equal prevalence reported in Belgium. Despite guidelines on the correct use of effective treatment, up to 40% of AR patients remain uncontrolled. Allergen immunotherapy (AIT) has been shown to improve the level of control up to 84% of patients being controlled by AIT. Recently, new guidelines for AIT have been published, supporting the clinical evidence for effectiveness of various subcutaneous and sublingual products for AIT in patients who are allergic to airborne allergens. AIT in AR patients not only reduces nasal and/or ocular symptoms but also induces tolerance and has preventive potential. Adoption of AIT into daily clinical practice in Belgium and other European countries is hampered primarily by reimbursement issues of each of the single products but also by several patient- and physician-related factors. Patients need to be better informed about the effectiveness of AIT and the different routes of administration of AIT. Physicians dealing with AR patients should inform patients on tolerance-inducing effects of AIT and are in the need of a harmonized and practical guide that supports them in selecting eligible patients for AIT, in choosing evidence-based AIT products and in following treatment protocols with proven efficacy. Therefore, a stepwise and holistic approach is needed for better adoption of AIT in the real-life setting in Belgium.

Intranasal administration of probiotic Lactobacillus rhamnosus GG prevents birch pollen-induced allergic asthma in a murine model

BACKGROUND

There is an increasing interest in targeted application of probiotic bacteria for prevention and treatment of airway diseases, including allergies. Here, we investigated the beneficial effects of preventive intranasal treatment with probiotics Lactobacillus rhamnosus GG and L. rhamnosus GR-1 in a mouse model of allergic asthma.

METHODS

Lactobacillus rhamnosus was administered intranasally eight times on days 1-4 and 8-11 at 5 × 10⁸  CFU/dose, followed by a 2-week asthma induction protocol with birch pollen extract on alternating days. Effects of preventive treatment were analyzed based on serum antibody levels, bronchoalveolar lavage cell counts, lung histology, lung cytokine levels, and airway hyperreactivity. Colonization and translocation of L. rhamnosus were assessed by bacterial cell counts in nasal mucosa, fecal samples, cervical lymph nodes, and blood. Binding of fluorescent L. rhamnosus to fixed murine nasal mucosal cells and airway macrophages was visualized by fluorescence microscopy.

RESULTS

Transient colonization of the murine upper airways by L. rhamnosus GG was demonstrated and was approximately ten times higher compared to L. rhamnosus GR-1. Marked binding of fluorescent L. rhamnosus GG to murine nasal mucosal cells and airway macrophages was visualized. Preventive treatment with L. rhamnosus GG (but not L. rhamnosus GR-1) resulted in a significant decrease in bronchoalveolar lavage eosinophil counts, lung interleukin-13 and interleukin-5 levels, and airway hyperreactivity. A tendency toward a decrease in serum Bet v 1-specific immunoglobulin G1 was likewise observed.

CONCLUSION

Intranasally administered L. rhamnosus GG prevents the development of cardinal features of birch pollen-induced allergic asthma in a strain-specific manner.

Immunological Alterations in Haemophiliacs Treated with Lyophilized Factor VIII Cryoprecipitate from Volunteer Donors

We studied immune function in Belgian haemophiliacs treated with Factor VIII from volunteer donors. No patient had clinical evidence of immune deficiency. We found a decrease in T-helper cells (p <0.0005), in the ratio of T-helper over T-cytotoxic/ suppressor cells (1.72 ± 0.47 versus 2.24 ± 0.82 in controls, p <0.005) and in lymphocyte responsiveness to mitogens (p <0.05).

These findings could not be linked to the amount of F VIII received over the last year, the time since last F VIII administration, circulating immune complexes (54% positive patients, 7% positive controls, p <0.005), increased ALT levels, antibodies to cytomegalo-virus (85% of the patients, 45% of the controls, p <0.005), antibodies to Epstein-Barr virus, nor to the presence of HLA-DR 5 which was found in 56% of the haemophiliacs (20% of the overall Belgian population, p <0.005).

Either F VIII induces long lasting immunological alterations unrelated to AIDS, or haemophilia is itself associated with such changes.

MP29-02 reduces nasal hyperreactivity and nasal mediators in patients with house dust mite-allergic rhinitis

BACKGROUND

Nasal hyperreactivity (NHR) is an important clinical feature of allergic rhinitis (AR). The efficacy of MP29-02 (azelastine hydrochloride (AZE) and fluticasone propionate [FP]) nasal spray on local inflammatory mediators and NHR in AR is unknown. We tested if MP29-02 decreases inflammatory mediators and NHR in AR and if this effect is due to restoration of nasal epithelial barrier function.

METHODS

A 4-week double-blinded placebo-controlled trial with MP29-02 treatment was conducted in 28 patients with house dust mite (HDM) AR. The presence of NHR was evaluated by measuring reduction in nasal flow upon cold dry air exposure. The effects of AZE ± FP on barrier integrity and airway inflammation were studied in a murine model of HDM-induced NHR and on reduced activation of murine sensory neurons and human mast cells.

RESULTS

MP29-02 but not placebo reduced NHR (P < .0001 vs P = .21), levels of substance P (P = .026 vs P = .941), and β-hexosaminidase (P = .036 vs P = .632) in human nasal secretions. In wild-type C57BL6 mice, the reduction in β-hexosaminidase levels (P < .0001) by AZE + FP treatment upon HDM challenge was found in parallel with a decreased transmucosal passage (P = .0012) and completely reversed eosinophilic inflammation (P = .0013). In vitro, repeated applications of AZE + FP desensitized sensory neurons expressing the transient receptor potential channels TRPA1 and TRPV1. AZE + FP reduced MC degranulation to the same extent as AZE alone.

CONCLUSION

MP29-02 treatment reduces inflammatory mediators and NHR in AR. The effects of AZE + FP on MC degranulation, nasal epithelial barrier integrity, and TRP channels provide novel insights into the pathophysiology of allergic rhinitis.

Programmed cell death-1 expression correlates with disease severity and IL-5 in chronic rhinosinusitis with nasal polyps

BACKGROUND

Programmed cell death-1 (PD-1) is a negative regulator of T-cell responses. Expression of PD-1 and its ligands PD-L1 and PD-L2 in chronic rhinosinusitis with nasal polyps (CRSwNP) is poorly studied.

METHODS

Expression of PD-1, PD-L1, PD-L2, TGF-β, IL-5, and IL-10 mRNA was measured by real-time quantitative PCR on tissue homogenates of patients with CRSwNP (n = 21) and healthy controls (n = 21) and on primary epithelial cells. Disease severity was scored using the Lund-Mackay scores of maxillofacial computed tomography (CT) scans. Expression of PD-1 and PD-L1/L2 was evaluated at the cellular and tissue levels (n = 6) by flow cytometry and immunohistochemistry.

RESULTS

Programmed cell death-1 mRNA expression was increased in tissue homogenates from patients with CRSwNP compared with controls, irrespective of the atopy status. Importantly, expression of PD-1 correlated with the total CT scan scores (r = 0.5, P = 0.02). Additionally, a significant association was found between PD-1 mRNA and expression of IL-5 mRNA in control nasal tissue (r = 0.95, P < 0.0001) and in CRSwNP (r = 0.63, P = 0.002). PD-1 was expressed on different subsets of T cells and CD11b^- dendritic cells. Both PD-1 and its ligands were expressed on primary epithelial cells from control nasal tissue and nasal polyp tissue.

CONCLUSIONS

Higher PD-1 expression was found in CRSwNP than in nasal tissue from controls. This was associated with disease severity and tissue IL-5 expression but unrelated to the patients' atopy status.

