ROLE OF ANIMAL DANDERS AS INHALANT ALLERGENS IN BRONCHIAL-ASTHMA IN INDIA

The etiological significance of animal danders in Indian patients with nasobronchial disorders has not yet been investigated. In the present study, the role of animal danders in the etiology of bronchial asthma was studied. Extracts of danders from 6 animals along with guinea pig whole pelt were prepared. Intradermal and bronchial provocation tests with these extracts were performed on (i) 68 asthmatics and (ii) 20 n onallergic healthy volunteers. in patients, significant positive skin reactions (2+ to 4+) ranged from 1.4% each with guinea pig whole pelt and ox dander to 8.8% with dog dander extracts. None of the healthy vo lunteers elicited such a response. On bronchial provocation, 20% and 5 3.8% of the tests were positive in asthmatics showing 1+ and 2+ skin r eactivity, respectively. All the patients as well as controls elicitin g negative intradermal responses demonstrated uniformly negative bronc hial provocation tests to different dander ext,acts. Analysis of vario us clinical features of asthmatics with respect to skin positivity to dander/pelt extract was also carried out. Radioallergosorbent tests (R ASTs) were performed to estimate dander-specific IgE levels in the ser a of patients showing different grades of skin response to dander extr acts of dog, horse, and goat. Sixty percent of sera from the patients showing 2+ to 4+ skin reactivity to various animal dander extracts sho wed positive RASTs. RAST positivity as well as RAST ratio increased wi th increase in the intensity of skin response. All the patients with p ositive cutaneous as well as positive bronchial responses also showed positive RASTs. Similarly, all the patients with positive skin and pos itive RASTs showed positive bronchoprovocation tests. These results su ggested that animal danders play an important role in the etiology of bronchial asthma. Some of the clinical characteristics of asthmatics, such as (i) early age at onset of asthma, (ii) positive family history , and (iii) asthma with associated allergies, have significant bearing on the cutaneous response to various dander extracts.