Fixation with Carnoy's fluid reduces the number of chymase-positive mast cells: not all chymase-positive mast cells are also positive for tryptase

Mast cells in the nasal mucosa can be studied by means of monoclonal antibodies (mAb) against tryptase (T+MC) and chymase (C+MC). Fixation with acetone gives more positive cells than does fixation with Carnoy's fluid. In frozen biopsy specimens of allergic nasal mucosa fixed with acetone, the number of T+MC equals that of C+MC. When fixed with Carnoy's fluid, however, the number of T+MC is larger than the number of C+MC. The decrease in both T+MC and C+MC resulting from fixation with Carnoy's fluid is time-related and depends on the type of mAb used. Carnoy fixation time gives a decrease in the number of C+MC within 1 min, whereas the number of T+MC decreases only after 10 min. Within 1 min, the number of C+MC decreases to a level where continued fixation no longer gives further decreases in the number of cells. Two populations of mast cells can be distinguished here: one sensitive and the other insensitive to Carnoy's fluid. When double-staining is used, fixation with acetone gives three populations of mast cells: one positive for tryptase (T+C-MC), another positive for tryptase and chymase (T+C+MC), and a third one positive for chymase (T-C+MC). These three populations were found in lymph node, spleen, thymus, dermis, lung parenchyma, small intestinal submucosa, and nasal mucosa.

Once daily intranasal fluticasone propionate (200 micrograms) reduces nasal symptoms and inflammation but also attenuates the increase in bronchial responsiveness during the pollen season in allergic rhinitis

BACKGROUND

Fluticasone propionate aqueous nasal spray, a new topical corticosteroid, has been proved to be an effective treatment for seasonal allergic rhinitis.

OBJECTIVES

We studied the effect of fluticasone propionate on nasal symptoms, circulating eosinophils, and nasal inflammation in patients with seasonal allergic rhinitis after high-load pollen exposure. Moreover, we examined its efficacy in preventing the increase in bronchial responsiveness to methacholine (PD20) during the pollen season.

METHODS

We conducted a double-blind, placebo-controlled, parallel-group study in patients who had a history of allergic rhinitis in response to pollens of grass and Parietaria species and were living in northern Italy. After a run-in period of 2 weeks, 24 patients were treated with fluticasone propionate (200 micrograms, once daily), and 26 patients received matched placebo for 6 weeks, starting from the beginning of the pollen season. Assessment of efficacy was based on scores of daily nasal symptoms. Nasal lavage was performed at the end of the season, and differential cell count was expressed as percent of total cells. PD20 methacholine was measured at the beginning and end of the season and after the season had ended.

RESULTS

Fluticasone propionate significantly reduced nasal obstruction, itching, and rhinorrhea. Eosinophils in blood (p < 0.01) and nasal lavage (p < 0.001) were also reduced. Moreover, fluticasone significantly attenuated the decrease in mean PD20 methacholine (from 1.95 to 0.89 mg) compared with placebo (from 1.38 to 0.37 mg: p < 0.01). After the season, no difference in PD20 methacholine was found between treatment groups.

CONCLUSIONS

The results of this study indicate that fluticasone propionate is effective in decreasing nasal symptoms and eosinophil inflammation in patients with seasonal allergic rhinitis after high-load pollen exposure. Our results also demonstrate that treatment with fluticasone propionate partially prevents the increase in bronchial responsiveness provoked by the inhalation of seasonal pollens in allergic rhinitis.

Allergic rhinitis, olfactory disorders and secretory IgA

The authors point out the possible relationship between the biochemical and immunological components of nasal mucus in subjects affected by allergic rhinitis and/or olfactory disorders. Fifty seven subjects (33 F, 24 M) aged between 19 and 73 years, (median age 65 SD 14.60) were studied. Twenty seven of them were normosmic affected by allergic rhinitis and taken as control group, (14 were positive to allergometric tests and/or RAST, while the other 13 were negative), 30 were dysosmic, and subdivided into parosmic (n = 6), anosmic (n = 15) and hyposmic (n = 9) (only one was negative both to allergometric tests and to RAST). In all patients we assessed: nasal mucus (it was analysed for: mucus quantity, pH, protein concentration, K+ concentration and the SIgA antibodies, tested both by radian immunodiffusion and by ELISA), allergometric tests, PRIST, RAST, anterior rhinomanometry, evoked olfactory potential. As regard to allergometric tests, we have no observed statistically significant differences between the control and the dysosmic group, although all the dysosmic patients (except one) were positive both to allergometric tests and to RAST. Total (PRIST) and specific (RAST) IgE values (except for the anosmic subjects who had IgE values moderately higher) were similar to the results obtained by allergometric tests. As regards to nasal secretion quantity, it was reduced (p: n.s.), like the pH (p: n.s.), in the parosmic subjects. On the other hand, proteins concentration of nasal secretion was lowered in hyposmic (p: n.s.) and anosmic (p = 0.05) subjects, while there were no differences between parosmic subjects and control group. The values of SIgA in controls and hyposmic subjects were not too different and similar to those observed by other authors; however they were slightly increased in controls affected by allergic rhinitis with positivity both to RAST and/or allergometric tests (p: n.s.), while they were reduced in the parosmic and significantly in the anosmic patients (p < 0.01). On the basis of that data, the authors conclude that, (though related to a limited case reports) being the secretory IgA values inversely proportional to the gravity of olfactory pathology, a their protective role (if the anatomic-functional substratum is efficient), in the pathologies examined, can be easily hypothesized. Besides, that data highlight that their concentration is slightly decreased in those patients affected by allergic rhinitis, without olfactory disorders (p: n.s.).

