Giampaola Pesce

Minimal persistent inflammation is present at mucosal level in patients with asymptomatic rhinitis and mite allergy

The natural exposure to house dust mites causes sensitization in genetically susceptible patients. Persistent exposure of sensitized patients causes chronic inflammation, and consequently, hyperreactivity, thus promoting the development of clinical features. Recently, intercellular adhesion molecule-1 (ICAM-1)/CD54 expression on epithelial cells triggered by allergen has been demonstrated and related to the inflammation caused by the allergic reaction. Therefore we evaluated the possible presence of inflammation (i.e., inflammatory cell infiltrate and ICAM-1/CD54 expression on epithelium) at conjunctival and nasal levels in patients with asymptomatic allergic rhinitis caused by mites, in their relatives living in the same environment, and in healthy volunteers. In addition, the possible relationship between inflammation and house dust mite allergen exposure was evaluated. Conjunctival and nasal scrapings of allergic subjects enrolled in the study showed many inflammatory cells. A mild ICAM-1/CD54 expression on conjunctival and nasal epithelium was detectable in allergic subjects, whereas relatives and healthy volunteers showed few inflammatory cells and no ICAM-1/CD54 expression on epithelial cells. A detectable level of house dust mite, sufficient to cause sensitization, was found in all houses. This study demonstrates a minimal persistent inflammation at conjunctival and nasal levels constantly detectable in patients without symptoms who are sensitized to mites and continuously exposed to the natural allergens.

Cetirizine reduces inflammatory cell recruitment and ICAM-1 (or CD54) expression on conjunctival epithelium in both early- and late-phase reactions after allergen-specific challenge ☆ ☆☆ ★ ★★

BACKGROUND Allergen-specific conjunctival challenge (ASCC) is a safe and reproducible experimental model of allergic conjunctivitis and a useful tool in the evaluation of effectiveness and possible mechanisms of action of drugs commonly used in the treatment of allergic diseases. OBJECTIVE The protective effect of cetirizine on inflammatory changes after ASCC was assessed in 12 patients with rhinoconjunctivitis caused by Parietaria judaica in a double-blind study. METHODS After a screening ASCC was performed, patients were randomized into two treatment groups; each patient was given cetirizine (oral tablets) 10 mg twice daily, or matching placebo for 3 1/2 days in off-pollen season. Clinical evaluation (itching, hyperemia, lacrimation, and swelling of eyelids) and cytologic assessment (number of inflammatory cells in conjunctival scraping and evaluation of intercellular adhesion molecule-1 (ICAM-1)/CD54 expression on epithelial cells) were performed at baseline, 30 minutes (i.e., early-phase reaction [EPR]), 6 hours, and 24 hours (i.e., late-phase reaction [LPR]) after ASCC, before and after treatment. RESULTS The EPR clinical events and the EPR total number of inflammatory cells were significantly reduced by cetirizine compared with placebo. The LPR clinical events and inflammatory cell recruitment were reduced by cetirizine in a similar manner. Both eosinophil and neutrophil numbers were decreased by active drug in EPR and LPR. Furthermore, ICAM-1/CD54 expression was significantly reduced by cetirizine in both the EPR and LPR compared with placebo. CONCLUSIONS This study shows that cetirizine has a protective effect on clinical and cellular EPR and LPR events (including ICAM-1/CD54 expression on epithelium) induced by ASCC.

Allergic subjects express intercellular adhesion molecule — 1 (ICAMA or CD54) on epithelial cells of conjunctiva after allergen challenge

BACKGROUND Allergic inflammation can be experimentally reproduced in vivo in humans, by means of the conjunctival provocation test with allergen. The allergen stimulation triggers an early clinical response and an almost simultaneous cellular infiltrate. Among the factors that can contribute to the local cellular recruitment, we postulate a possible early involvement of CD54 in the development of inflammation caused by the allergic reaction. METHODS We used a sensitive immunocytochemical immunoenzymatic alkaline phosphatase-monoclonal antialkaline phosphatase technique to detect the possible expression of CD54 molecule on epithelial cells of conjunctiva in 15 allergic subjects and in 15 healthy individuals in basal conditions and after allergen challenge (Parietaria judaica) during the off-pollen season. RESULTS At baseline all studied individuals did not evidence CD54 expression on epithelial cells; 30 minutes after allergen challenge, all the allergic individuals showed a marked expression of CD54 on conjunctival epithelium, whereas none of healthy subjects showed any CD54 expression. First, CD54 expression on conjunctival epithelium after specific provocation test appeared as a specific phenomenon occurring only in sensitized subjects; moreover, it is an immediate event concomitant with the local inflammatory infiltrate. Therefore conjunctival epithelium unexpectedly appeared to be more than a bystander in the allergic reaction; it may be perceived as an active participant interacting with the inflammatory infiltrate. CONCLUSIONS These findings indicate that CD54 may play a central role in the allergic inflammation and strongly support the concept that maneuvers designed to interact with the adhesion machinery expressed on inflammatory cells and epithelium may be a helpful therapeutic approach.

ICAM-1 on epithelial cells in allergic subjects: a hallmark of allergic inflammation.