Restoring airway epithelial barrier dysfunction: a new therapeutic challenge in allergic airway disease

An intact functional mucosal barrier is considered to be crucial for the maintenance of airway homeostasis as it protects the host immune system from exposure to allergens and noxious environmental triggers. Recent data provided evidence for the contribution of barrier dysfunction to the development of inflammatory diseases in the airways, skin and gut. A defective barrier has been documented in chronic rhinosinusitis, allergic rhinitis, asthma, atopic dermatitis and inflammatory bowel diseases. However, it remains to be elucidated to what extent primary (genetic) versus secondary (inflammatory) mechanisms drive barrier dysfunction. The precise pathogenesis of barrier dysfunction in patients with chronic mucosal inflammation and its implications on tissue inflammation and systemic absorption of exogenous particles are only partly understood. Since epithelial barrier defects are linked with chronicity and severity of airway inflammation, restoring the barrier integrity may become a useful approach in the treatment of allergic diseases. We here provide a state-of-the-art review on epithelial barrier dysfunction in upper and lower airways as well as in the intestine and the skin and on how barrier dysfunction can be restored from a therapeutic perspective.

Low cord blood Foxp3/CD3γ mRNA ratios: a marker of increased risk for allergy development

BACKGROUND

Data from birth cohort studies suggest that increased cord blood total IgE and reduced cord blood regulatory T cells increase the risk of developing allergic sensitization and atopic dermatitis.

OBJECTIVE

We here addressed whether serum total IgE and hen's egg-specific IgE levels at birth and at age 1 year differed between healthy and allergic children in a Belgian birth cohort (FONIA). We furthermore studied whether these parameters as well as cord blood Foxp3/CD3γ mRNA levels might predict the allergic outcome.

METHODS AND RESULTS

Children (n = 84) were clinically assessed at the ages of 6, 12, 18, and 24 months and at 6 years. Cord blood total IgE levels above 0.35 kU/L predicted early (i.e. before or at the age of 2 years) allergy development. Presence of serum IgE antibodies to hen's egg (cut-off 0.05 Ua/mL) at the age of 1 year was associated with early as well as late (i.e. between the age of 2 and 6 years) allergy development. Cord blood Foxp3/CD3γ mRNA ratios were significantly lower in early allergic children and levels below 0.32 predicted the allergic outcome.

CONCLUSIONS AND CLINICAL RELEVANCE

Low cord blood Foxp3/CD3γ mRNA ratios are highly predictive for early allergy development, whereas specific IgE levels to hen's egg white above 0.05 Ua/mL at age 1 year predict allergy development in general.

Damage-associated molecular pattern and innate cytokine release in the airways of competitive swimmers

BACKGROUND

Daily intensive exercise by elite athletes can result in exercise-induced asthma especially in elite swimmers and this may be linked to epithelial damage.

OBJECTIVE

To study airway epithelial damage and release of damage-associated molecular patterns (DAMPs) after intensive exercise in elite athletes and controls.

METHODS

We recruited competitive swimmers (n = 26), competitive indoor athletes (n = 13) and controls (n = 15) without any history of asthma. Lung function was measured before, immediately after and 24 h after a 90-min intensive exercise protocol. Sputum induction was performed at baseline and 24 h after exercise. Exercise-induced bronchoconstriction (EIB) was assessed by the eucapnic voluntary hyperventilation test.

RESULTS

Baseline sputum uric acid, high mobility group box-1, CXCL8 mRNA, sputum neutrophils and serum Clara cell protein-16 (CC-16) were significantly higher in competitive swimmers compared with controls. Intensive swimming for 90 min resulted in an increase of sputum IL-1β, IL-6 and TNF mRNA in competitive swimmers, and of sputum IL-6 mRNA and sputum neutrophils in controls. Although all participants were asymptomatic, seven competitive swimmers, one indoor athlete and one control met the criteria for EIB.

CONCLUSION

Our findings show that the intensive training combined with exposure to by-products of chlorination induces airway epithelial damage in competitive swimmers. This is associated with increased damage-associated molecular patterns, innate cytokine release and neutrophilic airway inflammation.

Perioperative allergic reactions: experience in a Flemish referral centre

BACKGROUND

The incidence of perioperative anaphylactic reactions is overall estimated to be 1 per 10,000-20,000 anaesthetic procedures. We performed a retrospective analysis of patients referred to a University Allergy Centre in Belgium with the suspicion of an allergic reaction during or shortly after general anaesthesia.

OBJECTIVES

Our aim was to assess the causes of perioperative allergic reactions, to evaluate cross-reactivity among neuromuscular blocking agents (NMBA) and to analyze the diagnostic relevance of tryptase levels in the discrimination between IgE and non-IgE-mediated reactions.

METHODS

A total of 119 patients, referred from 2007 to 2011 were included. The diagnostic protocol consisted in case history, serum tryptase measurements, immunoassays and skin tests.

RESULTS

A diagnosis of IgE-mediated reaction was established in 76 cases (63.9%). The most common agents were NMBA (61.8%), antibiotics (14.5%), latex (9.2%) and chlorhexidine (5.2%). Rocuronium was the most frequently causative NMBA (48.9%). Vecuronium cross-reactivity was established by skin testing in 47.6% of cases. Cisatracurium was the NMBA most frequently tolerated (cross-reaction in 13.9%). In 23.4% of NMBA allergic patients, the reaction occurred on the first exposure. Most IgE-mediated reactions occurred during the induction phase (72.4%). Latex-induced reactions occurred mainly during maintenance and recovery phases (71.4%; p<0.02). Mean tryptase values were significantly higher in patients with IgE-mediated reactions (p=0.0001), than in those with no identified cause.

CONCLUSIONS

NMBA, antibiotics, latex and chlorhexidine were the main culprits of IgE-mediated perioperative reactions. Uncertainties remain concerning the specificity and sensitivity of skin testing. Tryptase assays can be useful in the discrimination of IgE and non-IgE-mediated reactions.

Vascular endothelial growth factor receptor 1 expression in nasal polyp tissue

BACKGROUND

Edema represents a key feature of nasal polyp (NP) disease. Members of the vascular endothelial growth factor (VEGF) family may be involved, but the precise role of VEGF-A, VEGF-B, placental growth factor (PlGF), and their receptors VEGFR1 and VEGFR2 in NP edema formation remains elusive.

OBJECTIVE

Exploring the expression of VEGF family members and their receptors and their correlation with clinical, radiological, and edema markers in NP.

METHODS

The expression of VEGF-A, VEGF-B, PlGF, VEGFR1, and VEGFR2 was measured in NP (n = 23) and control tissue (n = 22) at mRNA and protein level. Edema was evaluated by measuring albumin levels and wet/dry ratios. Computed tomography (CT) scans were scored using the Lund-Mackay scoring system. IL-5 mRNA expression was determined by real-time RT-PCR. Cell suspensions from NP (n = 10) and control tissue (n = 12) were stimulated in vitro with IL-1β or TNFα.

RESULTS

mRNA expression of VEGFR1 and VEGF-B was significantly higher in NP compared with control tissue. Expression levels of VEGF-B and VEGFR1 significantly correlated with NP albumin content (VEGF-B: P = 0.0208; VEGFR1: P = 0.0293), CT scan scores (VEGF-B: P = 0.0075; VEGFR1: P = 0.0068), and IL-5 mRNA (VEGF-B: P = 0.0027; VEGFR1: P = 0.0001). In vitro stimulation of control and NP tissue cell suspensions with IL-1β or TNFα significantly reduced the expression of VEGFR2 in control tissue, without altering VEGFR1 and VEGF-B expression. hVEGF-B induced nitric oxide production in NP macrophages (P < 0.05).

CONCLUSION

Expression levels of VEGFR1 and VEGF-B correlate with edema and clinical markers of NP disease and therefore represent potential therapeutic targets.

