Cockroach is the second most common allergen among Hongkongers suffering from allergic diseases such as asthma, allergic rhinitis, and eczema, second only to dust mites. An international study led by The Chinese University of Hong Kong (CUHK) ‘s Faculty of Medicine (CU Medicine) has unraveled the world’s most comprehensive genome profile for the American cockroach (Periplaneta Americana), the most common in Hong Kong and identifies seven novel cockroach allergens. The study will help design effective immunotherapy for cockroach allergy.
CUHK’s CU Medicine led the study in collaboration with universities in Shenzhen and Thailand. According to CUHK, among these allergic individuals, cockroaches account for 45 percent of the sensitization rate and are one of the most common triggers, second to dust mites. Cockroaches are also responsible for a higher risk of developing asthma and for higher morbidity in asthmatics.
“Although the awareness of the negative impact of cockroach allergy has increased in the last two decades, advances in its diagnosis and treatment are slow owing to the lack of a complete cockroach allergen profile,” remarked Professor Leung Ting-fan, a Professor in the Department of Paediatrics at CU Medicine.
Regarding treating cockroach allergy, minimizing cockroach exposure remains the key approach. Many cockroach-allergic patients exhibit complex sensitization patterns to multiple cockroach-associated proteins. Due to inadequate knowledge about the full spectrum of cockroach allergens, it is currently difficult to determine the immunodominant cockroach allergen(s) and produce standardized and potent cockroach allergen extracts for optimal biotherapy treatment.
The research group led by Professor Stephen Tsui Kwok-wing, a Professor in the School of Biomedical Sciences at CU Medicine, has been working on the genomics of allergen sources for over a decade. He has collaborated with Professor Anchalee Tungtrongchitr, an international expert on cockroach allergy from Thailand’s Mahidol University, on cockroach genomics and allergy since 2018.
Dr. Xiong Qing, a Postdoctoral Fellow in the School of Biomedical Sciences at CU Medicine, said that in the study, they assembled a high-quality, chromosome-level genome with 25 chromosomes in the American cockroach. Based on their research expertise in genomics and allergy, they identified seven more novel allergens on top of the existing 13.
Tsui added that their genomic results revealed a wide range of gene family variations, such as an important detoxification gene family, glutathione S-transferase, which is highly expanded in the American cockroach genome and explains the high viability of cockroaches. Moreover, their comparative genomic analysis raised the possibility that termites may contain highly identical allergens that are cross-reactive with those of cockroaches.
Moreover, the study recommends combining the newly identified allergens with current cockroach extracts. This will facilitate the standardization of cockroach allergen extracts and benefit-risk stratification and thus improve specialist management for individuals who exhibit complex sensitization patterns.
The study results have been published in the international scientific journal “Allergy.”