OBJECTIVE: This study was undertaken to assess the levels of the IgE cross-reactivity between Blo t 5 and Der p 5 by using sera from a large cohort of asthmatic children in subtropical and tropical countries.
METHODS: Purified recombinant Blo t 5 and Der p 5 were produced in Pichia pastoris and tested against sera from 195 asthmatic children. The IgE cross-reactivity was examined by direct, inhibitory and competitive human IgE enzyme-linked immunosorbent assay as well as skin prick tests.
RESULTS: The Blo t 5 IgE responses were 91.8% (134 of 146) and 73.5% (36 of 49) for Taiwanese and Malaysian sera, respectively. The Blo t 5 specific IgE titers were significantly higher than those of Der p 5 (P Skin prick tests performed on asthmatic children in Thailand also showed differential IgE response to Blo t 5 and Der p 5.
CONCLUSION: By using a large panel of asthmatic sera and a combination of in vitro and in vivo assays, the major allergen of B tropicalis in tropical and subtropical regions, Blo t 5, exhibits low levels of IgE cross-reactivity with homologous Der p 5. These findings suggest that highly specific clinical reagents are necessary for precise diagnosis and immunotherapeutic treatment of sensitization to group 5 mite allergens.
MATERIALS AND METHODS: In 2008, 142 newly diagnosed patients with AR were seen and underwent skin prick testing with 90 patients completing the study.
RESULTS: Intermittent mild and moderate/severe AR were evident in 10% and 21.1% of the patients, while persistent mild and moderate/severe were seen in 20% and 48.9%, respectively. Rhinitis and asthma co-morbidity occurred in 28.8% with asthma incidence significantly higher in persistent AR (P = 0.002). There was no significant association between AR severity, city living and asthma co-morbidity. Nasal itchiness and sneezing were the main presenting complaints and were more common in intermittent AR (P <0.05). Sleep disturbance was associated with moderate-severe AR (P <0.05). Polypoidal mucosa was associated with asthma co-morbidity (P <0.05). Monosensitivity reaction occurred in 12.2% of patients and was associated with fungi sensitivity (P <0.05). Majority of patients were oligosensitive (52.8%) and polysensitive (34.4%) and were significantly associated with moderate-severe persistent AR (P <0.01). The highest positive skin prick reaction and the largest average wheal diameter were for the house dust mites and cat allergen (P <0.05).
CONCLUSION: Our results reflected the AR profiles in our country, which was comparable with typical profiles of the neighbouring country and other Mediterranean countries with a similar temperate climate.