Effects of haptoglobin polymorphisms and deficiency on susceptibility to inflammatory bowel disease and on severity of murine colitis

BACKGROUND

Haptoglobin (Hp) is a haemoglobin-binding protein with immunomodulatory properties. Its gene (16q22) harbours a common polymorphism with two different alleles: Hp1 and Hp2. Genotype Hp22 has been shown to be over-represented in different immune diseases. Results in Crohn's disease (CD) are contradictory.

AIMS

To determine whether Hp plays a role in inflammatory bowel disease, both genetically and functionally.

METHODS

1061 patients with CD, 755 with ulcerative colitis (UC) and 152 with primary sclerosing cholangitis, as well as 452 healthy controls, were genotyped using touch-down PCR. To confirm association results, 464 CD trios and 151 UC trios were genotyped. Serum Hp concentrations were determined in 62 individuals of different genotype. Colitis was induced in mice with dextran sulphate sodium (DSS) and oxazolone (Oxa). Cytokine production was evaluated by mRNA quantification in colonic tissue and ELISA on supernatants of mesenteric lymph node cells.

RESULTS

Prevalence of Hp2 was higher in CD and UC than in controls. In the confirmatory cohorts, Hp2 was over-transmitted to the affected offspring. Serum Hp concentrations were higher in individuals with genotypes Hp11 and Hp21 than in those with Hp22 (1.38 vs 0.89 g/l). DSS- and Oxa-induced colitis were more severe in Hp-deficient mice than in control mice and accompanied by higher concentrations (although not statistically significantly different) of tissue mRNA for cytokines. Interleukin-17 production was significantly higher in the presence of Hp-deficient serum compared with wild-type serum.

CONCLUSIONS

The Hp gene may play a role in susceptibility to inflammatory bowel disease. Its implication in other immune diseases underscores the common pathways between these diseases. Experimental models of colitis showed that Hp has a protective role in inflammatory colitis, most likely by inhibiting the production of Th1 and Th17 cytokines.

Conjunctival effects of a selective nasal pollen provocation

BACKGROUND

Several clinical and experimental observations suggest that allergen deposition in the nose may partially be responsible for the induction of conjunctival symptoms in allergic rhinitis. The aims of this study were to evaluate the induction of conjunctival symptoms by selective nasal allergen provocation and to assess the feasibility of the different tools for evaluation of conjunctival allergic inflammation.

METHODS

Grass pollen allergic subjects with rhinoconjunctivitis symptoms during the pollen season (n = 12) underwent a nasal sham and grass pollen provocation extra-seasonally. Nasal and conjunctival symptoms were scored using the Visual Analogue Scale (VAS) system at baseline, 15 min, 1 h and 24 h after provocation. In addition to Peak Nasal Inspiratory flow (PNIF) measurements, conjunctival inflammation and vascular congestion were evaluated and histamine and substance P levels in tear fluid were measured.

RESULTS

Selective nasal grass pollen provocation induced ocular pruritus, lacrimation and conjunctival vascular congestion. PNIF values correlated inversely with lacrimation (r = -0.71, P < 0.001) and ocular pruritus (r = -0.41, P < 0.05). Four out of 11 patients showed a conjunctival eosinophilic inflammation and levels of histamine (r = 0.73, P < 0.05) and substance P (r = 0.67, P = 0.05) in tear fluid correlated with conjunctival symptoms.

CONCLUSION

Selective nasal grass pollen provocation induced conjunctival inflammation, ocular pruritus and lacrimation, which correlated with histamine and substance P levels in tear fluid and inversely with the PNIF values. These data show a naso-ocular interaction in allergic rhinitis and offer objective tools for evaluation of conjunctival inflammation in allergic rhinoconjunctivitis.

Impact of lipoteichoic acid modification on the performance of the probiotic Lactobacillus rhamnosus GG in experimental colitis

While some probiotic strains might have adjuvant effects in the therapy for inflammatory bowel diseases (IBD), these effects remain controversial and cannot be generalized. In this study, a dltD mutant of the model probiotic Lactobacillus rhamnosus GG (LGG), having a drastic modification in its lipoteichoic acid (LTA) molecules, was analysed for its effects in an experimental colitis model. Dextran sulphate sodium (DSS) was used to induce either moderate to severe or mild chronic colitis in mice. Mice received either phosphate-buffered saline (PBS), LGG wild-type or the dltD mutant via the drinking water. Macroscopic parameters, histological abnormalities, cytokine and Toll-like receptor (TLR) expression were analysed to assess disease activity. LGG wild-type did not show efficacy in the different experimental colitis set-ups. This wild-type strain even seemed to exacerbate the severity of colitic parameters in the moderate to severe colitis model compared to untreated mice. In contrast, mice treated with the dltD mutant showed an improvement of some colitic parameters compared to LGG wild-type-treated mice in both experimental models. In addition, treatment with the dltD mutant correlated with a significant down-regulation of Toll-like receptor-2 expression and of downstream proinflammatory cytokine expression in the colitic mice. These results show that molecular cell surface characteristics of probiotics are crucial when probiotics are considered for use as supporting therapy in IBD.

Staphylococcus aureus enterotoxin B augments granulocyte migration and survival via airway epithelial cell activation

BACKGROUND

Staphylococcus aureus enterotoxin B (SEB) has recently been postulated to be involved in the pathology of granulocyte-dominated disease. Studying the immunologic interaction between SEB and airway epithelial cells in immortalized cell lines or long-term epithelial cell cultures has obvious disadvantages.

METHODS

We used a novel technique of freshly isolated and purified human nasal epithelial cells (HNEC) from healthy, nonallergic individuals, which were incubated for 24 h without/with SEB at different concentrations. Chemokine production was evaluated in the supernatant using Cytometric Bead Array. The chemotactic activity of the supernatant was studied in vitro using a Boyden chamber. Survival was evaluated with flow cytometry, using propidium iodide to identify dead cells.

RESULTS

Staphylococcus aureus enterotoxin B showed a dose-dependent induction of interferon-inducible protein-10, monokine induced by interferon-gamma, regulated upon activation normal T cell expressed and secreted, monocyte chemoattractant protein 1 (MCP-1) and granulocyte colony stimulating factor production by epithelial cells in vitro. The supernatant of epithelial cells had chemotactic activity for granulocytes in vitro, which was enhanced in the supernatant of SEB-stimulated epithelial cells. Reduced number of propidium iodide positive granulocytes was found in the conditions where supernatant of SEB-stimulated epithelial cells was applied.

CONCLUSION

Staphylococcus aureus enterotoxin B exerts a direct pro-inflammatory effect on HNEC, with induction of chemokine and growth factor release, resulting in the migration and prolonged survival of granulocytes in vitro.

Staphylococcus aureus enterotoxin B facilitates allergic sensitization in experimental asthma

BACKGROUND

Staphylococcus aureus Enterotoxin B (SEB) has immunomodulatory effects in allergic airway disease. The potential contribution of SEB to the sensitization process to allergens remains obscure.

OBJECTIVE

In order to study the effects of staphylococcal-derived toxins on the sensitization to ovalbumin (OVA) and induction of allergic airway inflammation, we have combined the nasal application of OVA with different toxins.

METHODS

Nasal applications of OVA and saline, SEA, SEB, toxic shock syndrome toxin (TSST)-1, protein A or lipopolysaccharide (LPS) were performed on alternate days from day 0 till 12. On day 14, mice were killed for the evaluation of OVA-specific IgE, cytokine production by mediastinal lymph node (MLN) cells and bronchial hyperreactivity (BHR) to inhaled metacholine. The effect of SEB on dendritic cell (DC) migration and maturation, and on T cell proliferation was evaluated.

