Associations between Nasal Torquetenovirus Load and Spirometric Indices in Children with Asthma

Abstract

Fifty-nine children with well-controlled, mild to moderate persistent asthma were studied for the presence and load of torquetenovirus (TTV) in nasal fluid. Rates of TTV positivity and mean nasal TTV loads were not dissimilar to those observed in the general population and in a group of 30 age- and residence-matched healthy control children without a history of asthmatic disease. However, in the children with asthma, 3 important indices of lung function--forced expiratory flow (FEF) in which 25% and 75% of forced vital capacity (FVC) is expired (FEF(25%-75%)), forced expiratory volume in 1 s/FVC, and FEF(25%-75%)/FVC--showed an inverse correlation with nasal TTV load. Furthermore, signs of reduced airflow were more frequent in the children with asthma who had high nasal TTV loads (> or =6 log(10) DNA copies/mL of nasal fluid) than they were in those who had low nasal TTV loads (<6 log(10) DNA copies/mL of nasal fluid), despite similar therapy regimens. In contrast, the control children showed no associations between nasal TTV load and the spirometric indices. Levels of eosinophil cationic protein in sputum were also greater in the children with asthma who had higher nasal viral burdens than they were in those who had lower nasal viral burdens. These findings are the first report of TTV infection status in children with asthma and suggest that TTV might be a contributing factor in the lung impairment caused by this condition.

Current and Future Prospects of Torque Teno Virus

“…Some investigators claimed that TTV has an association with progress of asthma. According to them, the Th2 signaling mechanism, which plays an important role in pathogenesis of asthma, get disturbed because of TTV replication [118]. A few studies have shown an association between Human Papiloma Virus and TTV [90].…”

Respiratory Viruses and Torque Teno Virus in Adults with Acute Respiratory Infections

“…The TTV load was associated with airflow limitation within the peripheral airways in children with bronchiectasis or asthma [36,37]. TTV may disrupt the mucociliary escalator, similar to other respiratory viruses [35]; however, its pathological mechanism remains poorly understood.…”

The Diversity of Torque Teno Viruses: In Vitro Replication Leads to the Formation of Additional Replication-Competent Subviral Molecules

“…The ubiquitous nature of TTV infections has hampered efforts to associate it with the pathogenesis of disease (9,15,25,41). A possible etiological association with diseases of the liver (reviewed in reference 36) and respiratory tract (3,30,31,49), hematopoietic malignancies (9,10,13,15,25,53,59), and autoimmune diseases (9, 26, 28, 54) have been reported.The presence of a variety of intragenomic rearranged TTV subviral molecules (TTV) in serum samples and the in vitro transcription of a subviral molecule constituting only 10% of the complete genome initiated the discussion whether TTVs may share similarities to the plantvirus family Geminiviridae (8, 23). Both mono-and bipartite geminiviruses associate with single-stranded DNA satellites to form disease-inducing complexes (16,36,46,47,52,55).…”

“…The ubiquitous nature of TTV infections has hampered efforts to associate it with the pathogenesis of disease (9,15,25,41). A possible etiological association with diseases of the liver (reviewed in reference 36) and respiratory tract (3,30,31,49), hematopoietic malignancies (9,10,13,15,25,53,59), and autoimmune diseases (9,26,28,54) have been reported.…”