Pathogenesis of rhinitis.

Rhinitis is a heterogeneous condition that has been associated with inflammatory responses as in allergic rhinitis but can also occur in the absence of inflammation such as in so-called idiopathic (previously 'vasomotor') rhinitis. Allergic rhinitis affects approximately one in four of the population of westernized countries and is characterized by typical symptoms of nasal itching, sneezing, watery discharge and congestion. The intention of this review is to illustrate key concepts of the pathogenesis of rhinitis. Imbalance in innate and adaptive immunity together with environmental factors is likely to play major roles. In allergic rhinitis, initial allergen exposure and sensitization involves antigen-presenting cells, T and B lymphocytes and results in the generation of allergen-specific T cells and allergen-specific IgE antibodies. On re-exposure to relevant allergens, cross-linking of IgE on mast cells results in the release of mediators of hypersensitivity such as histamine and immediate nasal symptoms. Within hours, there is an infiltration by inflammatory cells, particularly Th2 T lymphocytes, eosinophils and basophils into nasal mucosal tissue that results in the late-phase allergic response. Evidence for nasal priming and whether or not remodelling may be a feature of allergic rhinitis will be reviewed. The occurrence of so-called local allergic rhinitis in the absence of systemic IgE will be discussed. Non-allergic (non-IgE-mediated) rhinitis will be considered in the context of inflammatory and non-inflammatory disorders.

Local and systemic effects of cat allergen nasal provocation.

BACKGROUND: Cat allergen is widely distributed in homes and schools; allergic sensitization is common. OBJECTIVE: To develop a model of cat allergen nasal challenge to establish dose-response and time-course characteristics and investigate local and systemic biomarkers of allergic inflammation. METHODS: Nineteen cat-allergic individuals underwent titrated nasal challenge, range 0.243 to 14.6 µg/mL Fel d1, and matched diluent-only provocation. Clinical response to 8 h was assessed by symptom scores and peak nasal inspiratory flow (PNIF). Nasal fluid was collected using polyurethane sponges and analysed by ImmunoCAP and multiplex assays. Whole blood flow cytometry for basophil surface CD63, CD107a, and CD203c was carried out at baseline and 6 h post-challenge. RESULTS: A dose-response to allergen was seen in symptom scores and PNIF, maximal at 10 000 BU/mL (4.87 µg/mL Fel d1), P < 0.0001 vs. diluent. Nasal fluid tryptase was elevated at 5 min after challenge (P < 0.05 vs. diluent); eotaxin, IL-4, -5, -9, and -13 were increased at 8 h (P < 0.05 to P < 0.0001 vs. diluent); TSLP was undetectable; IL-10, IL-17A, and IL-33 were unchanged compared to diluent challenge. Nasal fluid IL-5 and IL-13 correlated inversely with PNIF after challenge (IL-5, r = -0.79, P < 0.0001; IL-13, r = -0.60, P = 0.006). Surface expression of CD63 and CD107a was greater at 6 h than at baseline, both in the presence (both P < 0.05) and absence (CD63, P < 0.01; CD107a, P < 0.05) of in vitro allergen stimulation; no changes were seen on diluent challenge day. CONCLUSIONS: Cat allergen nasal challenge produces local and systemic Th2-driven inflammatory responses and has potential as a surrogate outcome measure in clinical trials.

Effect of grass pollen immunotherapy on clinical and local immune response to nasal allergen challenge.

RATIONALE: Nasal allergen provocations may be useful in investigating the pathophysiology of allergic rhinitis and effects of treatments. OBJECTIVE: To use grass pollen nasal allergen challenge (NAC) to investigate the effects of allergen immunotherapy in a cross-sectional study. METHODS: We studied nasal and cutaneous responses in untreated subjects with seasonal grass-pollen allergic rhinitis (n = 14) compared with immunotherapy-treated allergics (n = 14), plus a nonatopic control group (n = 14). Volunteers underwent a standardized NAC with 2000 biological units of timothy grass allergen (equivalent to 1.3 µg major allergen, Phl p5). Nasal fluid was collected and analysed by ImmunoCAP and multiplex assays. Clinical response was assessed by symptom scores and peak nasal inspiratory flow (PNIF). Cutaneous response was measured by intradermal allergen injection. Retrospective seasonal symptom questionnaires were also completed. RESULTS: Immunotherapy-treated patients had lower symptom scores (P = 0.04) and higher PNIF (P = 0.02) after challenge than untreated allergics. They had reduced early (P = 0.0007) and late (P < 0.0001) skin responses, and lower retrospective seasonal symptom scores (P < 0.0001). Compared to untreated allergics, immunotherapy-treated patients had reduced nasal fluid concentrations of IL-4, IL-9 and eotaxin (all P < 0.05, 8 h level and/or area under the curve comparison), and trends for reduced IL-13 (P = 0.07, area under the curve) and early-phase tryptase levels (P = 0.06). CONCLUSIONS: Nasal allergen challenge is sensitive in the detection of clinical and biological effects of allergen immunotherapy and may be a useful surrogate marker of treatment efficacy in future studies.