RESULTS

Concomitant endonasal application of OVA and SEB resulted in OVA-specific IgE production, whereas this was not found with SEA, TSST-1, protein A, LPS or OVA alone. Increased DC maturation and migration to the draining lymph nodes were observed in OVA/SEB mice, as well as an increased T cell proliferation. Bronchial inflammation with an influx of eosinophils and lymphocytes was demonstrated in OVA/SEB mice, together with hyperresponsiveness and the production of IL-4, IL-5, IL-10 and IL-13 by MLN stimulated with OVA.

CONCLUSIONS

Our data demonstrate that SEB facilitates sensitization to OVA and consecutive bronchial inflammation with features of allergic asthma. This is likely due to augmentation of DC migration and maturation, as well as the allergen-specific T cell proliferation upon concomitant OVA and SEB application.

Immune dysfunction in patients with functional gastrointestinal disorders

There is increasing evidence for involvement of the immune system in functional gastrointestinal disorder (FGID), including onset after acute gastrointestinal infections, genotypes resulting in altered cytokine expression and abnormal presence of immune cells. Our aim was to assess cellular and humoral immune responses in (i) FGIDs, compared to healthy subjects and (ii) acute vs unspecified onset FGIDs. Lymphocytic [interleukin (IL)-5, IL-10, IL-13 and interferon gamma (IFN-gamma)] and monocytic [IL-10, IL-12, tumour necrosis factor (TNF)-alpha] cytokine production was characterized at baseline and after stimulation with phytohemagglutinine and anti-CD28 or lipopolysaccharide (LPS) in controls (n = 32), irritable bowel syndrome (IBS) (n = 30), functional dyspepsia (FD) (n = 23) and non-cardiac chest pain (NCCP) (n = 15). Serum IL-6 and IL-10 concentrations were compared, and the immunophenotype was assessed using fluorescent-activated cell sorter. Findings were compared for acute vs unspecified onset FGID. Compared to controls, stimulated lymphocyte expression of IL-5 and IL-13 was enhanced in IBS, FD and NCCP (all P < 0.05). Conversely, the stimulated monocytic IL-12 and lymphocytic IL-10 expression were reduced in IBS and FD, while IFN-gamma expression was also reduced in FD patients. Except for an increase in the numbers of CD3(+)CD45RA(+)CD45RO(+) cells, no distinct cellular profile was detected. Patients with a presumed acute onset of their symptoms had higher serum IL-10 levels and more CD3(+)CD45RA(+)CD45RO(+) cells, while TNF-alpha levels following stimulation with LPS were higher in FD patients reporting an acute onset. A shift towards a Th2 cytokine profile is present in FGID, while the cellular immunophenotype remains largely unchanged. Further research is indicated and could provide new therapeutic strategies for these disorders.

Type III IFN-lambda mRNA expression in sputum of adult and school-aged asthmatics

BACKGROUND

The increased susceptibility of asthmatics to rhinovirus infection has recently been related to deficient IFN-lambda 1 (IL-29) and IFN-lambda 2/3 (IL-28) production by bronchial epithelial cells and macrophages.

OBJECTIVES

Here, we studied IFN-lambda mRNA expression in the airways of stable asthmatics in comparison with healthy subjects and in relation to asthma symptoms, non-invasive parameters of airway inflammation and lung function parameters.

METHODS

Airway cells were obtained by sputum induction, in 14 healthy and 35 asthmatic adults and 12 asthmatic school-aged children. IFN-lambda was studied at the mRNA level by quantitative RT-PCR.

RESULTS

Asthmatic adults have increased sputum IL-28 mRNA but similar IL-29 mRNA expression in comparison with healthy subjects. In asthmatics, both sputum IL-28 and IL-29 mRNA expression correlate with the sputum CD3 gamma mRNA expression (reflecting infiltrated T cells). IL-28 (but not IL-29) mRNA levels correlate with the relative and absolute number of eosinophils present in the sputum sample. Sputum IL-29 mRNA (but not IL-28) correlates negatively with asthma symptoms in steroid-naive patients and is significantly higher in steroid-treated than in steroid-naive patients. Finally, both IL-28 and IL-29 mRNA levels are higher in asthmatic children than in asthmatic adults.

CONCLUSION

Our results show that asthmatic subjects have substantial type III IFN-lambda mRNA levels in the airways. Our data furthermore suggest that IL-29 could have an immunoprotective role in the lower airways.

Sinonasal pathology in nonallergic asthma and COPD: 'united airway disease' beyond the scope of allergy

BACKGROUND

In contrast to the epidemiological and clinical association between allergic rhinitis and asthma, upper airway inflammation is less characterized in patients with nonatopic asthma and virtually unexplored in chronic obstructive pulmonary disease (COPD). Here, sinonasal pathology is studied in patients with allergic asthma, nonallergic asthma and COPD.

METHODS

Ninety patients with stable bronchial disease were included in the study, of which 35 were diagnosed with allergic asthma, 24 with nonallergic asthma and 31 with COPD. Concurrently, 61 control subjects without pulmonary disease were included and matched for age and smoking habits respectively with the asthma and the COPD group. Sinonasal symptoms were evaluated on a visual analogue scale and rhinosinusitis-related impairment of quality of life was assessed with the sino-nasal outcome test-22 (SNOT-22) questionnaire. Nasal mucosal abnormalities were quantified with nasal endoscopy and nasal secretions collected for measuring inflammatory mediators.

RESULTS

Allergic asthmatics, nonallergic asthmatics and COPD patients reported more nasal symptoms than their respective control subjects, had a higher SNOT-22 score and presented more mucosal abnormalities in the nose. Nasal secretions of both allergic and nonallergic asthmatics contained higher levels of eotaxin, G-CSF, IFN-gamma and MCP-1 than controls. Allergic asthmatics had higher nasal IP-10 levels as well. COPD-patients had higher nasal levels of eotaxin, G-CSF and IFN-gamma than controls.

CONCLUSION

Patients with allergic and nonallergic asthma and COPD show increased nasal symptoms and more nasal inflammation. Hence, our data confirm the 'united airways' concept to be beyond the scope of allergic asthma.

Diagnosis and natural course of allergy to cooked potatoes in children

BACKGROUND

Allergy to heat stable potato proteins can cause severe allergic disease in children.

OBJECTIVE

To study diagnostic criteria for allergy to cooked potatoes and to describe its clinical characteristics and natural history.

METHODS

Thirty-six children, aged 4-36 months, with atopic symptoms and having a positive potato-CAP and/or skin prick test (SPT) were included. Potato allergy was documented by means of provocation, or elimination and reintroduction or an unequivocal clinical history. Potato-CAP and SPT with a commercial extract were evaluated for diagnostic performance.

RESULTS

Presenting symptoms in children with proven potato allergy (n = 17) were eczema (16 of 17), gastrointestinal complaints (eight of 17), urticaria and/or angioedema (five of 17), wheezing/rhinitis (three of 17) and anaphylaxis (two of 17). Fifteen children had previously diagnosed cow's milk protein allergy and were egg-sensitized. Potato-CAP at cut-off >2 kU/l provided a 100% sensitivity and a 62.5% specificity for diagnosis of potato allergy, while a SPT score >/= 3 had a 100% sensitivity and a score >/= 4 had a 100% specificity. Tolerance to cooked potato was achieved in 80% of subjects at age 16-102 months. Of 12 subjects having reached the age of 3 years during the study, 10 were re-evaluated at age 3-6 years: seven of 10 subjects had developed clinical pollen allergy, compared with four of 18 atopic controls (P < 0.05).

