STUDY ON COCKROACH ANTIGEN AS A PROBABLE CAUSATIVE AGENT IN BRONCHIAL-ASTHMA

Bronchial provocative test (BPT) with cockroach (CR) antigen was performed in 22 asthmatic subjects. Sixteen had positive reactions (CR-positive) and 6 had negative reactions (CR-negative) to CR antigen by skin test. Imediate bronchoconstrictive response was noted following the antigen inhalation in 14 of 16 CR-positive asthamatics, while none of 6 CR-negative asthmatics showed bronchospasm. Late asthmatic responses also were noted in 13 of 16 CR-positive asthmatic individuals following BPT with CR antigen. The dual asthmatic reactions in CR-positive individuals were mostly inhibited by the prior administration of cromolyn sodium. Three-fold increases in peripheral eosinophil counts were noted 24 h following BPT with CR antigen. CR-induced asthmatic responses are apparently allergen-specific. CR probably plays a causative role in allergic asthma in the population studied.