Natural and experimental XXXX of the lower respiratory tract.

@entity1 @entity565 @entity1097 @entity281 @entity1729 @entity1576 @entity687
Rhinoviruses are the cause of the majority of common colds, but their role in lower @entity1576 is less clear. Recent studies using the polymerase chain reaction to detect rhinoviruses have established @entity1729 as major factors in the induction of acute exacerbations of @entity565 in both adults and @entity1 , both in mild exacerbations and in more severe exacerbations leading to hospital admission. Rhinoviruses were the major virus type detected in these studies, accounting for two-thirds of viruses detected. It is not known whether rhinoviruses produce their effects by directly invading the lower airway or by indirect means. Previous clinical studies provide some evidence that rhinoviruses are capable of infecting the lower airway. However, the immunologic response, both in the upper and lower airways, remains poorly defined. Recent studies have provided evidence of increased cellular activation in peripheral blood and in bronchial biopsies in @entity1097 subjects compared with normal subjects during experimental @entity281 . The reasons for these different cellular responses are unclear. Rhinoviruses as well as other respiratory viruses have been shown to increase levels of a variety of cytokines from respiratory epithelium, monocytes, or macrophages. Prominent among these cytokines is @entity687 . We have detected increased levels of @entity687 in nasal secretions from subjects with wild-type @entity281 . We studied the mechanisms of rhinovirus-induced @entity687 production and and found protein release from both pulmonary epithelial and peripheral blood mononuclear cells. This protein production was accompanied by increased mRNA expression and evidence of infection of both pulmonary epithelial and monocyte cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)
