Detection of the Epstein–Barr virus, Human Bocavirus and novel KI and KU polyomaviruses in adenotonsillar tissues
Introduction
The palatine tonsils (tonsils) and pharyngeal tonsils (adenoids) are the most important structures in the Waldeyer's ring. Recurrent and chronic diseases of tonsils and adenoids are highly frequent in children and lead to chronic activation of the immune response, resulting in hypertrophy of the adenoidal and tonsillar lymphoid tissues [1]. These reactions can adversely affect a child, especially when there is hypertrophy and/or recurrent infection. This hypertrophy may lead to several other diseases and symptoms such as hyponasality, snoring, obstructive sleep apnea syndrome, acute otitis media, otitis media with effusion, middle ear atelectasis, cholesteatoma formation, slow feeding, acute sinusitis, abnormal facial development and behavioral problems when hypertrophy causes airway obstruction [2], [3], [4]. For these reasons, tonsillectomy with or without adenoidectomy is the most frequent surgical procedure performed by otorhinolaryngologists [5].
Yet, the etiologies of chronic adenotonsillar diseases are largely unknown. Generally, bacteria are considered to be the most likely causative agents in adenotonsillar diseases [6], [1].
However, many viruses are detected in tonsillar and adenoid tissues recently [1]. Despite these findings, systematic studies of viruses in adenoids and tonsils have been rare, especially in recurrent and/or hypertrophic adenotonsillar diseases.
In the present study, DNA expressions of Human Bocavirus (HBoV), Epstein–Barr virus (EBV) and polyomaviruses KI and WU (KIPyV and WUPyV) were investigated in children with tonsillar and adenoidal diseases using real-time polymerase chain reaction (RT-PCR). The relationships of expressions of these viruses with other clinical characteristics of children, such as patient age, gender, recurrent infection and airway obstruction were also analyzed. Seasonal variations in rates of detection of these viruses in adenoid and tonsil tissues during the absence of acute infection symptoms were also investigated. The results of this study provide a new insight about the roles of these viruses in the pathogenesis of recurrent tonsillitis and tonsillar/adenoidal hypertrophy.
Section snippets
Patients and specimen collections
This cross-sectional study was carried out from October 2012 to August 2014. A total of 51 children (31 boys and 20 girls) aged 2 to 15 (mean 6.18 ± 2.83) years were enrolled in the study. All children had adenoidal hypertrophy and tonsillar hypertrophy/or recurrent tonsillitis with indications for adenotonsillectomy. Exclusion criteria were: acute respiratory infection at the time of surgery, antibiotic treatment within 4 weeks prior to surgery, immunological disorders, and chronic medical
Viral detection
A total of 51 adenoid samples and 51 tonsil samples were tested to determine the sensitivity of the RT-PCR assays. The demographic characteristics of the patients were shown in Table 1. Considering adenoid specimens, EBV was found positive in 41.2%, Bocavirus in 43.1%, WUPyV in 7.8% and KIPyV was positive in none. While the incidence rates were statistically similar for EBV and HBoV in adenoid samples (p = 0.841), WUPyV was found to be positive significantly less frequently than EBV and Bocavirus
Discussion
In various studies, EBV has been identified as one of the most frequently met viral agents which cause recurrent tonsillitis [7], [8], [9], [10]. Tonsils are also suggested to be the onset and replication site for the infections [8]. In our study, we found out that EBV was positive most frequently in tonsillar samples of children with recurrent tonsillitis (53.8%) using real-time PCR. This was followed by samples of children with adenoid hypertrophy (41.2%) and tonsillar hypertrophy (32.0%).
Conflict of interest statement
The authors have no conflicts of interest to disclose and have no financial disclosures to make.
Acknowledgment
The authors thank ADÜ-BAP (Adnan Menderes Üniversitesi Bilimse Araştırma Projeleri) for financial support.
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