A comparative immunological study of vasomotor rhinitis and pollinosis

Differentiation between pollinosis and vasomotor rhinitis creates great diagnostic difficulties. The aim of this study was to conduct comparative immunological clinical studies contrasting these two distinct diseases. Thirty-one subjects with untreated pollinosis and 29 subjects with untreated symptoms of rhinitis were tested, determining their T and B lymphocyte counts and the counts of their subpopulations, the levels of immunoglobulin A, M, G, D and E, both separately and in total, and levels of both basal and whole histamine. The control group was comprised of 30 healthy subjects. The results of this study show that these two diseases differ from each other (p < 0.05) in the recorded levels of basal histamine, total IgE, and IgG, IgM and IgD, as well as the count of T-RFC lymphocytes, T lymphocytes with receptors for Fc IgG and B lymphocytes with superficial receptors for IgG. The most useful laboratory methods for diagnosing the difference between pollinosis and vasomotor rhinitis appear to be the determination of levels of basal histamine and IgD in the blood.

Antigen presenting cells in the nasal mucosa of patients with allergic rhinitis during allergen provocation

BACKGROUND

The role of antigen presenting cells (APC) in allergic rhinitis is underexposed. Allergen presentation to T lymphocytes is probably an important aspect of the pathophysiological mechanism of allergic rhinitis.

OBJECTIVES

The aim of the study was to investigate the presence and dynamics of APC with special emphasis on Langerhans cells (LC) in the nasal mucosa of patients with an isolated grass pollen allergy during an out-of-season 2-week allergen exposure, mimicking the natural grass pollen season.

METHODS

Seventeen patients with isolated grass pollen allergy and four control subjects were challenged daily with allergen during a 2-week period in the winter. Biopsy specimens were obtained once before, six times during and once after the provocation period. Biopsy sections were stained with monoclonal antibodies: OKT6 (CD1a-Langerhans cells), Ki-M6 (CD68-macrophages), L25 (dendritic cells), anti-IgE, HLA-DR and HLA-DQ (Major Histocompatibility Complex Class II-antigen presenting cells), as well as staining with acid phosphatase.

RESULTS

APC with different characteristics are present in the epithelium and lamina propria of the nasal mucosa. The number of LC increased significantly in epithelium and lamina propria. IgE(+)-LC were present in the nasal mucosa and increase during provocation. HLA-DR+ cells with dendritic and lymphocytic morphology and HLA-DQ+ cells were found. The number of these cells increased during provocation in epithelium and lamina propria. The number of HLA-DR+ epithelial cells did not change. A significant increase in the number of Ki-M6+ cells (macrophages) was found in the lamina propria. However, Ki-M6+ cells increased to the same extent in the lamina propria in the control group.

CONCLUSION

APC are influenced by allergen provocation. This study supports the hypothesis that (IgE+) LC are involved in allergic rhinitis. The role macrophages play remains doubtful.

GM-CSF, IL-8, IL-1R, TNF-alpha R, and HLA-DR in nasal epithelial cells in allergic rhinitis

Epithelial cells potentially contribute to airways inflammation by antigen presentation and the production of proinflammatory cytokines. This study investigated the immunocytochemical localization of interleukin-8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 receptor (IL-1R Type I), tumor necrosis factor-alpha receptor (TNF-alpha R; 55kD), and human leukocyte antigen-DR (HLA-DR) on epithelial cells obtained by nasal brushing from 10 patients with allergic rhinitis in season and 15 healthy, nonallergic subjects. Six of the 15 nonallergic asymptomatic subjects had macroscopic evidence of nasal mucosal inflammation, and their brushings contained more than 10% neutrophils ("subclinical inflammation"). In normal control subjects, 8 +/- 7.5% of epithelial cells stained for HLA-DR, approximately one quarter stained for IL-8 and GM-CSF, and about one third stained positive for IL-1R and TNF-alpha R. The findings in subjects with allergic rhinitis in season and with subclinical neutrophilia were similar, and the numbers of cells staining for HLA-DR expression correlated with both neutrophil and lymphocyte content. These findings further support the conclusion that epithelial cells can contribute to inflammatory processes in the nasal mucosa. The findings emphasize the need to identify asymptomatic nasal mucosal inflammation in studies of the nasal mucosa.

