The patient referred worsening of the asthma symptoms at home, especially during the evening when she returned home from work. She noticed everyday shortness of breath, wheeze and coughing while sitting in the sofa in her living room after dinner, and she needed inhaled salbutamol. Six months prior to the onset of asthma a dog was introduced at home, and at the same time the iguana terrarium that had been for 3 years in her son¡¦s bedroom, was moved to the living room and placed by the sofa. She did not refer any symptoms (cutaneous, ocular, nasal or bronchial) in contact with the dog, but when her husband cleaned the iguana¡¦s terrarium she felt chest discomfort and dyspnea. Furthermore, during a 3 days holyday away from home, without contact with her pets, she had no bronchial symptoms and did not need inhaled salbutamol.
SPT and CAP to dog were negative, as well as a specific bronchial provocation test (BPT) with dog dander extract.
No commercial iguana extracts are available for SPT, neither for serum determination of specific IgE, and it was not possible for our patient to obtain urine or scales of her iguana. However, Dr. Javier Subiza (Madrid, Spain) kindly provided us with a 10% w/v green iguana extract that elicited a positive SPT reaction at 15 minutes (7 mm mean wheal diameter) in our patient, whereas no reaction was observed in controls.
A specific BPT with the iguana extract was carried out. After the inhalation of a 1/3 dilution of the 10% w/v iguana extract the patient experienced a 21% fall in FEV1 at 15 min, that was followed by a 35% fall of PEFR at 5 hours (Figure 1).
Sputum and serum eosinophil cationic protein (ECP) determinations were performed before and after the specific BPT. Basal ECP values in serum and sputum were 40.6 and 46.8 ƒÝg/l, respectively. Twenty four hours after the iguana BPT the serum and sputum ECP values raised to 90.3 and 173 ƒÝg/l, respectively (Figure2)
We performed an SDS- PAGE IgE Immunoblotting with the iguana extract, and two IgE binding bands were identified with molecular weighs around 50 and 60 kDa (Figure 3)