CONCLUSIONS

Potato-CAP and SPT at specific cut-off are valuable tools in the diagnosis of allergy to cooked potato. Most children with potato allergy develop tolerance at mean age of 4 years. Allergy to cooked potatoes is a risk factor for the development of pollen allergy.

Aggravation of bronchial eosinophilia in mice by nasal and bronchial exposure to Staphylococcus aureus enterotoxin B

BACKGROUND

The role of bacterial enterotoxins like Staphylococcus aureus enterotoxin B (SEB) in allergic asthma remains unknown. We used a mouse model of airway allergy to study the effects of nasal or bronchial contact with SEB on bronchial allergic inflammation.

METHODS

The features of allergic asthma were induced in ovalbumin (OVA)-sensitized mice (days 1-13) by repeated exposures to nebulized OVA (days 33-37). Nasal or bronchial application of SEB was performed on three occasions (days 33-35-37), and the effects on bronchial inflammation, IgE titres and expression levels of mRNA for T helper type 2 cytokines and other inflammatory mediators were evaluated.

RESULTS

Both nasal and bronchial SEB enhanced the allergen-induced bronchial inflammation, as reflected by more eosinophilic inflammation in the airway lumen and in bronchial tissue. Aggravation of experimental asthma correlated with higher expression of mRNA for IL-5, IL-4, IFN-gamma, IL-12 p40, eotaxin-1 and TGF-beta in bronchi. In addition, nasal SEB elevated concentrations of IL-4, IL-5 and IFN-gamma in serum and bronchial SEB increased titres of OVA-specific and total IgE in serum.

CONCLUSION

Our data illustrate the potential of both nasal as well as bronchial SEB to aggravate several features of allergic asthma in a mouse model.

Involvement of 4-1BB (CD137)-4-1BBligand interaction in the modulation of CD4 T cell-mediated inflammatory colitis

4-1BB ligand (4-1BBL) expressed on antigen-presenting cells interacts with 4-1BB on activated T cells (especially CD8+ cells) and co-stimulates the latter to secrete cytokines and to proliferate. The role of 4-1BB-4-1BBL interaction was studied here in a model of colitis based on naive CD4+ T cell transfer to SCID mice, a disease model in which CD8 cells do not take part. We found that CD4+ T cells from 4-1BB-deficient mice, after transfer in SCID mice, proliferated more rapidly compared to wild-type CD4+ T cells. Mice reconstituted with naive CD4+ T cells from 4-1BB-deficient mice developed colitis, however, with a mixed Th1/Th2 response, in contrast to the Th1-type response in mice reconstituted with wild-type naive CD4+ T cells. Importantly, this altered cytokine response did not temper colitis severity. Although it has been reported previously that 4-1BB co-stimulation may contribute to regulatory T cell functioning, we found that CD4+CD25+ regulatory T cells from 4-1BB-deficient mice were perfectly able to prevent naive CD4+ T cell-induced colitis. In conclusion, our data provide evidence that 4-1BB-4-1BBL interaction modulates the effector CD4+ T cell-driven immune response and cytokine production in experimental colitis without affecting regulatory T cell function.

Evaluation of airway inflammation by quantitative Th1/Th2 cytokine mRNA measurement in sputum of asthma patients

BACKGROUND

Asthma is a chronic inflammatory disorder of the airways driven by T cell activation. Th2 cells and their cytokines are thought to play a role in the pathophysiology of allergic as well as non-allergic asthma.

METHODS

Airway cells were obtained by sputum induction from 15 healthy and 39 asthmatic individuals and the airway T cell cytokine profiles (interleukin (IL)-4, IL-5, IL-13, IL-10 and interferon (IFN)-gamma) at the mRNA level were studied by real time RT-PCR.

RESULTS

Asthma patients had increased expression of IL-5 (p = 0.001) and IL-13 (p = 0.03) mRNA in sputum compared with non-asthmatic controls. IL-4 mRNA and IFN-gamma mRNA were detectable in the sputum of 44% and 21% of patients, respectively, but not in controls. Sputum IL-10 mRNA levels did not differ significantly between patients and controls. Sputum mRNA expression levels of IL-4, IL-5, and IL-13 were significantly correlated with the percentage of eosinophils and were higher in subjects with allergic asthma than in those with non-allergic asthma (p = 0.03, p = 0.02 and p = 0.0002, respectively); they did not differ between mild asthmatic subjects and those with moderate to severe asthma. In contrast, IFN-gamma mRNA expression was higher in non-allergic than in allergic patients (p = 0.04) and higher in patients with moderate to severe asthma than in those with mild asthma (p<0.01). Sputum IL-5 mRNA levels (but not the other cytokine mRNA levels) were also correlated with exhaled nitric oxide (eNO) and with bronchial hyperreactivity expressed as the histamine concentration resulting in a 20% decrease in forced expiratory volume in 1 second.

CONCLUSION

Real time RT-PCR analysis of mRNA in induced sputum confirms a predominance of Th2 cytokines in both allergic and non-allergic asthma. IL-5 levels reflect eosinophil infiltration as well as eNO levels and hyperreactivity, and levels of the Th1 cytokine IFN-gamma indicate asthma severity. The technique is a promising tool for use in further studies of asthma severity and disease activity.

House dust mite-specific T cells in healthy non-atopic children

BACKGROUND

T-helper type 2 (Th2) cells play an important role in the pathogenesis of allergic diseases. Recent studies have demonstrated that allergen-specific T cells can also be found in the blood of healthy individuals. Both IL-10 and IFN-gamma might modulate the induction and maintenance of allergen-specific tolerance.

AIM

To study the phenotype and functional characteristics of allergen-specific T cells in healthy non-atopic children.

METHODS

Peripheral blood mononuclear cells (PBMC) from 13 symptomatic house dust mite (HDM)-allergic children and from nine matched healthy control children were stimulated with recombinant (r)Der p 2, a major allergen from HDMs.

RESULTS

Stimulation with rDer p 2 resulted in Th2 cytokine production in cultures of PBMC from allergic but not from healthy children. In contrast, IL-10 and IFN-gamma were induced in PBMC cultures from both healthy and HDM-allergic children. Intracellular staining revealed that IL-10 and IFN-gamma are largely produced by the same T cells. Stimulation of T cells from healthy children with rDer p 2 also induced expression of inducible costimulator (ICOS) on a small T cell subset.

CONCLUSION

Allergen-specific memory T cells from healthy non-atopic children produce IL-10 and IFN-gamma (but not Th2 cytokines) and express ICOS upon stimulation. These cells might be responsible for a normal immune balance after allergen encounter in non-atopics.

Safety and tolerability of antagonist anti-human CD40 Mab ch5D12 in patients with moderate to severe Crohn's disease

BACKGROUND

The ligation of CD40 by CD154 is a critical step in the interaction between APC and T cells. In animals, antagonizing CD40L-CD40 has been shown to reduce the severity of several autoimmune and inflammatory disorders, including experimental colitis.

AIM

To investigate tolerability and safety of an antagonist chimeric monoclonal anti-human CD40 antibody (ch5D12) for treatment of Crohn's disease.

METHOD

ch5D12 was administrated to 18 patients with moderate to severe Crohn's disease in a single dose, open-label dose-escalation phase I/IIa study.

RESULTS

ch5D12 plasma concentrations increased dose-dependently after infusion. Two patients developed an anti-ch5D12 antibody response. Overall response and remission rates were 72 and 22%, respectively with no evidence for a dose-response effect. Treatment with ch5D12 reduced microscopic disease activity and intensity of the lamina propria cell infiltrate, but did not alter percentages of circulating T and B cells. ch5D12 was well tolerated, although some patients experienced headache, muscle aches, or joint pains, which may have been related to the study drug.

