Mechanisms of viral impact on asthma exacerbations

Khaitov, M. R.; Trofimov, D. U.; Petrova, T. V.; Yakovleva, K. P.; Boldyreva, M. N.; Yartsev, M. N.; Ilina, N. I.; DuBuske, L. M.; Alexeev, L. P.

Abstract Rationale Respiratory viruses are a frequent cause of wheezing in infants and children. 60 - 85% of asthma exacerbations in children and up to 50% of asthma exacerbations in adults are attributed to respiratory viruses. Previous studies investigated the role of rhinoviruses, RS-viruses and adenoviruses in development of asthma exacerbations in children hospitalized in the clinic of the Institute of Immunology (Moscow, Russia). Rhinovirus was the most frequently detected – 33 samples (24.8% of all tested samples), adenovirus – 5 samples (3.8%), RSV– 4 samples (3.0%), and mixed infections (rhinovirus and RSV) – 1 sample (0.7%). Among positive samples rhinovirus accounted for 76.7%, adenovirus - 11.6%, RSV - 9.3%, and mixed infection - 2.3%. Methods Primers for PCR diagnostics of Parainfluenza viruses of 1, 2 and 3 type and coronaviruses OC43 and 229E were developed. Investigation of HLA-alleles and genotypes was conducted in patients with virus-induced bronchial asthma to reveal HLA-associated markers of susceptibility to viral-induced asthma. Results An increased frequency of HLA-DRB1∗13 specificity and reduced frequencies of HLA-DRB1∗04 and HLA-DRB1∗11 specificities were noted in the viral-induced asthmatics compared to the healthy control group. A minimal increase of HLA-DRB1 homozygotes - 21% was also noted in comparison with the control group - 14%. Conclusions Investigation of HLA-haplotype in patients with viral-induced outbreaks of asthma via HLA-genotyping may reveal more evident associations between HLA-haplotypes and individual respiratory viral infections.