High Rates of Detection of Respiratory Viruses in Tonsillar Tissues from Children with Chronic Adenotonsillar Disease

<div><p>Chronic tonsillar diseases are an important health problem, leading to large numbers of surgical procedures worldwide. Little is known about pathogenesis of these diseases. In order to investigate the role of respiratory viruses in chronic adenotonsillar diseases, we developed a cross-sectional study to determine the rates of viral detections of common respiratory viruses detected by TaqMan real time PCR (qPCR) in nasopharyngeal secretions, tonsillar tissues and peripheral blood from 121 children with chronic tonsillar diseases, without symptoms of acute respiratory infections. At least one respiratory virus was detected in 97.5% of patients. The viral co-infection rate was 69.5%. The most frequently detected viruses were human adenovirus in 47.1%, human enterovirus in 40.5%, human rhinovirus in 38%, human bocavirus in 29.8%, human metapneumovirus in 17.4% and human respiratory syncytial virus in 15.7%. Results of qPCR varied widely between sample sites: human adenovirus, human bocavirus and human enterovirus were predominantly detected in tissues, while human rhinovirus was more frequently detected in secretions. Rates of virus detection were remarkably high in tonsil tissues: over 85% in adenoids and close to 70% in palatine tonsils. In addition, overall virus detection rates were higher in more hypertrophic than in smaller adenoids (p = 0.05), and in the particular case of human enteroviruses, they were detected more frequently (p = 0.05) in larger palatine tonsils than in smaller ones. While persistence/latency of DNA viruses in tonsillar tissues has been documented, such is not the case of RNA viruses. Respiratory viruses are highly prevalent in adenoids and palatine tonsils of patients with chronic tonsillar diseases, and persistence of these viruses in tonsils may stimulate chronic inflammation and play a role in the pathogenesis of these diseases.</p> </div

Frequencies of virus co-infections in different sample sites in 121 patients with chronic adenotonsillar diseases.

<p>Frequencies of virus co-infections in different sample sites in 121 patients with chronic adenotonsillar diseases.</p

Frequencies of specific viruses and viral associations at different sample sites in 121 patients with chronic adenotonsillar diseases.

<p>One patient had co-infection with five viruses: HBoV + HRV + HEV + HRSV + HPIV; PT: palatine tonsil; Ad: adenoid tissue; NS: nasopharyngeal secretion.</p>*<p>The indicated single virus or combination was the only identified at any of the sites in the patient.</p>**<p>Adenoids were obtained only from 119 of the total of 121 patients included in this study.</p

Viral prevalence determined by qPCR in the different sample sites in 121 patients with chronic adenotonsillar disease.

*<p>Any site: results of viral detection at any of the sites analyzed.</p>*<p>Adenoids were obtained only from 119 of the total of 121 patients included in this study.</p>#<p>All viruses: positivity for at least one virus by qPCR.</p

Demographic data and virus detection frequencies in patients according to categories of adenotonsillar disease.

<p>RT: Recurrent Tonsillitis; TH: Tonsilar Hypertrophy (Brodsky grade >3); non RT/TH: patients with smaller size tonsils (less than Brodsky 3) and without recurrent tonsillitis; RT/TH: Recurrent Tonsillitis and Tonsilar Hypertrophy.</p>*<p>p≤0.05.</p

Numbers of positive samples taken from different sites in 119 patients with chronic adenotonsillar disease from whom samples were obtained from all sites.

<p>Adenoids were not available from two patients, one of whom was negative for all tested viruses, while the other had HRSV in NS.</p><p>PT: palatine tonsil; Ad: adenoid; NS: nasopharyngeal secretion.</p>*<p>Total number of positive samples.</p

Frequencies of virus detection in patients with chronic adenotonsillar diseases.

<p>(<b>A</b>) Overall frequencies of virus detection by qPCR in different sample sites of 121 patients with chronic adenotonsillar disease. (<b>B</b>) Frequencies of detection of each tested virus by qPCR at different sites in 121 patients with chronic adenotonsillar disease.</p

Demographic data and virus detection frequencies in patients according to adenoid sizes.

*<p>p≤0.05.</p><p>Obs: Adenoids were not available from two patients.</p