Phenotypic and molecular characteristics of nasal mucosal gamma delta T cells in allergic and infectious rhinitis

T cells expressing the T-cell receptor (TCR) gamma delta home in on various epithelia and may play an important role in local immunity to foreign antigens. The nasal mucosa is a potential site for chronic inflammatory diseases, yet little is known about the characteristics of nasal mucosal gamma delta T cells. Using flow cytometry, immunohistochemistry, and RT-PCR, we elucidated the characteristics of nasal mucosal gamma delta T cells in patients with perennial allergic rhinitis (PAR), chronic infective rhinitis (CIR), and seasonal allergic rhinitis (SAR) and in normal subjects. The gamma delta T cells were significantly increased in the nasal mucosa of patients with PAR (PAR, 24.3 +/- 4.5%; CIR, 12.9+/- 2.7%, p < 0.01), unrelated to those in autologous peripheral blood (PAR, 5.6 +/- 0.8%; CIR, 9.6 +/- 2.8%), and they were preferentially distributed in the epithelial compartment (26.7 +/- 2.3%) rather than in the lamina propria (5.4 +/- 2.5%). Of the expanded population of nasal mucosal gamma delta T cells in patients with PAR, CD4+ and CD4-8- gamma delta T cells were selectively increased (p < 0.01). Although nasal intraepithelial gamma delta T cells from all groups of patients and normal subjects dominantly expressed the V gamma 1/V delta 1 genes, and a bias for V gamma 3 gene expression was noted in those of patients with PAR, a significantly larger fraction of nasal mucosal gamma delta T cells in patients with PAR expressed the V gamma 1/V delta 1 TCR (p, 0.01), whereas those of the peripheral blood expressed the V gamma 2/V delta 2 TCR. More than 60% of V gamma 1/V delta 1 TCR+ cells in patients with PAR, were CD45RO+ ("memory cells"), independent of those in their peripheral blood (p < 0.01). Furthermore, a substantial proportion of nasal mucosal gamma delta T cells in patients with PAR synthesized IL-4 and IL-5 but negligible amounts of IFN-gamma. These observations of an increase in the proportions and activation of distinct subsets of nasal mucosal gamma delta T cells and their Th2-type cytokine profile in patients with PAR, unrelated to those in autologous peripheral blood suggest an important role for the oligoclonally expanded expanded nasal mucosal gamma delta T cells in the pathogenesis of PAR.

Allergy and the risk of sudden infant death syndrome. The Members of the New Zealand Cot Death Study Group

BACKGROUND AND OBJECTIVE

There are several sources that suggest that there is a link between allergy and sudden infant death syndrome. We endevavoured to look for evidence of an association between allergic disease and the risk of sudden infant death syndrome (SIDS).

METHODS

A nationwide case-control study covering a region with 78% of all births in New Zealand during 1987-90. Interviews were completed with the parents of 393 (81.0% of total) infants who died from the sudden infant death syndrome (SIDS), and 1592 (88.4% of total) control families who were a representative sample of all hospital births in the study region.

RESULTS

Eczema was reported in 13.9% control infants compared with only 8.0% of the SIDS infants, univariate odds ratio for this in terms of risk for SIDS was 0.56 (95% confidence interval 0.37, 0.84) for infants with eczema compared with those without. This lesser risk for SIDS was unchanged when adjusted for potential confounding factors. The risk of SIDS was not associated with reported cow's milk reactions or a family history of allergic symptoms once adjustments were made for possible confounding factors.

CONCLUSION

Infants with skin disorders identified by their parents as eczema had a low risk for SIDS. Families can be reassured that atopy is not a risk factor for SIDS.

Nasal neutrophilia and release of myeloperoxidase induced by nasal challenge with platelet activating factor: different degrees of responsiveness in atopic and nonatopic subjects

BACKGROUND

Nasal challenge with platelet activating factor (PAF) is able to induce local neutrophilia, with a different degree of responsiveness in atopic subjects and in nonatopic subjects. We investigated whether nasal accumulation of neutrophils induced by PAF is accompanied by the release of neutrophil-derived mediators.

METHODS

Nasal lavages were performed before and after challenge with PAF (500 nmol), lyso-PAF (500 nmol), and saline solution in 10 patients with allergic rhinitis and 10 normal subjects to evaluate changes in neutrophil counts and the release of myeloperoxidase (MPO) and immunoreactive leukotriene B4.

