High-dose bee venom exposure induces similar tolerogenic B-cell responses in allergic patients and healthy beekeepers.

BACKGROUND: The involvement of B cells in allergen tolerance induction remains largely unexplored. This study investigates the role of B cells in this process, by comparing B-cell responses in allergic patients before and during allergen immunotherapy (AIT) and naturally exposed healthy beekeepers before and during the beekeeping season. METHODS: Circulating B cells were characterized by flow cytometry. Phospholipase A2 (PLA)-specific B cells were identified using dual-color staining with fluorescently labeled PLA. Expression of regulatory B-cell-associated surface markers, interleukin-10, chemokine receptors, and immunoglobulin heavy-chain isotypes, was measured. Specific and total IgG1, IgG4, IgA, and IgE from plasma as well as culture supernatants of PLA-specific cells were measured by ELISA. RESULTS: Strikingly, similar responses were observed in allergic patients and beekeepers after venom exposure. Both groups showed increased frequencies of plasmablasts, PLA-specific memory B cells, and IL-10-secreting CD73- CD25+ CD71+ BR 1 cells. Phospholipase A2-specific IgG4-switched memory B cells expanded after bee venom exposure. Interestingly, PLA-specific B cells showed increased CCR5 expression after high-dose allergen exposure while CXCR4, CXCR5, CCR6, and CCR7 expression remained unaffected. CONCLUSIONS: This study provides the first detailed characterization of allergen-specific B cells before and after bee venom tolerance induction. The observed B-cell responses in both venom immunotherapy-treated patients and naturally exposed beekeepers suggest a similar functional immunoregulatory role for B cells in allergen tolerance in both groups. These findings can be investigated in other AIT models to determine their potential as biomarkers of early and successful AIT responses.

Asthma is associated with reduced fibrinolytic activity, abnormal clot architecture, and decreased clot retraction rate.

The aim of this study was to assess whether steroid-naïve asthma modulates hemostasis. We evaluated the clot retraction rate (CRR), fibrinolysis rate (FR), clot density (CD) (by confocal microscopy), plasma levels of plasminogen activator inhibitor (PAI-1), and factor XIII (FXIII), NO in exhaled breath (FENO ), spirometry (FEV1 ) and eosinophil count (EOS) in 36 patients with allergic, steroid-naïve asthma and in 34 healthy controls. We observed significantly (P < 0.001) reduced CRR, FR, and FEV1 and increased FENO , EOS, PAI-1, FXIII, and CD in patients with asthma compared with controls. In patients with asthma, FR negatively correlated with CD, FXIII, PAI-1, FENO , and EOS and positively with FEV1 . FXIII positively correlated with CD. Clot retraction rate negatively correlated with FENO and positively with FEV1 (all P < 0.001). These novel findings suggest that asthma itself is associated with decreased CRR and reduced fibrinolytic potential resulting from alterations in clot architecture and elevated levels of plasma FXIII and PAI-1.

Airway inflammation and eotaxin in exhaled breath condensate of patients with severe persistent allergic asthma during omalizumab therapy.

PURPOSE: The central role of IgE in allergic inflammation in asthma has provided a rationale for the development of omalizumab, the humanized monoclonal anti-IgE antibody. The aim of the study was to determine the effect of omalizumab treatment on changes in airway inflammatory process and eotaxin in exhaled breath condensate in patients with persistent severe allergic asthma. MATERIAL AND METHODS: The study was performed on a group of 19 patients with severe persistent allergic asthma treated with conventional therapy (according to GINA 2006) and with or without omalizumab (9 vs 10 patients). Eotaxin in exhaled breath condensate, exhaled nitric oxide, blood eosinophil count and serum ECP were measured before and after 16 weeks of therapy. RESULTS: In the group treated with omalizumab, a statistically significant decrease in the concentrations of eotaxin in EBC, FENO, serum ECP, and blood eosinophil count after 16 weeks of treatment was observed. Statistically significant correlations were revealed between the decrease in eotaxin and the decrease in FENO, serum ECP and blood eosinophil count after omalizumab therapy. CONCLUSIONS: Downregulation of eotaxin expression in the airways through limitation of eosinophilic inflammation could be essential in the beneficial effect of anti-IgE therapy with omalizumab in asthma patients.

Eotaxin in exhaled breath condensate of allergic asthma patients with exercise-induced bronchoconstriction.

