Allergen inhalation challenge induces decrease of serum neutral endopeptidase (NEP) in asthmatics

There is accumulating evidence that tachykinins are implicated in inflammation, including asthma. Therefore, we hypothesized that the neutral endopeptidase (NEP), under challenge conditions, could be affected. Serum from 21 asthmatics and six healthy volunteers was sampled before, 30, and 120 min after allergen challenge. NEP-IR was determined using an ELISA and was found in all subjects. Compared to prechallenge, no difference was seen between asthmatics and controls; however, under challenge conditions, NEP-IR in asthmatics was significantly lower (30 min, P = 0.058; 120 min, P = 0.0017, respectively). This finding supports indirectly the hypothesis that tachykinins are released during allergen exposure, and suggests a regulatory role of NEP.

Decrease in CD23+ B lymphocytes and clinical outcome in asthmatic patients receiving specific rush immunotherapy

Rush immunotherapy (RIT) has been documented as useful in the treatment of patients with allergic bronchial asthma. To investigate the mechanisms of its action, we studied changes in the serum levels of total IgE, allergen-specific IgE and IgG4, and expression of CD23 on peripheral blood B cells in patients receiving RIT. Twenty patients with perennial bronchial asthma were evaluated before the beginning of RIT, as well as 6 weeks and 6 months later. Compared to pretreatment values, the level of Der-p-specific IgG4 and IgE significantly increased after 6 weeks and 6 months of RIT, while the total serum IgE remained unchanged. Furthermore, after 6 months of RIT, the percentage of CD23+B cells and its CD23 receptor density significantly decreased. Since the symptom score improved and the need for medication decreased, we evaluated RIT as a useful procedure. After 6 months, 30% of patients did not have an asthma attack, with no medication in the last month, while 10% of them were asthma free for the last 3 months. No significant correlation between the clinical improvement, and in vitro changes was found. Furthermore, the observed in vitro changes were not significantly different in patients who responded with clinical improvement, compared to those with unchanged intensity of asthma. In conclusion, during specific RIT we found a significant increase in Der-p-specific IgE and IgG4 antibodies, as well as a moderate decrease in CD23+ B cells and its CD23 receptor density. These findings suggest a change in the lymphokine profile of patients receiving specific immunotherapy, and that the inhibition of IL-4-induced B cell stimulation may be hypothesized as the most important mechanism.

Characterization and partial purification of the Croatian national standard Dermatophagoides pteronyssinus allergen extract

Lyophilized Dermatophagoides pteronyssinus (Der p) allergen extract (AE) and partially purified Der p extract (PAE) were prepared and characterized. Partial purification of AE was performed by gel filtration on Sephadex G-100 and Sephacryl S-300. Crossed immunoelectrophoresis (CIE) disclosed the same precipitating lines in AE and PAE preparations. The relative potencies of AE and PAE were determined and compared with the WHO International Standard for Der p by the RAST inhibition method. The potencies were 6.5 x 10(5) IU and 1.5 x 10(6) IU, respectively. Biologic standardization by quantitative skin testing was performed with AE (20 selected patients) and PAE (12 patients). Median Ch was calculated by linear regression analysis (log-log model). One ampoule of AE contained 65,300 BU and 1 ml (vial) of PAE contained 166,000 BU. Der p AE could serve as a croatian national standard for further production of Der p allergenic extracts.

[Evaluation of the potency of the allergen preparation Ambrosia elatior using a skin test and the inhibition radioallergosorbent test]

The total allergenicity of a pollen extract Ambrosia elatior was measured by quantitative prick test applied to the skin of seven highly sensitive patients and by standardized method of RAST-inhibition. Five 10-fold dilutions of the allergen concentration together with histamine hydrochloride 1 mg/ml (H1) were used. The induced wheal diametres for each concentration in per cent of the patient's own histamine wheal, were calculated. There was highly significant correlation (r = 0.9951) between the intensity of IgE mediated skin reactions and the IgE binding molecules in whole pollen extract. The concentration which provides the wheal equivalent to those of H1, found by linear regression analyses, was 54.9 micrograms/ml) in order to inhibit radioallergosorbent test with a pooled serum from the same patients, containing specific IgE antibodies against relevant allergens. Relevant allergen was a disk-allergen W1 (Pharmacia Diagnostics, Uppsala) The quantity of inhibition was proportional with allergen concentration (r = 0.9813). The concentration of 55.9 micrograms/ml, by linear regression analyses elicits inhibition of 50 per cent in RAST. It is concluded that quantitative prick test and histamine estimated skin sensitivity have a good clinical applicability in assessment of releaseability of skin mast cells, and together with RAST inhibition, provides the precise combined method for calibration of an allergenic extract potency.

[Procollagen type 111 peptide levels in patients with bronchial asthma and COPD]

The aim of these study was to evaluate if the inflammatory injury of parenchymal cells can lead to proliferation of fibroblasts and deposition of increased amounts of collagen, measured by the increased concentration of procollagen in blood, in patients with asthma and COPD. We evaluated 22 patients with asthma that has lasted more than 5 years, 18 patients with COPD and 20 healthy subjects. RIA-gnost method (Behring) was used to measure the procollagen peptide concentrations in blood. Our results showed that the concentration of procollagen peptide in blood samples from patients with asthma was 5.8 +/- 2.4, 4.9 +/- 1.8 in patients with COPD and 11.1 +/- 3.6 in healthy subjects. There was no significant difference between patients with asthma, COPD and healthy subjects (p less than 0.01). It can be concluded that there is no increased deposition of collagen in patients with long lasting asthma and COPD. Further studies of active collagen deposition in the early acute forms of these diseases are in progress.

Oral immunotherapy of chronic bronchitis: a double-blind placebo-controlled multicentre study

104 patients with chronic bronchitis were treated under randomized double-blind conditions with either Broncho-Vaxom (BV) or a placebo over a period of 6 consecutive months. The beneficial effect of BV was manifested by a statistically significant reduction in the duration of acute episodes and of fever (p less than 0.001) with respect to the placebo group. The consumption of antibiotics dropped significantly in the BV group (p less than 0.05) but not in the placebo group. The serum IgA levels increased in the BV group and the difference with the placebo group was statistically significant (p less than 0.05) from the 3rd month onwards. In the patients with bronchitic exacerbations during the trial, T-lymphocyte counts increased steadily under BV therapy until 3 months after the exacerbation (p less than 0.05), but not under the placebo. BV was generally well tolerated with the exception of 1 patient who reported nausea and upper abdominal pain. In their assessment of the overall therapeutic effect, the physician judged BV to be significantly superior (p less than 0.001) to the placebo as regards both the curative and prophylactic efficacy.