Andre Cartier

Allergen-induced increase in bronchial responsiveness to histamine: relationship to the late asthmatic response and change in airway caliber☆

Abstract Allergen-induced late asthmatic responses are associated with an increase in bronchial responsiveness to histamine. We have examined the relationship between the magnitude of the late asthmatic response and the magnitude and duration of increased histamine responsiveness. Allergen inhalation tests were carried out in 12 asthmatic subjects to induce a mild early asthmatic response (16% to 40% reduction in FEV 1 in the first hour after allergen inhalation); the response was followed over 8 hr to identify the occurrence and magnitude of any late asthmatic response (maximum fall in FEV 1 from baseline between 3 and 8 hr). The provocation concentration of histamine causing a decrease in FEV 1 of 20% (PC 20 ) was measured before and after inhalation of allergen. The magnitude of decrease in PC 20 correlated with the magnitude of the late asthmatic response as measured by the percent fall in FEV 1 (r = 0.8, p 20 was from 2 to 74 days and this also correlated with the magnitude of the late response (r = 0.53, p 1 , maximal expiratory flow-volume curves (on air and He-O 2 ), and histamine responsiveness were also measured before and at intervals after allergen inhalation. Four of seven subjects still had a reduction in PC 20 when the TLC, RV, FEV 1 , maximal expiratory flow-volume rates on air (V 50 air) and He-O 2 (V 50 He-O 2 ) (measured at an absolute volume corresponding plus 50% of control vital capacity) and ratio of V 50 He-O 2 to V 50 air were back t preallergen inhalation levels. In two of these subjects volume of isoflow was also back to ±10% of preallergen inhalation levels when the PC 20 was still significantly reduced. The results suggest that allergen-induced late asthmatic responses can be associated with an increase in bronchial responsiveness to histamine by mechanisms other than a reduction in baseline airway caliber alone.

Asthma and increases in nonallergic bronchial responsiveness from seasonal pollen exposure

Serial measurements of symptoms, peak flow rates, methacholine bronchial responsiveness, and ragweed-specific IgE antibodies were made before and during the ragweed pollen season in 13 sensitized subjects. Allergen inhalation tests were carried out with aerosols of pollen extract out of season in nine subjects; isolated early asthmatic responses were provoked in four, and dual responses (early followed by late) were provoked in five. During the pollen season all subjects developed hay fever and eight had symptoms of asthma. There was a real increase in methacholine responsiveness during the ragweed season. This increase appeared before or after the occurrence of asthma symptoms and changes in flow rates and was greater in subjects with symptoms in the pollen season, dual responses after allergen inhalation tests, and higher levels of ragweed-specific IgE antibodies. The results confirm the occurrence of seasonal asthma and increases in nonallergic (nonspecific) bronchial responsiveness to methacholine from seasonal pollen exposure. They suggest that the occurrence of symptoms is closely linked to the allergic inflammatory reaction and the induction of increased nonallergic responsiveness.

Occupational asthma caused by nickel sulfate

A 28-yr-old man developed asthma shortly after being exposed to nickel sulfate (NiSO4) in a metal-plating factory. Recordings of peak expiratory flow rates at work and for an off-work period showed increased variations at work, with best values on weekends. Allergy prick skin tests elicited an immediate reaction with NiSO4 at a concentration of 10 mg/ml. Experimental inhalation challenges with NiSO4 at the same concentration of 10 mg/ml for 60 sec produced a bronchial obstruction typical of an early asthmatic response. A control asthmatic subject with a similar level of sensitivity to histamine failed to react after the same inhalation of NiSO4, which suggests a specific rather than irritant mechanism for the reaction. the patient had evidence of IgE antibody to a NiSO4-human serum albumin antigen. His serum selectively bound 63 Ni, and the test was selectively blocked by nonlabeled nickel sulfate. These results, evaluated together, suggest the development of occupational asthma caused by allergy to NiSO4 in this patient.

Occupational asthma due to pepsin

A 30-year-old atopic worker exposed to pepsin powder, herb, and pollen extracts at work developed an increase in asthmatic symptoms. Monitoring of peak expiratory flow rate revealed more important fluctuations at work. Skin prick tests yielded a large immediate reaction to pepsin. Specific inhalation challenges confirmed the diagnosis; an intense early response was documented after exposure to pepsin. The pepsin IgE RAST was positive and selectively inhibited by pepsin.

Occupational asthma from reactivity to an alkaline hydrolysis derivative of gluten

A 29-year-old female subject had been working for 13 years in a company producing biscuits. She was exposed intermittently to an alkaline hydrolysis wheat gluten derivative (AHGD) that was incorporated into marshmallows. Five years before being referred, she started reporting rhinoconjunctivitis and asthmatic symptoms immediately after handling AHGD. When she was first assessed, she had avoided contact with AHGD for 1 year, and she was asymptomatic. Normal spirometry and bronchial responsiveness to histamine (provocative concentration causing a 20% fall in FEV1, 22 mg/ml) were obtained. There was a positive allergy skin test to ragweed pollen and to AHGD at 0.01 mg/ml. Skin tests with individual extracts of cereals, including wheat, were negative. Inhalation challenge with AHGD for 15 seconds caused immediate rhinoconjunctivitis and bronchoconstriction (maximum fall of 40% in FEV1 30 minutes after the exposure) with complete recovery 2 hours later. There was no reaction thereafter, and the provocative concentration of histamine causing a 20% fall in FEV1 was not significantly changed (13.1 mg/ml) 9 hours after the challenge. Inhalation challenge with wheat flour containing native gluten for 30 minutes did not cause any symptoms or significant change in FEV1. IgE RAST counts were greater with the AHGD than with gluten and the whole wheat extract; the opposite was generally found with sera from individuals with bakers asthma and wheat food allergy. With the serum of the affected worker, AHGD completely inhibited the corresponding RAST, but gluten did not. With wheat food allergy, AHGD was relatively inactive inhibition of the wheat and gluten RAST, but gluten was effective.(ABSTRACT TRUNCATED AT 250 WORDS)