Allergen-specific challenge was first shown to induce ICAM-1 expression on epithelial cells (ECs) of conjunctiva in allergic patients. The data have also been confirmed in the nose. We then checked for the presence of ICAM-1 consequent to natural exposure to allergens. For both conjunctivitis and rhinitis due to pollen we confirmed, during the pollen season, the presence of ICAM-1 on ECs. We demonstrated the endogenous source of ICAM-1 by in situ hybridization both in vitro and in vivo. ICAM-1 could be an activation marker on ECs, or could, enhanced EC susceptibility to bind offending cells such as eosinophils (LFA-1+). ICAM-1 is also a receptor for the vast majority of rhinoviruses, which are known to provoke, mainly in children, asthma attacks. Since we found that mite allergens can induce ICAM-1 on ECs, even during clinical latency, allergy may be considered as a primary event leading to asthma (through rhinovirus infection) and non-specific hyperreactivity.

Adhesion molecules of allergic inflammation: recent insights into their functional roles

Canonica GW, Ciprandi G, Buscaglia S, Pesce G, Bagnasco M. Adhesion molecules of allergic inflammation: recent insights into their functional roles.

Azelastine eye drops reduce and prevent allergic conjunctival reaction and exert anti‐allergic activity

Background Azelastine is a selective H1‐receptor antagonist, which has previously been demonstrated to be effective in the treatment of allergic rhinitis. We have recently demonstrated that nasal azelastine inhibits the clinical and intlammatory events following nasal allergen challenge. Particularly, we focused our attention on ICAM‐1 expression on epithelial cells, since it is the natural ligand of LFA‐1, an adhesion molecule expressed by leucocytes, including eosinophils.

Pharmacokinetics of Der p 2 Allergen and Derived Monomeric Allergoid in Allergic Volunteers

Background: Presently, sublingual immunotherapy is widely used as an alternative to the injection route for respiratory allergy, but its pharmacokinetics in humans is poorly known, and data are available only for Par j 1 allergen. We aimed at assessing the biodistribution of iodine-123-radiolabelled Der p 2 in allergic volunteers. Methods: Purified Der p 2 and its monomeric allergoid were radiolabelled with iodine-123 and administered sublingually to 7 allergic volunteers. The subjects were allowed to swallow 6 min after administration. Dynamic (up to 10 min) and static scintigraphic images (30 min, 1, 2, 3 and 20 h) were recorded, and blood samples were obtained at different time points to measure the plasma radioactivity and to assess the presence of circulating radiolabelled species by gel chromatography. Results: The local pharmacokinetics did not differ between allergen and allergoid. Plasma radioactivity began to increase only after swallowing and peaked at 1–2 h. Both the allergen and the allergoid persisted in the mouth for several hours, and traces could be detectable up to 20 h. At radioactivity plasma peak, gel chromatography showed that a fraction of the allergoid, but not the allergen, was absorbed as an intact molecule. Conclusions: These results indicate that the pharmacokinetics of sublingual administration is independent of the allergen used and characterized by the long persistence in the mouth. The contribution of enteric absorption of the allergoid in the mechanism of action of sublingual immunotherapy remains to be defined.

Intercellular adhesion molecule-1 on cultured human epithelial cell lines: influence of proinflammatory cytokines

Paolieri F, Battifora M, Riccio AM, Pesce G, Canonica GW, Bagnasco M. Intercellular adhesion molecule‐1 on cultured human epithelial cell lines: influence of proinflammatory cytokines.

Diagnostic Accuracy of IgA Anti‐Tissue Transglutaminase Antibody Assays in Celiac Disease Patients with Selective IgA Deficiency

Abstract:  Clinical studies have estimated a 10‐ to 20‐fold increased risk for celiac disease (CD) in patients with selective IgA deficiency (SIgAD). For this reason, screening for CD is mandatory in SIgAD patients, but it represents a special challenge since the specific IgA class antibodies against gliadin (AGA), endomysium (EMA), and tissue‐transglutaminase (tTG) are not produced in patients with CD. IgG class counterparts of these antibodies may be informative; in particular IgG EMA has been demonstrated to be a valid marker for diagnosing CD in SIgAD cases, but it is not used much in clinical laboratories, because it is cumbersome and involves some technical difficulties. Even if it was widely used in clinical laboratories, the measuring of IgG AGA has shown a less‐than‐optimum diagnostic accuracy, so that now it tends to be substituted by tests for anti‐tTG IgG, for which the few available studies have shown diagnostic performances superior to AGA. Since it is not known whether various available methods for measuring IgG anti‐tTG antibodies offer similar diagnostic performances, we have compared the results obtained from nine second‐generation commercial methods (D‐tek, Phadia, Immco, Orgentec, Radim, Euroimmun, Inova, Aesku, Generic Assays), measuring IgG anti‐tTG antibodies in 20 patients with CD and SIgAD and in 113 controls (9 patients with SIgAD without CD, 54 patients with chronic liver disease, and 50 healthy individuals). Diagnostic sensitivity, calculated by means of ROC plot analysis, ranged between 75% and 95%, and specificity ranged from 94% to 100%. In the same population, the diagnostic sensitivity and specificity of AGA IgG were 40% and 87%, respectively. Even though they perform differently, all IgG anti‐tTG methods evaluated are reliable serological assays for the diagnosis of CD in SIgAD patients, with diagnostic accuracy superior to the AGA IgG method. The methods that use a mix of tTG and gliadin peptides as the antigenic preparation have a specificity slightly lower than that of the methods that use only tTG.

Comparison of ELISA for tissue transglutaminase autoantibodies with antiendomysium antibodies in pediatric and adult patients with celiac disease.

Background: Tissue transglutaminase (t‐TG) is the main autoantigen recognized by the endomysium antibodies (EMA) observed in patients with celiac disease (CD). The aim of the study was to assess an ELISA method for t‐TG antibodies (t‐TGA) with respect to EMA IF assay in pediatric and adult patients.