Electron microscope study of basophilic cells in allergic nasal secretions

Allergic and Nonallergic Rhinitis: Classification and Pathogenesis Part I. Allergic Rhinitis

Chronic rhinitis, although not life-threatening, substantially interferes with one's quality of life. Associated symptoms of nasal obstruction, sneezing, rhinorrhea, and anosmia afflict an estimated 40 million Americans. Directed clinical history and physical examination combined with noninvasive and routine procedures permit physicians to diagnose the myriad conditions causing rhinitis. Although the precise etiology of many of these conditions is only partially known, a practical diagnostic classification can be formulated based on clinical and laboratory findings. An understanding of the pathophysiology of allergic rhinitis as well as the other less understood entities provides the clinician with a integral foundation to implement preventative and therapeutic measures. This comprehensive review should provide the reader an opportunity to better understand and appreciate the causes and pathophysiology of chronic rhinitis. Part I of this article concentrates on IgE-mediated reactions, mediators, and drugs involved in allergic rhinitis. Part II focuses on the recent advances gained in understanding the nonallergic (non-IgE) causes of chronic rhinitis.

Nasal Cytology in Clinical Practice

Analysis of the nasal cytology provides information regarding the pathophysiology and response to therapy of the airway. This paper reviews the techniques for obtaining and interpreting specimens. The discussion focuses on the epithelial and inflammatory cells and the patterns seen in allergic, infectious and structural nasal disorders.

Mode of action of intranasal corticosteroids

The mode of action of intranasal corticosteroids (INCS) is complex. It is not known whether INCS penetrate the nasal mucosa or act on target cells; however, their low systemic activity supports the concept of local action on nasal mucosa. This local effect can nonetheless influence a variety of inflammatory cells and their mediators such as epithelial cells, lymphocytes, basophils, mast cells, and Langerhans cells. Corticosteroid-induced inhibition of immunoglobulin E-dependent release of histamine is a possible but unproven mode of action. Epithelial cells are an important target for corticosteroids, and INCS concentration is high at the epithelial surface. INCS may combine with the corticosteroid receptors in epithelial cells, which are then expelled into the airway lumen together with the dead epithelial cells or migrating inflammatory cells. A reduced influx of mediator cells may explain some of the effects of INCS on rhinitis symptoms, but it cannot explain all of the effects because INCS also reduce the early-phase sneezing and rhinorrhea after an allergen challenge outside the pollen season. In this situation, the number of surface mast cells/basophils is very low, as it is in the absence of allergic rhinitis. The mechanism by which INCS treatment of allergic rhinitis reduces itching, sneezing, and rhinorrhea, the characteristic symptoms of an early-phase response involving mast cell release of histamine, remains to be determined. Studies should be conducted to characterize the broad range of mechanisms by which INCS produce their therapeutic effects in allergic rhinitis.

Quantification of histamine in plasma and pulmonary fluids from horses with chronic obstructive pulmonary disease, before and after 'natural (hay and straw) challenges'

A commercial radioimmunoassay kit was used to quantify histamine concentrations of plasma, bronchoalveolar lavage fluid (BALF) and pulmonary epithelial lining fluid (PELF) of normal horses and horses with chronic obstructive pulmonary disease (COPD), before and after 'natural (hay and straw) challenge' (NC). There were no significant changes in the concentrations of histamine in plasma or BALF at 0.5 or 5 h after NC, but the PELF histamine concentration of COPD affected horses was significantly increased at 5 h, but not at 0.5 h, following NC. As the histamine concentrations of whole BALF lysates were significantly correlated with the numbers of metachromatically staining cells, presumed to be mast cells and/or basophils, these findings support involvement of a late phase, IgE mediated, hypersensitivity reaction in the pathogenesis of equine COPD.

Tryptase levels in nasal-lavage fluid as an indicator of the immediate allergic response

To examine mast cell involvement in allergic rhinitis, levels of tryptase, a specific marker for mast cell activation, and histamine, a marker of mast cell and basophil activation, were measured in nasal-lavage fluid after nasal-allergen challenge. Twelve atopic subjects with allergic rhinitis and five nonatopic subjects were challenged with timothy grass or ragweed pollen at increasing doses of allergen. Tryptase and histamine levels were determined by an ELISA and radioenzyme assay, respectively; clinical responses were measured by assessment of sneezing, rhinorrhea, nasal congestion, and ocular tearing or itching. A positive clinical response was observed in seven of the atopic subjects and in none of the nonatopic subjects. Tryptase levels increased at least sevenfold higher than baseline levels in 100% of the atopic clinical responders and reached a maximum at the same dose of allergen where clinical symptoms were maximal. In contrast, histamine levels were only threefold or greater elevated in five of seven atopic clinical responders at this dose of allergen. (Histamine levels were lower in one subject and were only 50% higher in another subject than the corresponding baseline value.) Histamine levels and symptom scores were maximal at the same dose of allergen in only four of seven clinical responders. Overlap of peak mediator levels in subjects without a clinical response with those of the clinical responders occurred only in the case of histamine. Tryptase levels in nasal-lavage fluid appear promising as a useful indicator of allergic reactions and indicate that mast cell activation is the major factor in the immediate nasal-allergic response.

