EXPERIMENTAL ASTHMA DEVELOPED BY ROOM AIR CONTAMINATION WITH COCKROACH ALLERGEN

To study the asthmatogenic effect of certain airborne elements of the home environment, we studied a group of guinea pigs exposed to aerosol ized cockroach allergen (CRa) and side-stream cigarette (S-SC) smoke. Four groups of guinea pigs were exposed to aerosols, either saline or CRa, for 4 weeks, after a sham or S-SC smoke pretreatment. Anaphylacti c antibodies were measured by passive cutaneous anaphylaxis (PCA) assa y and by skin test. Animals were challenged with aerosol CRa on day 35 , and lung function and leukotrienes (LTB(4) and LTC(4)/D-4) were meas ured. Skin tests were positive on days 21 and 29. The antibodies were heat-stable, IgG1a-like antibodies (PCA titers 1:2-18). The CRa challe nge caused an immediate reduction in both the maximal expiratory flow rate at 50% of the lung capacity and respiratory compliance. The decre ased lung function continued for up to 6 h (p < 0.0001). LTB(4) and LT C(4)/D-4 were elevated (p < 0.0001) in the sensitized animals at the c orresponding times of reduced lung function. S-SC smoke did not affect the CRa sensitization; instead, a protective effect on the CRa-induce d bronchospasms was noted. Thus, the study indicates that a simple air borne CRa exposure without an adjuvant sensitizes guinea pigs, and tha t the animals respond to antigen challenge with CRa-specific airway ob structions.