CONCLUSIONS

Antagonizing CD154-CD40 interactions with ch5D12 is a promising therapeutic approach for remission induction in Crohn's disease.

Adalimumab induces apoptosis of human monocytes: a comparative study with infliximab and etanercept

BACKGROUND

Adalimumab, a fully human monoclonal antibody to tumour necrosis factor, was recently introduced for therapy of Crohn's disease.

AIM

Since induction of apoptosis of inflammatory cells is thought to be an important mechanism of action of the antitumour necrosis factor monoclonal antibody infliximab, we studied the induction of apoptosis of activated peripheral blood monocytes by adalimumab.

METHOD

Apoptosis was analysed at the levels of the cell membrane, mitochondria and DNA by flow cytometry.

RESULTS

We found that both adalimumab and infliximab induced apoptosis in cultured monocytes, while etanercept did not. Apoptosis induction was caspase-dependent and detectable already after 2 h. The production of interleukin-10 and interleukin-12 by monocytes was down-regulated significantly by adalimumab and infliximab but not by etanercept, while levels of soluble tumour necrosis factor in monocyte cultures were down-regulated by all three reagents.

CONCLUSIONS

These data show that both adalimumab and infliximab affect monocyte cytokine production and induce apoptosis of activated monocytes. Our findings will have to be further correlated to therapeutic efficacy of these antitumour necrosis factor reagents.

Allergen-specific T cells from birch-pollen-allergic patients and healthy controls differ in T helper 2 cytokine and in interleukin-10 production

BACKGROUND

T helper (Th)2 cells play an important role in the development of IgE-mediated diseases, with local overproduction of Th2 cytokines (IL-4, IL-5 and IL-13) at the site of allergic inflammation. Furthermore, IL-10 has been suggested to play a modulatory role in the induction and maintenance of allergen-specific tolerance in human atopic diseases.

AIM

We studied whether circulating allergen-specific Th2 cells persist outside the season of exposure in patients mono-sensitized to birch pollen and whether healthy control individuals also have allergen-specific Th2 cells. We also studied whether IL-10-producing allergen-specific T cells can be found in circulation either in healthy controls or in allergic patients.

METHODS

Blood was drawn outside the birch-pollen season from 15 birch-pollen-allergic patients, with seasonal respiratory symptoms and with (n=12) or without (n=3) oral allergy syndrome, and from 10 matched healthy controls. Peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with recombinant Bet v 1 allergen, control antigen tetanus toxoid (TT) and anti-CD3/CD80. In part of the cultures, rIL-4 was added in order to reinforce the allergen-specific Th2 cell responses.

RESULTS

In the presence of rBet v 1, T cells from allergic patients, but not from healthy controls, produced IL-4, IL-5 and IL-13. IL-5 production by patients' T cells was further enhanced by adding more IL-4. In contrast, rBet v 1 together with IL-4-induced significant IL-10 production in control subjects but not in patients. Both Th1 and Th2 cytokines were equally induced by polyclonal stimulation in allergic patients and controls, but in the presence of IL-4, polyclonally induced IL-10 production was lower in the patient group.

CONCLUSION

rBet v 1-specific Th2 cells circulate outside the season of exposure in the blood of birch-pollen-allergic subjects but not in healthy controls. Allergen-specific T cells were also demonstrated in controls but these cells produce IL-10 when stimulated with rBet v 1 in the presence of IL-4. Our data reveal a different allergen-induced cytokine profile in birch-pollen-allergic patients vs. controls, and suggest that a regulatory mechanism involving IL-4-induced allergen-specific IL-10 production might be defective in allergic subjects.

Mouse models of global airway allergy: what have we learned and what should we do next?

Recent epidemiological and clinical data indicate that allergic rhinitis and asthma coexist and should be considered as one airway allergy syndrome. In spite of the importance of this new concept of global airway allergy, it has not fundamentally changed our daily diagnostic and therapeutic strategies so far because of the lack of essential clues to understand the correlation between allergic inflammation in upper and lower airways. Because of the resemblance of experimentally induced allergic airway inflammation in mice to inflamed airways of allergic patients, mouse models can enhance our insight into mechanisms underlying the global airway allergy syndrome. We here review data generated in mice that are relevant for understanding the development of airway allergy and provide new options for research on the so-called 'united airway disease'.

The circulating lymphocyte profiles in patients with discoid lupus erythematosus and systemic lupus erythematosus suggest a pathogenetic relationship

BACKGROUND

Discoid lupus erythematosus (DLE) and systemic lupus erythematosus (SLE) are chronic inflammatory diseases of unknown aetiology; the relationship of DLE with SLE has been a subject of debate for many years. OBJECTIVES; To find evidence for systemic immune activation in DLE by analysis of the immunophenotypic profiles of circulating lymphocytes, and to compare these changes with those in patients with SLE.

METHODS

The immunophenotypic profile of peripheral blood lymphocyte subsets from 23 DLE patients without clinical or laboratory evidence of systemic disease, 25 SLE patients and 38 healthy donors was characterized by two-colour immunofluorescence flow cytometry analysis. None of the patients was receiving corticosteroid or immunosuppressive treatment.

RESULTS

Patients with DLE had increased numbers of circulating HLA-DR+ CD3+ T cells and HLA-DR+ CD4+ T cells, indicating systemic T-cell activation, and an expansion of CD5+ CD19+ B cells. Decreased numbers of T-cell subsets expressing the differentiation markers CD11b and CD16/56, and of CD16/56+ natural killer cells were also found. In SLE, the changes were similar but more pronounced. In addition, a profound CD4+ T-cell lymphopenia and an increase of HLA-DR+ CD8+ T cells were found only in SLE.

CONCLUSIONS

Our data provide evidence for systemic activation of the cellular immune system in patients with purely cutaneous DLE. Similarities in the lymphocyte immunophenotypic profiles in patients with DLE compared with SLE suggest that there are common immunopathological processes in these two conditions.

Inhibition of costimulation allows for repeated systemic administration of adenoviral vector in rhesus monkeys

Immunogenicity of recombinant adenoviral (Ad) vectors severely hampers the clinical development of gene therapy protocols using repeated vector administrations. Inhibition of costimulation by APCs was explored as a strategy to circumvent the immune response against Ad particles. This strategy was tested in rhesus monkeys, treated transiently with chimeric anti-human CD40 and anti-human CD86 antagonist monoclonal antibodies (MAbs) at the time of systemic administration of a recombinant Ad vector. After Ad vector administration in the absence of immunosuppressive treatment, transgene expression in the serum lasted about 3-4 weeks. All control animals developed a strong neutralizing antibody (NAb) response to the Ad particles, which totally prevented efficient administration of a second vector, as shown by the lack of transgene expression. Treatment with anti-CD40 and anti-CD86 chimeric MAbs delayed or blocked the development of a humoral response against Ad and the infiltration of CD8(+) lymphocytes into the liver. This resulted in (i) increased persistence of Ad-transduced cells after injection of a first vector encoding a nonimmunogenic transgene, and (ii) the possibility of readministering a second Ad vector with significant efficacy. In both respects, the combined blockade of CD40 and CD86 was more efficient than treatment with anti-CD40 alone. This study shows for the first time in non-human primates that blocking CD40 and CD86 costimulatory molecules represents a promising strategy to inhibit immune responses against an Ad vector injected systemically.

