Decrease of complement hemolytic activity after an allergen-house dust-bronchial provocation test

Area of Science:

• Immunology
• Pulmonology
• Allergy Research

Background:

• Bronchial asthma involves airway inflammation and hyperresponsiveness.
• House dust mite allergen is a common trigger for allergic asthma.
• Serum complement system plays a role in inflammatory and immune responses.

Purpose of the Study:

• To investigate the relationship between bronchial reactions to house dust allergen and serum complement hemolytic activity in children with asthma.
• To assess the effect of sodium cromoglycate on complement changes following allergen challenge.

Main Methods:

• Twenty-two children with asthma and positive skin tests to house dust allergen underwent bronchial provocation tests.
• Bronchial reactions (early and late) and serum complement hemolytic activity were measured at various time points post-challenge.
• The impact of sodium cromoglycate on complement activity was evaluated in a subset of patients.

Main Results:

• No consistent correlation was found between changes in serum complement hemolytic activity and either early or late bronchial reactions.
• A reproducible decrease in complement hemolytic activity was observed in eight patients after allergen challenge.
• Sodium cromoglycate administration prevented this complement drop in four out of seven patients.
• A longer duration of early bronchial obstructive reaction was noted in tests with concurrent complement changes.

Conclusions:

• Serum complement hemolytic activity changes do not reliably parallel immediate or delayed bronchial responses to house dust allergen in asthmatic children.
• The observed complement drop in some patients suggests a potential, albeit inconsistent, involvement of the complement system in allergen-induced asthma.
• Sodium cromoglycate demonstrated a capacity to inhibit allergen-induced complement activation, indicating a possible therapeutic mechanism beyond mast cell stabilization.