Late allergic airway response to segmental bronchopulmonary provocation in allergic subjects is related to peripheral blood basophil histamine release

Histamine release and inflammatory cell infiltration in airway Mucosa in methylene diphenyl diisocyanate (MDI)-induced occupational asthma

INTRODUCTION

Although methylene diphenyl diisocyanate (MDI) is widely used in industries, there have been few studies of the pathogenic mechanisms of MDI-induced occupational asthma (MDI-OA).

METHODS

We performed immunohistochemical analyses, measured inflammatory mediators and cytokines, and quantified histamine release (HR) from peripheral basophils in MDI-OA patients. Thirteen MDI-exposed workers (five MDI-OA, two MDI-induced esoinophilic bronchitis, and six asymptomatic exposed controls, AEC) were enrolled.

RESULTS AND DISCUSSION

Immunochemical analyses indicated significantly increased anti-eosinophilic cationic protein-stained cells in MDI-OA patients as compared with controls (P < 0.05). Sputum eosinophil cationic protein levels were increased after MDI-specific inhalation challenge test in MDI-OA/EB patients (P < 0.02). Sputum eosinophil counts were highly correlated with IL-8 and MMP-9 levels (P < 0.05 and P < 0.01, respectively). Basophil HR was significantly increased in MDI-OA patients after stimulations with anti-IgG4 and MDI-human serum albumin conjugates (both P < 0.05). Eosinophil activation is a major feature of airway inflammation in MDI-OA patients. Increased HR by MDI may contribute to the pathogenic mechanisms of MDI-OA.

L3L4ES antigen and secretagogues induce histamine release from porcine peripheral blood basophils after Ascaris suum infection

The aim of this paper was to investigate the role of porcine basophils in protective immunity. Experimental pigs were infected with 10(3) Ascaris suum eggs daily for 21 days. Control pigs were maintained helminth-free. Circulating porcine basophils were isolated from the anticoagulated whole blood of A. suum-infected and noninfected pigs by dextran (4.5%) sedimentation of erythrocytes or by the centrifugation of dextran-isolated leukocytes through discontinuous Percoll gradients. Results showed that 2.2% of the isolated leukocytes, stained with May-Grunwald Giemsa, were basophils. Each basophil from infected pigs contained 1.30 x 10(-2) to 1.20 x 10(-1) pg of histamine. Peripheral blood basophils (PBBs) from infected swine released 49% specific histamine when induced with A. suum-derived antigen (L3L4ES), 55% with anti-immunoglobulin G, and 62% with calcium ionophore A23l87. During A. suum infection, the number of isolated basophils and histamine levels peaked at 14 to 21 days postinfection and then showed a significant decrease. Percent-specific histamine released from PBBs by infected swine was significantly greater than that released by control pigs. The L3L4ES antigen and secretagogues effectively induced specific/nonspecific histamine release from PBBs and should facilitate future investigations of porcine basophils.

Pathogenesis of asthma

There is now strong evidence that airway inflammation is a predominant underlying problem in patients with asthma, and it has been suggested that ongoing inflammation may lead to airway injury and remodeling. There is also recent evidence that longstanding asthma could be associated with loss of elastic recoil, which can enhance airway obstruction and worsen asthma control [82,83]. Therefore, the use of anti-inflammatory therapy has been advocated in all guidelines, including the National Asthma Education and Prevention Program (NAEPP) Expert Panel Report [84] and its recent update [85] that recommended inhaled steroids as a first mode of therapy for patients with mild, moderate, or severe, persistent asthma. There is preliminary evidence that early institution of anti-inflammatory therapy might lead to disease modification and limit the progression of subepithelial fibrosis and airway remodeling. The pathogenesis of asthma clearly involves many cells and mediators, although the contribution of each individual factor is probably different from patient to patient depending on the setting and stimulus. Although currently available therapies are highly effective in controlling asthma symptoms and limiting exacerbations in the majority of patients, there is still a subset of patients that proceed to develop severe asthma with decreased lung function, lack of responsiveness to therapy, or frequent exacerbations. It is hoped that rapid progress in the area of asthma genetics and pharmacogenetics will yield a more precise and patient-specific understanding of asthma pathogenesis and allow practitioners to prescribe therapies that are designed for a particular patient or exacerbation. That will undoubtedly help to improve the care of asthma, limit its morbidity, and reduce the side effect of medications.

Influence of bronchial allergen challenge on histamine release by human basophils

BACKGROUND

Basophils can be primed by cytokines such as interleukin (IL) -3, IL-5 or granulocyte macrophage-colony stimulating factor (GM-CSF). It has been described that the concentrations of these cytokines are enhanced at sites of allergic inflammation as well as systemic in allergic asthma.

OBJECTIVE

To investigate the priming status of basophils as detected by thapsigargin-induced histamine release during bronchial allergen challenge.

METHODS

Ten subjects allergic to house dust mite were challenged via an aerosol delivery system. Spontaneous leucocyte histamine release as well as histamine release induced by various stimuli was measured in vitro at several time points. In addition, lung function parameters, serum IL-5 and blood eosinophil counts were evaluated.

RESULTS

We found no effect of bronchial allergen challenge upon spontaneous leucocyte histamine release, nor upon histamine release induced by anti-immunoglobulin (Ig) E, house dust mite extract, C5a, fMLP, IL-3, PMA+ thapsigargin or IL-3+ thapsigargin. However, the priming status of basophils as measured by thapsigargin-induced histamine release was enhanced at 24 h after bronchial allergen challenge. Analysis of the individual data showed a heterogeneous initial response (30 min, 6 h) followed by a predominant increase at 24 h after allergen challenge. This increase in the thapsigargin-induced histamine release correlated with the increase in serum IL-5 levels at 24 h after allergen challenge.

CONCLUSION

The priming status of human basophils as measured by thapsigargin-induced histamine release is enhanced 24 h after allergen challenge.

Increased numbers of both airway basophils and mast cells in sputum after allergen inhalation challenge of atopic asthmatics

Mast cells and basophils are metachromatic cells that participate in allergic inflammation. Allergen challenge to the airways of atopic asthmatic individuals increases levels of metachromatic cells, which may reflect an increase in mast cells, basophils, or both. We conducted a study to characterize the kinetics of basophil and mast cell recruitment to the airways of atopic asthmatic subjects after allergen inhalation challenge, using monoclonal antibodies specific for each type of cell. Of 19 subjects, 14 developed both early- and late-phase asthmatic responses (dual responders [DRs]), whereas five developed only early asthmatic responses (early responders [ERs]) after allergen inhalation. There was a significant increase in the number of sputum eosinophils (p < 0.002) and basophils (p < 0.002) at 7 h and 24 h after challenge in both ERs and DRs. There was also a significant increase in the number of activated eosinophils (p = 0. 00002) and mast cells (p = 0.009) in sputum at 7 h and 24 h after challenge in DRs, but not in ERs (p > 0.4). DRs had a significantly higher number of allergen-induced sputum basophils than did ERs (p < 0.01), and sputum basophils correlated significantly with airway hyperresponsiveness (AHR) to methacholine at 24 h after challenge (r = 0.66, p = 0.002). DRs tended to have higher allergen-induced basophil levels than did ERs, which may contribute to the observed AHR.