[Changes in lung function after a bronchial provocation test with cockroach antigens].

BACKGROUND

Cockroach allergens sensitized patients at a very young age and can predispose to severe asthma on atopic children.

OBJECTIVE

To evaluate the FEV, changes induced after bronchoprovocation with Blatella germanica (Bg) or placebo on allergic respiratory children.

MATERIAL AND

METHODS

A prospective transversal study was performed in 25 children from 8 to 16 yr with allergic rhinitis and/or asthma diagnosis with sensibility only to Bg (Bayer Corp allergens) by Prick skin test, with a 1:20 weight/volume dilution. After previous training on spirometry, they assisted for a double blind bronchial challenge with 10, 25, 50, 75, 100, 150, 200, 300, 400, 500 until 750 proteic nitrogen units of Bg or 0.9% NaCl solution in a nebulized open circuit, with a 5 litter flow for 3 min. A week after, they returned for the crossover double blind bronchial challenge. At the beginning of the study a basal spirometry was performed and subsequent spirometrics at 1.5 and 3 min after each challenge with a 10 min rest between the challenges. The test was interrupted if cough, dyspnea, wheezing and/or a 15% or more FEV1 fall appeared.

RESULTS

Twelve patients showed a FEV1 fall with the antigen challenge, all with specific lgE for Bg. All they had positive skin test to Bg, 9 had asthma and rhinitis and 3 only asthma. When placebo was used 6 patients showed a FEV1 fall. When comparing the average basal and final FEV1 values after the challenges, the fall was statistical significant in both groups with a p = 0.0015 when Bg was used, and p = 0.046 with placebo.

CONCLUSION

These results show that two times fold number of patients challenged with Bg had a FEV1 fall than placebo, and the t Student test showed that antigen challenge was more significant than placebo. We demonstrated that respiratory allergic patients sensitised with Bg after a bronchial challenge with these allergens show a FEV1 fall. This suggests that cockroach allergen sensitisation can be on account of children's asthma.