RESULTS

PAF caused neutrophilia, which appeared after 30 minutes in atopic subjects and after 3 hours in nonatopic subjects. Furthermore, when compared with saline insufflation, PAF caused a significant release of MPO in the nasal lavage fluids collected 30 minutes, 3 hours, and 24 hours after challenge in atopic subjects and 3 hours after challenge in nonatopic subjects, with higher values in the former than in the latter. Neutrophil counts correlated with MPO levels in the nasal lavages collected after PAF challenge. A lower degree of neutrophilia was found 3 hours after stimulation with lyso-PAF in both groups of subjects, with a marginal release of MPO in atopic subjects only. No significant increase of immunoreactive leukotriene B4 levels in nasal lavages was found after challenge with either PAF or lyso-PAF.

CONCLUSION

These results indicate that PAF-induced neutrophilia in the nose is accompanied by the release of MPO, which appears earlier and is more marked in atopic subjects than in nonatopic subjects.

The mechanism of bronchial hyperreactivity in allergic rhinitis patients. A light microscopic study on BAL and bronchial biopsy

Epidemiological data indicated that allergic rhinitis often coexists with and may precede the development of reactive airway disease. In particular, ARP with BHR are more likely to develop asthma. However, the pathogenesis of BHR associated with allergic rhinitis is still remains uncertain. Therefore we designed the study on ARP with/without BHR. The aim of this study were to investigate the presence of an inflammatory process in lower respiratory tract in ARP and to relate these changes to airway responsiveness Eleven ARP with BHR (Group I), eleven ARP without BHR (Group II) and two control patients (Control group) were studied. All of the ARP were judged atopic on the basis of positive skin prick test to common inhalant allergens. Bronchial challenges were performed with increasing concentration of M. All the subjects underwent fiberoptic bronchoscopy, BAL and bronchial biopsies were obtained for pathologic examination. The mean total cell and the mean percentage of macrophages, lymphocytes, neutrophils and eosinophils in BAL fluid were in normal range in all groups without any significant differences between the groups. There weren't any correlation between PC20 to M and the total cell counts and percentage counts of these cells. In bronchial biopsy samples, the absolute numbers of lymphocytes, neutrophils, eosinophils and mast cells in the submucosa showed no differences between the three groups. The epithelial shedding was more extensive in ARP than control subjects (p = 0.05). The thickness of the epithelium was prominent in Group I (p < 0.05) but there was no significant differences in the basement membrane thickening between the three groups. We could only find an inverse correlation between PC20 to M and the mast cell counts in the submucosa (r xy:-0.815 p < 0.05). In conclusion, we couldn't observe any prominent morphological changes which indicate that may cause of BHR in ARP except the increased epithelial shedding in Group I. However, the increased epithelial shedding is not a reliable criterion to comment because of the possibility of mechanical damage of bronchial biopsies caused by the forceps.

Dynamics of nasal eosinophils in response to a nonnatural allergen challenge in patients with allergic rhinitis and control subjects: a biopsy and brush study

BACKGROUND

Eosinophils are thought to play an important role in the symptomatology and pathophysiology of allergic rhinitis. Most quantitative studies on eosinophils in nasal mucosa have focused on the dynamics of eosinophils in the acute and late phases of the allergic reaction by using different cell sampling techniques. Little is known about the dynamics of eosinophils during a more prolonged period of allergen exposure and the activation of eosinophils induced by allergen challenge.

OBJECTIVE

The aim of this study was to investigate the dynamics and activation of the eosinophils in the nasal mucosa of patients with an isolated grass pollen allergy during an out-of-season 2-week allergen exposure, mimicking the natural grass pollen season.

METHODS

Seventeen patients with isolated grass pollen allergy and four control subjects were challenged daily with the allergen during a 2-week period in the winter. Nasal brush specimens were obtained before provocation and each day during the provocation period. Biopsy specimens were obtained once before, six times during, and once after the provocation period. Preparations made of nasal brush and nasal biopsy specimens were stained with the monoclonal antibody BMK 13 and Giemsa stain as paneosinophil markers and with the monoclonal antibody EG2 to identify activated eosinophils.

RESULTS

We found significant increases in the total number of eosinophils and the number of activated eosinophils in the epithelium and lamina propria. These increases were most explicit in the second week. BMK 13 was found to be a paneosinophil marker superior to Giemsa staining.

CONCLUSION

Eosinophils are not only involved in the acute and late phases of the allergic reaction but are probably even more involved in the chronic phase.