Long-Term Effect of Sublingual and Subcutaneous Immunotherapy in Dust Mite-Allergic Children With Asthma/Rhinitis: A 3-Year Prospective Randomized Controlled Trial.

BACKGROUND AND OBJECTIVE: Specific allergen immunotherapy is the only treatment modality that might change the natural course of allergic diseases in childhood. We sought to prospectively compare the long-term clinical and immunological effects of sublingual (SLIT) and subcutaneous (SCIT) immunotherapy compared with pharmacotherapy alone. METHODS: In this single-center, prospective randomized controlled trial, 48 children with mild persistent asthma with/without rhinitis, monosensitized to house dust mites (HDMs) were followed for 3 years. At baseline and years 1 and 3 of follow-up, patients were evaluated and compared for total rhinitis (TRSS) and asthma (TASS) symptom scores, total symptom scores (TSS), total medication scores (TMS), safety profiles, skin-nasal-bronchial reactivity, and immunological parameters. RESULTS: A significant reduction was observed in TASS for both HDM-SCIT and HDM-SLIT at year 3 of treatment compared with baseline and controls (P<.05 for both), with significant improvement in rhinitis symptoms for both groups compared with controls (P=.01 for both). TSS decreased significantly in both HDM-SCIT and HDM-SLIT at year 3 compared with baseline (P=.007 and P=.04, respectively) and controls (P<.01 for both). A significant reduction in TMS was observed in HDM-SCIT and HDM-SLIT compared with baseline and controls (P=.01 in all cases), with a reduction in skin reactivity to HDM (P<.05). Finally, a significant increase in allergen specific IgG4 was observed in the SCIT group at year 3 compared with baseline, the SLIT group, and controls (P<.001 in all cases). CONCLUSIONS: HDM-sensitized asthmatic children treated for at least 3 years with either SCIT or SLIT showed sustained clinical improvement.

Reduced T-bet in addition to enhanced STAT6 and GATA3 expressing T cells contribute to human allergen-induced late responses.

BACKGROUND: T-bet and GATA-3 are transcriptional factors involved in Th1 and Th2 cell differentiation, although their concomitant roles at protein levels in target organs during human allergic disease have not been assessed. OBJECTIVES: We investigated the expression of T-bet and GATA-3 in nasal and cutaneous models of Th2 (grass-pollen allergen) and a cutaneous model of Th1 (PPD) responses in man. METHODS: Nasal biopsies were obtained at 8 h and skin biopsies at 8 and 48 h after allergen and PPD challenges, respectively, from 10 allergic rhinitics and 6 non-atopic controls. T cells were assessed using immunofluorescence microscopy. RESULTS: There were increases in CD3(+)STAT6(+)cells (P = 0.01 for nose and skin) and CD3(+)GATA3(+)cells (P = 0.03 for skin) in response to allergen compared with diluent in allergics. When compared with non-atopics after allergen challenge the difference between the two groups was also significant for CD3(+)STAT6(+) (P = 0.001 and 0.03) and for CD3(+)GATA3(+)cells (P = 0.04 and 0.001) for nose and skin respectively. Following PPD challenge CD3(+)STAT4(+)cells and CD3(+)T-bet(+)cells increased in both groups compared with diluent (P = 0.02 and 0.03 for both TFs), whereas only CD3(+)T-bet(+) cells were significantly greater in non-atopics compared with allergics (P = 0.04). The ratio of GATA3(+):T-bet(+) T cells in allergen-induced responses was significantly greater in the allergics (P = 0.008 and 0.01 nose and skin respectively), whereas the ratio of T-bet:GATA3(+)T cells was significantly higher in the non-atopics during PPD-induced responses (P = 0.003). CONCLUSIONS AND CLINICAL RELEVANCE: Dysregulation of Th1 transcription may contribute to heightened expression of STAT6 and GATA3 leading to exaggerated Th2-driven manifestations of allergic disease.