BACKGROUND: Eosinophils are the key inflammatory cells in asthma, and more and more evidence suggests their crucial role in exercise-induced bronchoconstriction (EIB). Eotaxin, as the most important chemotactic factor for eosinophils, plays an important role in the pathogenesis of asthma. OBJECTIVES: The aim of the study was to evaluate the changes in eotaxin levels in exhaled breath condensate (EBC) following intensive exercise in allergic asthmatics. METHODS: The study was performed in a group of 27 asthmatics (17 with EIB, 13 without EIB) and 9 healthy volunteers. Changes induced by intensive exercise in the concentrations of eotaxin in EBC during the 24 h after an exercise test were assessed. The possible correlations of these measurements with the results of other tests commonly associated with eosinophilic airway inflammation were also determined. RESULTS: In asthmatic patients with EIB, a statistically significant increase in eotaxin concentrations in EBC collected during the first 24 h after an exercise test - with maximal increase after 6 h - was revealed. A statistically significant correlation between the maximum increase in eotaxin concentrations in EBC after exercise, and an increase in either serum eosinophil cationic protein or F(ENO) 24 h after exercise in the group of asthmatics with EIB, was observed. CONCLUSIONS: Our results confirm connections between EIB and airway eosinophilic inflammation. The increase of eotaxin in asthmatic airways, by promoting the migration and activation of eosinophils, may play an important role in upregulation and sustaining of the airway inflammation observed in EIB in asthmatic patients.

Bronchial hyperresponsiveness and airway inflammation in patients with seasonal allergic rhinitis.

BACKGROUND: Allergic rhinitis is a chronic inflammatory disease induced by an immunoglobulin (Ig) E-mediated reaction after exposure to an allergen. Many patients with allergic rhinitis and no clinical evidence of asthma show a heightened response to histamine. OBJECTIVES: The aims of the study were to measure changes in markers of airway inflammation in patients with seasonal allergic rhinitis and estimate changes in bronchial reactivity before and during the pollen season. METHODS: The study sample comprised 22 patients sensitized to grass pollen and 10 healthy volunteers. Based on the results of the bronchial provocation test (BPT) during the pollen season, we divided patients into those with and without bronchial hyperresponsiveness (BHR). We determined changes in nitrite and pH in exhaled breath concentrate (EBC), fraction of exhaled nitric oxide (FE(NO)), blood eosinophil count, and BPT results before and during the pollen season. RESULTS: In allergic rhinitis patients with BHR, we observed an increase in EBC nitrite (5.44 [2.33] vs 8.57 [3.35] nmol/mL, P = .02) and FE(NO) (20.90 [13.68] vs. 43.40 [31.60] ppb, P = .02) and a decrease in EBC pH (7.07 [0.33] vs. 6.74 [0.28], P = .01) during the pollen season. In allergic rhinitis patients with BHR, the increase in BHR was negatively correlated with increased FE(NO) and EBC nitrite and positively correlated with a decrease in EBC pH during the pollen season. CONCLUSIONS: Our results revealed a relationship between increased BHR in patients with seasonal allergic rhinitis and changes in airway inflammation markers. EBC pH, EBC nitrite concentration, and FE(NO) could act as prognostic markers for identifying patients at risk of developing asthma.

RANTES in exhaled breath condensate of allergic asthma patients with exercise-induced bronchoconstriction.

BACKGROUND: The response of asthmatics to exercise differs from that of healthy subjects, and the mechanisms responsible for exercise-induced bronchoconstriction (EIB) remain to be elucidated. OBJECTIVES: The aim of this study was to evaluate changes in RANTES levels in exhaled breath condensate (EBC) following intensive exercise in allergic asthmatics. METHODS: The study was conducted in a group of 19 asthmatics (11 with EIB and 8 without EIB) and 7 healthy volunteers. Changes in the concentrations of RANTES in EBC induced during the 24 h after intensive exercise were determined. Moreover, these measurements were tested for possible correlations with the results of other tests commonly associated with asthma as well as with changes in airway inflammation after exercise. RESULTS: In contrast to asthmatic patients without EIB and healthy controls, in asthmatics with EIB RANTES concentrations were statistically significantly increased in EBC collected during the first 24 h after an exercise test. There was a statistically significant correlation between the maximum increase in RANTES concentrations in EBC after exercise and either baseline exhaled nitric oxide (F(ENO)) or bronchial hyperreactivity to histamine and an increase in serum eosinophil cationic protein or F(ENO) 24 h after exercise in the EIB asthmatics. CONCLUSIONS: The increase in RANTES in asthmatic airways, promoting the migration and activation of inflammatory cells including eosinophils, may play an important role in the upregulation of airway inflammation after EIB in asthmatic patients.