Chemokines in seasonal allergic rhinitis

Monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 (MCAF/MCP-1), RANTES, and macrophage inflammatory protein (MIP)-1 alpha are chemokines known to activate basophils (MCAF/RANTES) and eosinophils (RANTES/MIP-1 alpha). IL-8 inhibits MCAF-induced histamine release from basophils. We questioned whether a relationship exists between the levels of these chemokines and various inflammatory mediators released from mast cells, eosinophils, and basophils as assessed in nasal secretions obtained from patients during the allergy season and out of season. Samples were assessed for MCAF/MCP-1, RANTES, MIP-1 alpha, IL-8, histamine, tryptase and eosinophil cationic protein (ECP) in three subject groups: subjects with allergic rhinitis (n = 18), atopic subjects without rhinitis (n = 9), and healthy individuals (n = 6). Statistically significant differences were apparent only in the subjects with symptoms as follows. MCAF/MCP-1 increased during the season from 336 +/- 47 pg/ml to 829 +/- 137 pg/ml (p < 0.001), whereas IL-8 decreased from a baseline of 1932 +/- 335 pg/ml to 1070 +/- 202 pg/ml (p < 0.028). The ratio of IL-8 to MCAF/MCP-1 decreased during the symptomatic season from the baseline of 6.66 +/- 1.06 seen during winter to 1.3 +/- 0.22 during ragweed season (p < 0.001). Histamine increased from 6.3 +/- 1.5 to 89 +/- 15.5 ng/ml (p < 0.001), ECP increased from 20.6 +/- 6.4 to 237.1 +/- 50.2 ng/ml (p < 0.001), and tryptase increased from 2.34 +/- 0.6 to 9.7 +/- 2.3 U/ml (p < 0.001). Most samples did not have detectable quantities of MIP-1 alpha or RANTES. We also found a correlation between the level of MCAF/MCP-1 and IL-8 and the level of histamine or IL-8 and ECP. Our results suggest that the chemokines MCAF/MCP-1 and IL-8 may participate in the pathogenesis of allergic rhinitis, contributing to the attraction of the proinflammatory cells and mediator release, which might be very important during the late phase of the allergic reaction. Furthermore, the ratio of certain chemokines, such as MCAF/MCP-1 and IL-8 may reflect the magnitude of the reaction, as does the presence of histamine and ECP.

Effect of interleukin-5 and granulocyte-macrophage colony stimulating factor on in vitro eosinophil function: comparison with airway eosinophils

Eosinophils are hypothesized to be crucial in the development of allergic airway inflammation; however, the actual mechanisms that determine their inflammatory activity are still largely undefined. To investigate the factors that regulate eosinophil function in allergic airway disease, we have previously used segmental bronchoprovocation with allergen to study ex vivo eosinophil function. To determine whether the functional changes associated with airway eosinophils obtained by bronchoalveolar lavage 48 hours after antigen challenge are caused by exposure to airway-generated cytokines, normodense blood eosinophils were cultured in vitro with recombinant human interleukin-5 (IL-5) or granulocyte-macrophage colony stimulating factor (GM-CSF). The effect of cytokine exposure was then evaluated on selected cell functions. In vitro incubation with these cytokines for 24 hours significantly increased eosinophil membrane expression of CD18 and CD11b compared with culture in medium alone or eosinophils obtained by bronchoalveolar lavage. N-formyl-methionyl-leucyl-phenylalanine-stimulated superoxide anion generation was slightly but significantly enhanced by incubation with IL-5 but not with GM-CSF. In addition, spontaneous adhesion to human umbilical vein endothelial cell monolayers was increased after exposure to both IL-5 and GM-CSF. However, activated adhesion was enhanced only by culture with IL-5 and stimulation with N-formyl-methionyl-leucyl-phenylalanine. The magnitude of functional changes after in vitro preincubation of eosinophils with these cytokines did not achieve levels of superoxide anion and adhesion noted with airway eosinophils obtained after segmental bronchoprovocation with allergen. These observations raise the possibility that the contribution of IL-5 and GM-CSF to phenotypic changes of airway eosinophils is principally to enhance survival and expression of adhesion proteins. These data also suggest that, in addition to the generation of proinflammatory cytokines, other factors contribute to phenotypic changes in eosinophils as they migrate from the blood to the airway.

Nasal immunotherapy to Parietaria: evidence of reduction of local allergic inflammation

Studies over 10 yr have demonstrated local nasal immunotherapy (LNIT) to be an effective treatment for rhinitis due to pollens and mites. The aim of our work was to investigate the effects of LNIT on the local inflammatory phenomena, employing the model of nasal allergenic challenge, since no evidence has been yet provided about LNIT effects on the events due to allergic reactions. We evaluated, in addition, the possible effects of LNIT on some systemic immunologic parameters and its clinical efficacy. The study involved a double-blind, placebo-controlled trial of preseasonal immunotherapy with Parietaria in 20 adults. A significant reduction of symptoms, inflammatory infiltration, and intercellular adhesion molecule-1 (ICAM-1) expression on epithelial cells after nasal challenge was evidence as long-lasting effect. No changes in serum allergen-specific IgE, IgG, and soluble eosinophil cationic protein were detected, whereas an unexpected increase of soluble ICAM-1 was found in the placebo group only. The treatment was well tolerated and a significant clinical improvement under natural allergenic exposure was observed in the active group. The present study provides, for the first time, evidence that LNIT is able to modulate the nasal allergic inflammation.