Blocking B7 and CD40 co-stimulatory molecules decreases antiviral T cell activity

Inhibition of co-stimulatory signals for T cells by interrupting CD80/CD86-CD28 and CD40-CD154 interactions is a promising approach to prevent transplant rejection and to induce graft tolerance. However, this tolerizing treatment might affect T cell reactivity towards all the antigens to which the immune system is exposed during treatment. We addressed the question whether such inhibition of co-stimulatory ligands on human antigen presenting cells (APC) would affect T cell reactivity against a virus. This was tested in an in vitro system with freshly isolated human monocytes transduced with adenovirus (ad) containing either murine interferon-gamma (mIFN-gamma) or green fluorescent protein (GFP) as marker transgene. T cells co-cultured with transduced monocytes proliferated and produced cytokines. These 'primed' T cells had strong antiviral activity as they subsequently killed ad/GFP-transduced monocytes and reduced mIFN-gamma accumulation in coculture with ad/mIFN-transduced monocytes. However, if priming had occurred in the presence of blocking anti-CD40/CD80/CD86 MoAbs, generation of this antiviral activity was completely prevented. Moreover, T cells primed in the absence of co-stimulatory cells failed to proliferate upon restimulation with adenovirus-transduced monocytes. The results confirm that co-stimulatory signals from APC are required for efficient induction of antiviral T cell activity and point to a potential infectious risk of blocking co-stimulatory signals.

Involvement of interleukin 18 in Crohn's disease: evidence from in vitro analysis of human gut inflammatory cells and from experimental colitis models

An imbalance of immunoregulatory factors and/or cells contributes to uncontrolled mucosal T cell activation and inflammation in Crohn's disease (CD). Bioactive interleukin (IL)-18 has been shown to be produced by macrophages in CD lesions. We report here that T cells freshly isolated from inflamed tissue of CD patients (and not T cells from control intestinal tissue) were responsive to IL-18. In the presence of IL-18, these T cells produced more interferon (IFN)-gamma and less IL-10. To analyse further the role of IL-18 in this disease, an acute and a chronic model of murine colitis were used. IL-18 mRNA was significantly enhanced in trinitrobenzene sulphonic acid (TNBS) induced colitis, and treatment with IL-18 binding protein (IL-18BPa), which neutralizes IL-18 bioactivity, significantly reduced the severity of colitis. However, IL-18BPa did not affect the course of chronic colitis in CD45RBhighCD4+ T cell reconstituted SCID mice. Production of IFN-gamma in lamina propria mononuclear cell cultures from IL-18BPa-treated SCID mice was decreased, but at the same time fewer lamina propria CD4+ T cells harvested from IL-18BPa-treated mice compared to non-treated mice were in apoptosis. We conclude that IL-18 clearly has a modulatory role in the inflammatory cascade of CD and experimental colitis by affecting IFN-gamma and IL-10 production, and apoptosis. In view of the divergent effects of IL-18 neutralization in the two different murine colitis models, it is unlikely that IL-18 is at the top of this cascade.

Progesterone increases airway eosinophilia and hyper-responsiveness in a murine model of allergic asthma

BACKGROUND

Sex hormones might affect the severity and evolution of bronchial asthma. From existing literature, there exists, however, no convincing evidence for either exacerbation or improvement of allergic symptoms by progesterone.

OBJECTIVE

This study was aimed to explore the effect of exogenously administered progesterone in a mouse model of allergic asthma.

METHODS

BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injections with OVA followed by chronic inhalation of nebulized OVA or physiologic saline (Sal). Medroxyprogesterone acetate or placebo was instilled daily into the oesophagus before and during the inhalatory OVA challenge phase.

RESULTS

Progesterone worsened allergic airway inflammation in OVA-challenged mice, as evidenced by enhanced bronchial responsiveness to inhaled metacholine and increased bronchial eosinophilia. Elevated airway eosinophilia corresponded with higher bronchial and systemic IL-5 levels in the progesterone group. The ratio of IL-4/IFN-gamma levels in bronchoalveolar lavage fluid and numbers of eosinophil colony-forming units in the bone marrow were also elevated in the latter group. Progesterone, however, did not influence allergen-specific IgE production, nor did it affect bronchial responses in Sal-challenged mice.

CONCLUSION

Our data show that exogenously administered progesterone aggravates the phenotype of eosinophilic airway inflammation in mice by enhancing systemic IL-5 production. Progesterone also increases bronchial hyper-reactivity.

[The effects of physical exercise on the immune system]

Physical exercise has numerous effects on the human body, including the immune system. After strenuous exercise, athletes pass through a period of impaired immune resistance. During this period, athletes are theoretically more susceptible to upper respiratory tract infections, although a causal relation has never been demonstrated. Moderate exercise seems to have a beneficial effect on the immune function, which could protect against upper respiratory tract infections. Exercise has effects on both the humoral and the cellular immune system. Doping products, except glucocorticoids, only have modest effects on the immune system, although erythropoietin may, in rare cases, cause severe side-effects. Glutamine and vitamin C could, hypothetically, prevent the negative effects of strenuous exercise on the immune function, but further studies are needed to demonstrate and explain these effects.

Oral allergy syndrome to chicory associated with birch pollen allergy

BACKGROUND

A few cases of IgE-mediated chicory allergy with oral, cutaneous, and/or respiratory symptoms are reported. We present 4 patients with inhalant birch pollen allergy and oral allergy syndrome to chicory. IgE-binding proteins in chicory and cross-reactivity with birch pollen were studied.

METHODS

Chicory extract was prepared and immunoblotting was used to study IgE reactivity and cross-reactions with birch pollen.

RESULTS

The pattern of IgE binding to chicory was variable among the patients, with protein bands recognized at 18, 21, 40, 52 and 71 kD. Bet v 1-like proteins were detected in chicory by monoclonal antibody binding. Chicory-birch pollen cross-reactivity, as studied in 2 patients from whom enough serum was available, could be demonstrated but did not involve the Bet v 1 protein family. In one of these cases, a 51-kD protein of birch pollen was found to be responsible for cross-reactivity.

CONCLUSIONS

Chicory should be added to the list of foods that can cross-react with birch pollen and cause the birch pollen-associated oral allergy syndrome.

Evaluation of the immune response to pneumococcal capsular polysaccharides

Antibody deficiency is the most common immunodeficiency. In 5% to 10% of the patients with recurrent infections that are evaluated for immunodeficiency, a specific deficiency in the immune response to capsular polysaccharides can be found. Patients with recurrent infections should therefore be tested for their capacity to produce antibodies against anti-capsular polysaccharides. As a clinical test, specific antibody levels are measured before and 14 days after immunization with the 23-valent pneumococcal polysaccharide vaccine. In this article we describe the indications, the method used to measure antibodies to capsular pneumococcal polysaccharide and the way the results have to be interpreted.

Haptoglobin directly affects T cells and suppresses T helper cell type 2 cytokine release

T helper cell type 1 (Th1) and type 2 (Th2) immune responses are characterized by a different pattern of cytokine expression following T-cell activation. Alterations of the ratio of Th1 to Th2 cells are important determinants of susceptibility to viral and parasitic infections, allergies, anti-tumour responses, and autoimmunity. In this work we bring new evidence for an effect of haptoglobin (Hp), a positive acute-phase protein, on T-lymphocyte functions. We show that Hp specifically interacts with both resting and activated CD4+ and CD8+ T cells. This specific binding results in a strong suppression of induced T-cell proliferation. In addition, Hp exhibits a strong in vitro inhibitory effect on Th2 cytokine release, while the production of interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) is only slightly inhibited at high Hp doses. As a result, the presence of Hp promotes Th1 activation over Th2 activation in vivo as evidenced in Hp-deficient mice. Anti-CD3 monoclonal antibody injection indeed resulted in predominant IL-4 production in Hp-/- mice, in contrast to predominant IFN-gamma production in Hp+/+ mice. We conclude that Hp plays a modulating role on the Th1/Th2 balance by promoting a dominant Th1 cellular response. This points to a role of acute-phase proteins in balancing immune responses.