Clinical efficacy and immunological mechanisms of sublingual and subcutaneous immunotherapy in asthmatic/rhinitis children sensitized to house dust mite: an open randomized controlled trial.

BACKGROUND: In children, the clinical efficacy and immunological mechanisms of sublingual immunotherapy (SLIT) compared with subcutaneous immunotherapy (SCIT) is still to be elucidated. OBJECTIVES: To compare SLIT, SCIT and pharmacotherapy in relation to clinical efficacy and immunological mechanisms that govern its effect in asthmatic/rhinitis children who were sensitized to house dust mite (HDM). METHODS: In this single centre, prospective, randomized, controlled, open labelled, three parallel group trial, 48 patients mono-sensitized to HDM were randomized to receive either SLIT (n=16), SCIT (n=16) or pharmacotherapy alone (n=16). Symptom, medication and visual analogue score (VAS) were collected and bronchial-nasal hyper-reactivity, skin prick tests, total-specific IgE were performed at baseline and 12 months after treatment. In addition, peripheral blood mononuclear cells were cultured with recombinant Der p 1 and Bet v 1 extracts and allergen-specific IL-4, IL-5, IL-13, IFN-gamma, IL-10, and TGF-beta secretions were measured. RESULTS: SLIT and SCIT demonstrated a significant reduction of total rhinitis and asthma symptom score, total medication score, VAS and skin reactivity to HDM (P<0.05) when compared with pharmacotherapy. A significant reduction of serum-specific HDM-IgE in SCIT and SLIT were observed. Moreover, titrated nasal provocative dose significantly increased in both immunotherapy groups when compared with the pharmacotherapy group. No adverse effects were reported in SLIT, while two patients demonstrated serious adverse events in SCIT. After 1 year of treatment, Der p 1-driven IL-10 significantly increased in SLIT compared with pharmacotherapy, whereas Bet v 1-driven TGF-beta (negative control) increased significantly in SLIT only. No changes were observed for Th1-Th2 cytokines. CONCLUSION: Both SLIT and SCIT demonstrated clinical improvement compared with pharmacotherapy in asthma/rhinitis children sensitized to HDM.

Clinical and immunologic features of pediatric patients with common variable immunodeficiency and respiratory complications.

BACKGROUND: Common variable immunodeficiency (CVID) is the term used to describe a heterogeneous group of B-cell deficiency syndromes characterized by hypogammaglobulinemia, impaired antibody production, and recurrent bacterial infections. OBJECTIVES: To determine the clinical manifestations and perform an immunological analysis of pediatric CVID patients suffering from respiratory complications. METHODS: The records of 10 patients with CVID who were followed up from 1992 to 2005 (6 males and 4 females) with a median (interquartile range) age of 13.9 (10.4-19.4) years were reviewed. All patients met the standard criteria set for CVID. RESULTS: Median total serum levels of immunoglobulin (Ig) G, IgM, and IgA in mg/dL were 383.5 (239.2-574.5), 32.5 (17.0-117.0), and 12.5 (5.0-30.7), respectively. Median age at the onset of symptoms, at CVID diagnosis, and on starting intravenous Ig therapy was 4.0 (0.8-6.2), 9.4 (6.7-11.3), and 9.1 (7.0-11.6) years, respectively. Associated disorders were recurrent infections (100%), bronchiectasis (90%), and growth failure (80%), whereas malabsorption, malignant neoplasm, inflammatory bowel disease, and autoimmune disorders were less common. All bronchiectatic patients had a low percentage of B cells, with an average of 4% (range, 1%-7%). The characteristic computed tomography finding in patients with CVID was a multilobar pattern. Malignant neoplasm developed an average of 11.5 (range, 6.5-20.2) years after the diagnosis of CVID was made. CONCLUSION: Recurrent respiratory infection should be evaluated to rule out CVID. Early diagnosis and intravenous Ig replacement therapy may reduce the frequency of respiratory infection. Low levels of serum Ig and percentage of B lymphocytes at diagnosis are important parameters for identifying patients at risk of structural lung damage.