Loratadine reduces allergen-induced mucosal output of alpha 2-macroglobulin and tryptase in allergic rhinitis

BACKGROUND

Despite the wide use of antihistamines in the treatment of allergic rhinitis, little is known about effects of these drugs on airway mucosal indices, which specifically reflect either mast cell release activity (tryptase) or microvascular-epithelial exudation of bulk plasma (alpha 2-macroglobulin).

OBJECTIVE

This study, involving subjects with seasonal allergic rhinitis, examines the effects of loratadine treatment on allergen-induced nasal mucosal output of tryptase and alpha 2-macroglobulin. Effects on nasal symptoms and eosinophils are also examined.

METHODS

Placebo and loratadine (20 mg) were given orally once daily for 5 days at 6-week intervals. Nasal diluent and allergen challenges were carried out on day 5. The mucosa was lavaged with saline solution after each challenge, and nasal lavage fluid levels of tryptase and alpha 2-macroglobulin were determined. Nasal symptoms were scored, and nasal peak expiratory flow rates were measured. Superficial cells (eosinophils) were obtained with a brush device before and 24 hours after the allergen challenges.

RESULTS

Allergen dose-dependently increased the nasal symptoms and the lavage fluid levels of alpha 2-macroglobulin and tryptase. Allergen also reduced the nasal peak expiratory flow rates. Loratadine inhibited the exudation of alpha 2-macroglobulin and reduced tryptase levels, nasal symptoms, and obstruction, but did not affect the number of eosinophils.

CONCLUSION

The inhibitory effects of loratadine on nasal lavage fluid levels of alpha 2-macroglobulin suggest that histamine, through effects on microvascular H1-receptors, mediates allergen challenge-induced exudation of bulk plasma in acute allergic rhinitis. The reduced lavage fluid levels of tryptase suggest either that loratadine directly attenuates mast cell release activity or that loratadine, through inhibition of the exudation process, simply attenuates luminal entry of tissue solutes (in this case, tryptase).

Study of nasal cytology in atopic patients after nasal allergen challenge

In order to study the normal and pathological inflammatory cell population in nasal secretions, nasal microsuction has been performed in 18 atopic patients and 10 healthy volunteers after nasal allergen and/or PBS challenge. After cytospin, the samples have been stained with May-Grünwald-Giemsa solution. Three hundred inflammatory cells have been counted by light microscopy, and the percentage of each cell type has been calculated. Results show that only a significant increase (p < 0.01) in the percentage of eosinophils 1-10 h after nasal allergen challenge occurs. In general, this finding correlates well with the symptom of nasal obstruction as measured by passive anterior rhinomanometry (PAR) during the late phase, but not with the number of sneezes. In agreement with the literature, late-phase nasal obstruction is shown to be accompanied by an increase in the percentage of eosinophils in nasal secretions. The potential role of eosinophils in the pathogenesis of the late phase in the inflammatory events after nasal allergen challenge has again been confirmed by our study. This study further confirms the usefulness of nasal microsuction as a sampling technique, providing uniform and adequate nasal cytological specimen for the analysis of nasal cytology.

sVCAM-1 levels after segmental antigen challenge correlate with eosinophil influx, IL-4 and IL-5 production, and the late phase response

Evidence from in vitro studies suggests a potential role for vascular cell adhesion molecule-1 (VCAM-1) in eosinophil trafficking. We hypothesized that induction of VCAM-1 occurs in the lung during IgE-mediated airway inflammation in humans. The technique of segmental antigen provocation followed by bronchoalveolar lavage (BAL) at 24 h was used to study 27 ragweed-allergic asthmatics (AA) and 18 atopic nonasthmatics (ANA). Total and differential cell counts were performed, and IL-4, IL-5, and soluble (VCAM) (sVCAM) levels in concentrated BAL fluid were measured by ELISA. A large increase in sVCAM levels after segmental challenge in both AA and ANA (1.79 +/- 0.31 to 139.39 +/- 68.58 ng/ml, p < 0.0005 and 2.85 +/- 0.80 to 98.25 +/- 77.35 ng/ml, p < 0.05, respectively) was observed. BAL IL-4 and IL-5 also increased after challenge (IL-4: 51.7 +/- 17.72 to 150.1 +/- 58.82 pg/ml, 0.05 < p < 0.10, n = 20 for AA, and 36.6 +/- 9.05 to 116.8 +/- 51.5 pg/ml, 0.05 < p < 0.10, n = 15 for ANA; IL-5: 0 to 2.67 +/- 1.62 ng/ml, p < 0.01, n = 16 for AA, and 0 to 2.87 +/- 2.16 ng/ml, 0.05 < p < 0.10, n = 10 for ANA). In both groups, the majority of the increase in sVCAM, IL-4, and IL-5 was accounted for by subjects who displayed a dual phase response after whole-lung antigen inhalation. This fact, plus the strong correlation observed between postchallenge sVCAM, IL-4, and IL-5 levels and eosinophil influx, suggests that VCAM, IL-4, and IL-5 play important roles in the recruitment of eosinophils to the lung of humans after antigen challenge.