Dynamics of mast cell degranulation in human allergic nasal epithelium after provocation with allergen

The histamine content in the nasal epithelial layer of twenty-five patients with nasal allergy was measured before, 10 min after and 1 hr after nasal provocation with allergen. A decrease in histamine content was observed 10 min after provocation compared to the values obtained before provocation (P less than 0.05). There was a tendency for an increase in the histamine content of the nasal epithelium one hour after provocation when compared with the amounts present 10 min after provocation (P less than 0.1). Mast cells in the nasal epithelial layer of a further five patients were studied by electron microscopy 10 min and 1 hr after provocation. The rate of mast cell degranulation appeared to decrease 1 hr after provocation when compared with 10 min. Our study suggests that some mast cells commence their migration to the nasal epithelial layer over a short time period and that they may play a role in the onset of the allergic nasal reaction in patients with allergic nasal symptoms.

Basophils in human disease

Hypersensitivity reactions containing significant infiltrates of basophils occur in a large proportion of allergic diseases such as contact dermatitis, atopic dermatitis, and allergic rhinitis, and are quite deleterious. However, the potential usefulness of such responses can be recognized in similar reactions in guinea pigs responding to tissue invasion by complex multicellular parasites in which interactions occur between thymic-derived T lymphocytes, antibodies, and basophils in immune resistance responses. Perhaps inappropriate and deleterious allergic responses to pollens, chemicals, and insects is the price that we must pay for the ability to reject complex parasites.

Mast cells in allergic nasal epithelium and lamina propria before and after provocation. An electron microscopic study

A study of mast cells in subjects with nasal allergy was made by electron microscopy before and after provocation in three areas; the nasal epithelium, the subepithelial layer and the deep layer of the nasal lamina propria. The ration of degranulation of the mast cells in the nasal epithelium and subepithelial layer increased after provocation. The main features of exchanged granules of the mast cells in these areas were (1) swelling of lower electron density of the area enclosed by perigranular membrane, (2) lower electron density of the total area of granular substance with fibrillar and reticular changes, and (3) the disappearance of granular substance. It was, therefore, judged that the mast cells in the nasal epithelium and in the subepithelial layer play a more important part in the onset of a nasal allergic reaction than do those in the deep layer of the nasal lamina propria.

Important factors in the nasal manifestation of allergy

To elucidate whether or not histamine can be released by antigen from the nasal surface layer in sufficient quantities to produce nasal manifestation of allergy and which among three factors, i.e., the number of surface basophilic cells, the histamine release from these cells, or the mucosal histamine sensitivity, is the most responsible for the degree of nasal allergen provocation, we determined the allergen-induced histamine release from specimens of the mucus-epithelial layer of patients with nasal allergy and also counted the number of basophilic cells in these specimens after staining by Hansel's method. In addition, we evaluated the histamine sensitivity of the mucosa by the end-point test. The net histamine content released from the specimens of the nasal surface ranged from 25.5--310.7 microgram/cm3, which was found to be sufficient to produce nasal manifestation of allergy. Thye correlation coefficients were calculated as the relationships between the degree of provocation reaction and the level of histamine released from the nasal surface, the basophilic cell number, histamine releasability and histamine reactivity. these values were 0.645, 0.440, 0.481, and 0.155, respectively, and, when they were analyzed statistically, the most significant correlations to the degree of provocation reaction were found to be those between the degree of provocation reaction and the histamine content released from the nasal surface, the basophilic cell number, or the histamine releasability and histamine reactivity (p less than 0.01), in that order.

Effects of beclomethasone dipropionate nasal spray on subjective and objective findings in perennial allergic rhinitis

It was the aim of this trial to study the effect of intranasal beclomethasone dipropionate on symptoms and signs of perennial allergic rhinitis in Japanese patients. In a multicenter trial 183 patients, children and adults, were treated with placebo or with 400 microgram beclomethasone dipropionate a day for 2 weeks. The active treatment had an effect on all nasal symptoms: sneezing, nose blowing, and blockage being reduced to 34%, 44% and 63% (P < 0.01) of the values in the placebo group. A considerable carry-over effect was found, suggesting a group comparative design to be preferable for a cross over trial for the study of intranasal steroids. The beclomethasone dipropionate therapy had a significant inhibitory effect on the immediate response to nasal allergen provocation. The number of secretion eosinophils was reduced during treatment, and the appearance of the mucous membrane tended to normalize. Local side effects were few and insignificant. It is concluded that beclomethasone dipropionate is a valuable drug for the treatment of perennial allergic rhinitis.