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ABSTRACT
TorqueTenovirus (TTV), now classified in a free-standing genus
Anellovirus, is a small unenveloped virus with a single-stranded
circular DNA genome of negative polarity of approximately 3,8 kilobasi. TTV is genetically highly divergent, produces long-lasting, possibly life-long viremia in approximately 80% of apparently healthy individuals of all ages throughout the world and has, therefore, been proposed to represent a commensal human virus. Recently, it has been demonstrated that, in children under 2 years hospitalized for acute respiratory diseases (ARD), TTV loads correlated with the severity of disease and with the percentages of circulating T and B cells. These findings suggest that the virus could play a role in ARD of infants and might have immunomodulatory effects.
In this study, a group of children (8 months - 16 years aged) affected by chronic respiratory diseases (bronchiectasis and asthma) and a group of healthy children, have been investigated for TTV presence and loads. Bronchiectasis is a serious disease which affects the respiratory tract and is characterized by an irreversible, abnormal expansion of the lungs, usually accompanied or associated to chronic inflammation to various congenital and/or acquired conditions. Asthma
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is a chronic inflammatory disease which affects the respiratory tract and in which pathogenesis several types of cells (eosinophil, lymphocytes-T, etc.. ) play an important role .
The aim of the study has been to investigate the role of TTV infection in subjects affected by chronic respiratory diseases. The results have demonstrated that TTV infection is highly prevalent in the study subjects and that virus loads in blood and in nasal secretions inversely correlated with some importa nt indices of lung function both in subjects with asthma and in subjects with bronchiectasis.
Furthermore, in the last group of subjects, TTV loads were positively correlated with the disease severity as estimated by high resolution computed tomography. Although no compelling evidence has been found that TTV is the direct cause of ARD in the children studied, our findings suggest that the virus might be a contributing factor in the lung impairment caused by these clinical conditions.