The effect of age on cell-mediated immunity to tuberculin: a study on in vivo and in vitro tuberculin reactivity

We investigated reactivity to tuberculin in a group of 91 elderly subjects (65 years old and more) and in a control group of 53 younger subjects between 18 and 59 years old, by means of the tuberculin skin test (TST) and by an in vitro lymphocyte stimulation test (LST). The LST had been validated in preliminary tests to accurately reflect T cell reactivity towards tuberculin. We defined a LST with a stimulation index (SI) (ratio of the tuberculin stimulated cultures to the non-stimulated cultures) of 10 or more at a concentration of 0.4 microgram/ml as indicative for sensitisation to tuberculin. The correlation between TST and LST was r = 0.58 (p = 0.0001) in the elderly subjects and r = 0.64 (p = 0.0001) in the younger age group; age did not affect those correlations (p = 0.39). Of the subjects with initially negative TST, 44.4% (16 LST-positive and 16 LST-negative) reacted positive on TST as well as on LST after repeated testing. We conclude that (a) there is a statistically significant but rather weak correlation between in vivo and in vitro assays of cell-mediated immune response to tuberculin, (b) age did not influence this correlation, (c) the in vivo and in vitro tests give complementary information but cannot substitute for each other and (d) repeated TST can induce an immunological boosting phenomenon on TST as well as on LST.

Haptoglobin interacts with the human mast cell line HMC-1 and inhibits its spontaneous proliferation

Haptoglobin (Hp) is an acute phase reactant produced by hepatocytes. There is evidence for an immunomodulatory potential of Hp, though there is no clear evidence yet about the mechanisms of this action. We have previously shown that Hp interacts with the beta2-integrin CD11b/CD18. In addition, other investigators reported the binding of Hp to B lymphocytes through the CD22 receptor, and to neutrophils through two different receptors. In the present study, we investigated the interaction of haptoglobin with the human mast cell line HMC-1. We report that fluorescein isothiocyanate (FITC)-labelled haptoglobin binds to this cell line and that binding is increased by calcium in a dose- and time-dependent manner. Hp binding sites on HMC-1 were upregulated upon stimulation with phorbol myristate acetate (PMA)/A23187 and after treatment with anti-CD43 and anti-CD44 monoclonal antibodies (MoAbs). HMC-1 cells do not express either CD11b/CD18 or CD22 receptors, indicating that the haptoglobin-binding receptor on this cell line is different from the known receptors. Assessment of cell function showed that Hp inhibits the spontaneous growth of HMC-1 up till 40% at higher Hp concentrations, but it did not exhibit any effect on the expression of CD54 on the release of either tryptase or IL-1ra. In conclusion, haptoglobin binds specifically to human mast cells via a receptor different from CD11b/CD18 and CD22, and may play a role in the modulation of mast cell functions. Exploration of Hp effects in mast cell-dependent diseases such as allergic rhinitis and urticaria seems warranted.

Different circulating lymphocyte profiles in patients with different subtypes of juvenile idiopathic arthritis

OBJECTIVE

To determine the immunophenotypic profiles of circulating lymphocytes in patients with different disease types of Juvenile Idiopathic Arthritis (JIA).

METHODS

Peripheral blood lymphocyte subsets from 19 patients with oligoarticular JIA (o-JIA), 10 patients with polyarticular JIA (p-JIA), 12 patients with systemic JIA (s-JlA) andfrom 41 age-matched healthy controls were characterized by two color immunofluorescence flow cytometry analysis.

RESULTS

Patients with o-JIA and p-JIA had increased numbers of HLA-DR+ Tcells and Tcells co-expressing CD57 and CD16/56, indicating T cell activation and terminal differentiation of CD8+ T cells respectively. By contrast, in patients with s-JIA there was no increase in the activation or differentiation markers on T cells, but a profound decrease in circulating NK cells. All patients had hypergammaglobulinemia consistent with B cell hyperactivity, but increased numbers of CD5+ B cells were found only in o-JIA and p-JIA.

CONCLUSION

Distinct immunophenotypic lymphocyte profiles in patients with o-JIA and p-JIA compared to patients with s-JIA as demonstrated in this study, are consistent with afundamental heterogeneity of the disease.

Effects of anti-tumour necrosis factor, interleukin-10 and antibiotic therapy in the indometacin-induced bowel inflammation rat model

BACKGROUND

The administration of indometacin to rats increases intestinal permeability and induces inflammatory pathology of the small bowel. This represents a potential model for Crohn's disease.

AIMS

To analyse the pathogenic role of T cells, tumour necrosis factor and bacterial flora in indometacin-induced changes in small bowel permeability and inflammation.

METHODS

Rats were given indometacin, 13 mg/kg, on day 1 and day 2. The effects of antibiotic (metronidazole, aztreonam and amoxicillin/clavulanic acid), anti- tumour necrosis factor and interleukin-10 therapy were evaluated. The parameters used were weight change, serum haemoglobin, chromium-51 ethylenediaminetetra-acetate permeability and macro-and microscopic score on day 5. Results in conventionally harboured rats were compared with those in T-cell-free rats. Additional in vitro experiments were carried out to test the effect of metronidazole on tumour necrosis factor production.

RESULTS

Indometacin administration resulted in small bowel ulcers and inflammation, independently of T cells. Metronidazole was more potent than amoxicillin/clavulanic acid and anti-tumour necrosis factor in improving the indometacin-induced small bowel inflammation. Only part of the efficacy was through improvement of increased intestinal permeability. Aztreonam and interleukin-10 had no effect. Metronidazole also suppressed in vitro lipopolysaccharide-induced tumour necrosis factor production, suggesting a therapeutic effect of this drug through the inhibition of tumour necrosis factor.

CONCLUSIONS

These data implicate anaerobic bacteria and tumour necrosis factor production, but not T cells, as essential elements of the pathogenesis of indometacin-induced small bowel inflammation. Tumour necrosis factor is also involved in the change in intestinal permeability. Metronidazole was the most efficacious drug in this model, probably because it suppressed anaerobic bacteria and directly inhibited tumour necrosis factor production.

B7 interactions with CD28 and CTLA-4 control tolerance or induction of mucosal inflammation in chronic experimental colitis

CD28-B7 interaction plays a critical costimulatory role in inducing T cell activation, while CTLA-4-B7 interaction provides a negative signal that is essential in immune homeostasis. Transfer of CD45RB(high)CD4(+) T cells from syngeneic mice induces transmural colon inflammation in SCID recipients. This adoptive transfer model was used to investigate the contribution of B7-CD28/CTLA-4 interactions to the control of intestinal inflammation. CD45RB(high)CD4(+) cells from CD28(-/-) mice failed to induce mucosal inflammation in SCID recipients. Administration of anti-B7.1 (but not anti-B7.2) after transfer of wild-type CD45RB(high)CD4(+) cells also prevented wasting disease with colitis, abrogated leukocyte infiltration, and reduced production of proinflammatory cytokines IL-2 and IFN-gamma by lamina propria CD4(+) cells. In contrast, anti-CTLA-4 treatment led to deterioration of disease, to more severe inflammation, and to enhanced production of proinflammatory cytokines. Of note, CD25(+)CD4(+) cells from CD28(-/-) mice similar to those from the wild-type mice were efficient to prevent intestinal mucosal inflammation induced by the wild-type CD45RB(high) cells. The inhibitory functions of these regulatory T cells were effectively blocked by anti-CTLA-4. These data show that the B7-CD28 costimulatory pathway is required for induction of effector T cells and for intestinal mucosal inflammation, while the regulatory T cells function in a CD28-independent way. CTLA-4 signaling plays a key role in maintaining mucosal lymphocyte tolerance, most likely by activating the regulatory T cells.