Phenotype of cells positive for interleukin-4 and interleukin-5 mRNA in allergic tissue reactions

We have investigated the phenotype of cells positive for IL-4 and IL-5 mRNA in the nasal mucosa of subjects with allergic rhinitis and in bronchoalveolar lavage and bronchial biopsies from atopic asthmatic subjects. The method employed was immunochemistry followed by in situ hybridization using either 35S- or digoxigenin-labelled riboprobes. With nasal and bronchial tissue, this double ICC/ISH method revealed that more than 70% of IL-4 and IL-5 mRNA+ cells were T cells. The remaining IL-4 and IL-5 signals were co-localized to tryptase-positive mast cells and EG2+ eosinophils. Occasional IL-4 and IL-5 mRNA cells were observed in non-asthmatic control subjects, the large majority being CD3+ cells. These results indicate that CD3+ cells are the principal cellular source of IL-4 and IL-5 transcripts in atopic asthma and allergic rhinitis.

Changes in allergic inflammation associated with successful immunotherapy

Allergen injection immunotherapy in selected patients is effective and has wide ranging anti-inflammatory effects. These include modulation of serum (and presumably local) IgE and IgG antibody responses, a reduction in mast cell numbers in the target organ and inhibition of mast cell mediator release. Tissue eosinophilia and eosinophil activation are also reduced. We have compared and contrasted the effects of immunotherapy and topical corticosteroids on allergen-induced late nasal responses. Both treatments inhibit allergen-induced late nasal symptoms and associated CD4+ T cell and eosinophil recruitment, possibly by distinct mechanisms. Whereas topical corticosteroids may act by suppressing cytokine mRNA expression for Th2-type cytokines, particularly interleukin-4, immunotherapy induces a local Th1 response with an increase in interferon-gamma.

The significance of isoallergenic variations in present and future specific immunotherapy

The isoallergenic variation of the tree pollen major allergens has been studied by 2D gel electrophoresis, and by analysis of several recombinant clones. The studies have included both antibody-based and T cell stimulation assays. Bet v 1, the major allergen of birch, forms at least 24 spots when conventional extracts are analyzed by 2D gel electrophoresis. Comparison of Bet v 1-encoding DNA sequences reveals a considerable number of amino acid substitutions. This sequence variation can theoretically account for the number of spots observed in 2D gels. Whereas pools of serum from allergic individuals and monospecific antibodies raised in rabbits bind to most if not all spots in 2D gels, analyses of individual serum and/or murine monoclonal antibodies show individual patterns of reactivity with various subsets of spots. These observations point to a model in which amino acid substitutions induce local perturbations of the allergen surface, causing differences in epitope structure. Furthermore, analysis of pollen from individual trees shows that each tree produces individual subsets of Bet v 1 spots. When analyzed in stimulation assays, T cell clones also display differences in reactivity to different isoallergens. In conclusion, we have shown that Bet v 1 is heterogeneous, and that individual trees produce various subsets of isoallergens which display differences in reactivity both towards antibodies and T cells. A careful selection of isoform may therefore be of major importance if recombinant allergens or synthetic peptides are to be used for conventional immunotherapy.

Correlations between complaints, inflammatory cells and mediator concentrations in nasal secretions after nasal allergen challenge and during natural allergen exposure

A quantitative determination of the inflammatory mediators was performed and correlated with complaints and the measurement of the inflammatory cells in nasal secretions of 18 seasonal allergic rhinitis patients (group 1) outside the pollen season and 40 symptomatic patients (group 2) with seasonal allergic rhinitis during the pollen season. Ten nonallergic subjects (group 3) were also studied as a normal control group. In group 1, 17 (94%) out of 18 patients had an immediate response of nasal symptoms accompanied by a significant increase of histamine, leukotriene C4 (LTC4), and tryptase 5 min after nasal allergen challenge (NAC). One hour later, a simultaneous increase was seen both in the percentage of the eosinophils and in the eosinophil cationic protein (ECP) concentration. The eosinophil count reached a peak 2 h after NAC with a duration of 8 h, while the highest ECP level was reached only after 24 h with no clear-cut plateau. In group 2, a high percentage of eosinophils was observed. Mostly one observed significantly (p < 0.01) higher concentrations of ECP, LTC4 and histamine but not of tryptase than the baseline values of group 1. The authors concluded that during the pollen season allergic rhinitis reflects mainly a chronic state of allergic inflammation of the nasal mucosa involving various inflammatory components induced by one or more episodes of early-phase type allergic reaction. Infiltration of eosinophils and consequently release of the various late-phase inflammatory mediators into the nasal secretions are certainly believed to be the predominant pathophysiologic condition in the patients.

