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Human rhinovirus (HRV) and coronavirus (HCoV) infections are associated with both upper respiratory tract illness ("the common cold") and lower respiratory tract illness (pneumonia). New species of HRVs and HCoVs have been diagnosed in the past decade. More sensitive diagnostic tests such as reverse transcription-polymerase chain reaction have expanded our understanding of the role these viruses play in both immunocompetent and immunosuppressed hosts. Recent identification of severe acute respiratory syndrome and Middle East respiratory syndrome viruses causing serious respiratory illnesses has led to renewed efforts for vaccine development. The role these viruses play in patients with chronic lung disease such as asthma makes the search for antiviral agents of increased importance., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Tobacco-related lung diseases, including chronic obstructive pulmonary disease (COPD), are major causes of lung-related disability and death worldwide. Acute exacerbation of COPD (AE-COPD) is commonly associated with upper and lower respiratory tract viral infections and can result in respiratory failure in those with advanced lung disease., Objective: We sought to determine the mechanism underlying COPD exacerbation and host response to pathogen-derived factors., Methods: Over a 24-month period, we assessed the viral causes for upper and lower respiratory tract infections in patients with COPD (n = 155) and control subjects (n = 103). We collected nasal and bronchoalveolar lavage fluid and peripheral blood under baseline and exacerbated conditions. We determined the effect of human rhinovirus (HRV) proteinases on T-cell activation in human subjects and mice., Results: HRVs are isolated from nasal and lung fluid from subjects with AE-COPD. Bronchoalveolar lavage fluid and CD4 T cells from patients with COPD exhibited a T(H)1 and T(H)2 cell cytokine phenotype during acute infection. HRV-encoded proteinase 2A activated monocyte-derived dendritic cells in vitro and induced strong T(H)1 and T(H)2 immune responses from CD4 T cells. Intranasal administration of recombinant rhinovirus proteinase 2A in mice resulted in an increase in airway hyperreactivity, lung inflammation, and IL-4 and IFN-gamma production from CD4 T cells., Conclusion: Our findings suggest that patients with severe COPD show T(H)1- and T(H)2-biased responses during AE-COPD. HRV-encoded proteinase 2A, like other microbial proteinases, could provide a T(H)1- and T(H)2-biasing adjuvant factor during upper and lower respiratory tract infection in patients with severe COPD. Alteration of the immune response to secreted viral proteinases might contribute to worsening of dyspnea and respiratory failure in patients with COPD., (Copyright (c) 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Rhinoviruses and coronaviruses cause the majority of common colds and play a part in more serious respiratory illnesses that lead to increased morbidity and mortality. Patients who are infants or elderly, have asthma or chronic obstructive pulmonary disease (COPD), or are immunosuppressed have increased frequency of rhinovirus-related respiratory complications. Newer diagnostic tests such as reverse transcriptase polymerase chain reaction (RT-PCR) have greatly expanded our understanding of the importance of these respiratory viruses. Although there are no currently approved antiviral agents for clinical use, our increased understanding of the virus-host interaction should lead to new intervention strategies.

Rhinoviruses, a genus of the family Picornaviridae, are the cause of more than 50% of respiratory tract infections. Complications of rhinovirus infections, which include otitis media, sinusitis, exacerbations of asthma, and other pulmonary diseases, can be significant in certain populations. Reverse transcriptase-polymerase chain reaction has allowed the identification of rhinoviruses and led to a greater appreciation of the role of this pathogen in upper and lower respiratory tract disease. Furthermore, antiviral agents with broad activity against rhinoviruses have recently been developed, have undergone clinical trials, but have not been approved for clinical use. By altering the clinical course of picornavirus infections, it may be possible to minimize their potential adverse consequences.

Rhinoviruses and coronaviruses cause significant morbidity in immunocompetent people of all ages and in patients with underlying chronic medical or immunosuppressed conditions. Newer diagnostic tests, such as polymerase chain reaction (PCR), have expanded our understanding of these respiratory viruses in clinical infections. These sensitive diagnostic tests have been used to describe new members of these virus families, such as human rhinovirus C (HRVC) and human coronavirus NL-63 (HCoV-NL63). The epidemiology of these newly described viruses will help us develop better intervention strategies. [ABSTRACT FROM AUTHOR]