Reticular basement membrane (RBM) thickness and airway responses to inhaled methacholine (MCh) were studied in perennial allergic asthma (n = 11), perennial allergic rhinitis (n = 8), seasonal allergic rhinitis (n = 5), and chronic obstructive pulmonary disease (COPD, n = 9). RBM was significantly thicker in asthma (10.1 +/- 3.7 microm) and perennial rhinitis (11.2 +/- 4.2 microm) than in seasonal rhinitis (4.7 +/- 0.7 microm) and COPD (5.2 +/- 0.7 microm). The dose (geometric mean) of MCh causing a 20% decrease of 1-s forced expiratory volume (FEV(1)) was significantly higher in perennial rhinitis (1,073 microg) than in asthma (106 microg). In COPD, the slope of the linear regression of all values of forced vital capacity plotted against FEV(1) during the challenge was higher, and the intercept less, than in other groups, suggesting enhanced airway closure. In asthma, RBM thickness was positively correlated (r = 0.77) with the dose (geometric mean) of MCh causing a 20% decrease of FEV(1) and negatively correlated (r = -0.73) with the forced vital capacity vs. FEV(1) slope. We conclude that 1) RBM thickening is not unique to bronchial asthma, and 2) when present, it may protect against airway narrowing and air trapping. These findings support the opinion that RBM thickening represents an additional load on airway smooth muscle.
Very few double-blind trials of oral immunotherapy have been reported. The majority of these have been performed with pollen extracts and the results have often been equivocal. The major weaknesses of these studies have been the short periods of the trials, the low doses of allergen employed and inadequate evaluation of efficacy. The present study has involved a placebo-controlled double-blind trial of oral immunotherapy for three years with Dermatophagoides pteronyssinus at relatively high doses in 18 paediatric patients. Throughout the trial clinical parameters (symptom and medication scores) and immunological parameters (specific IgE, IgG1 and IgG4 levels) were monitored in order to assess the safety and efficacy of the treatment. The treatment was well tolerated by all patients and no side-effects were experienced. Clinical improvement was evident after the second year of therapy and this was confirmed by a significant reduction in conjunctival reactivity assessed by a specific conjunctival provocation test. In addition, there were significant changes in the immunological parameters with a reduction in specific IgE and increased levels of IgG4 and IgG1, results in keeping with previous studies of oral and subcutaneous immunotherapy. Although the results do not provide an explanation of the basis of successful oral immunotherapy, they clearly demonstrate the efficacy and safety of the treatment and suggest that it may be a useful and more acceptable alternative for patients than the traditional subcutaneous immunotherapy.
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.
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