Effect of intranasal azelastine and beclomethasone dipropionate on nasal symptoms, nasal cytology, and bronchial responsiveness to methacholine in allergic rhinitis in response to grass pollens

BACKGROUND

We compared the effect of nasal azelastine (0.56 mg/day), nasal beclomethasone dipropionate (BDP, 200 micrograms/day) and matched placebo on seasonal symptoms, nasal cytology, and the increase in bronchial responsiveness occurring during pollen season in a group of subjects with history of allergic rhinitis to grass pollens only.

METHODS

The study was completed by nine subjects in the azelastine group, 13 subjects in the BDP group, and 13 subjects in the placebo group. Treatments were randomly administered for 6 weeks. Each subject recorded daily nasal, eye and chest symptoms and additional treatment requirement for the entire pollen season. Each subject performed nasal lavage 4 weeks into the pollen season. Bronchial responsiveness to methacholine was measured before and 4 weeks into the pollen season. Response was expressed as provocative dose causing a 20% fall in forced expiratory volume in 1 second in micromoles.

RESULTS

Azelastine-treated subjects had significantly fewer nasal symptoms during week 4 (p < 0.05), and BDP-treated subjects had fewer nasal symptoms during week 4 (p < 0.05) and week 5 (p < 0.05) compared with subjects given placebo. Both treatments significantly reduced the need for additional medications. BDP, but not azelastine, treatment significantly reduced the percent of eosinophils recovered in nasal lavage (p < 0.05). Neither azelastine nor BDP protected against the increase in bronchial responsiveness to methacholine occurring during the pollen season.

CONCLUSION

We demonstrated that both azelastine and BDP are effective treatments for nasal symptoms of seasonal allergic rhinitis after 4 weeks of therapy. However, we were not able to demonstrate an antiinflammatory activity of nasally administered azelastine. Nasal therapy with azelastine and BDP did not block the increase in bronchial responsiveness to methacholine caused by seasonal allergen exposure.

Monitoring nasal allergic inflammation by measuring the concentration of eosinophil cationic protein and eosinophils in nasal secretions

Quantitative measurement of the eosinophil cationic protein (ECP) concentration and the percentage of eosinophils in nasal secretions has greatly improved our understanding of the inflammatory process after natural allergen exposure. ECP and eosinophils were measured in the nasal secretions of 40 symptomatic patients with seasonal allergic rhinitis during the pollen season. Results showed a significant relationship between a high concentration of ECP (median: 410 ng/g, range: 6-2380 ng/g) and a high percentage of eosinophils (median: 13.5%, range: 1-85%). This quantitative study again demonstrated that infiltration by eosinophils and release of ECP play a key role in allergic rhinitis. It also suggests that the combined measurement of the percentage of eosinophils together with the ECP concentration in nasal secretions seems to be a very useful model in monitoring and assessing the condition of chronic nasal inflammation in patients with allergic rhinitis.

Nasal histamine challenge in nonallergic and allergic subjects evaluated by acoustic rhinometry

Nasal patency shows spontaneous variations but is influenced by a number of factors like exercise and allergic conditions. Nasal histamine challenge has been used to define nasal hypersensitivity. We have applied acoustic rhinometry as a new objective method to study the spontaneous variations of the nasal mucosa and its response to histamine challenge in 12 nonallergic subjects and 12 subjects with nasal allergy to pollen, but out of the pollen season. Measurements of the minimum cross-sectional area and the volume of the nasal cavities were done every 15 min for 6 h. More pronounced spontaneous variations, defined by the coefficient of variation of the measurements, were encountered in the allergic than in the nonallergic subjects, especially with regard to the minimum cross-sectional areas in the nasal cavities (P < 0.02). Allergic subjects showed increased sensitivity to histamine, as compared with nonallergic subjects, during low-concentration (0.1%) challenge (P < 0.05) and a prolonged effect of histamine challenge (P = 0.01). Antihistamine (cetirizine) had a significant effect on the histamine-induced symptoms and decrease of nasal dimensions during histamine challenge, but no significant effect on pollen-induced changes. In the allergic group, the decrease in minimum area during allergen provocation correlated with the level of specific IgE (r = 0.81; P = 0.0015).