[Investigation of the presence of human metapneumovirus in patients with chronic obstructive pulmonary disease and asthma and its relationship with the attacks].

Human metapneumovirus (hMPV), an enveloped RNA virus classified in Paramyxoviridae family, was first characterized in 2001 from children with acute respiratory tract infection. Recent studies have suggested hMPV to play a role in chronic obstructive pulmonary disease (COPD) and asthma attacks. The aims of this study were to investigate the frequency of hMPV in patients with COPD and asthma, its effects on the severity of the attacks and the relationship between demographical and clinical factors. A total of 123 patients, including 66 with COPD (45 were in attack and 21 were stable) and 57 with asthma (33 were in attack and 24 were under control) diagnosed according to the criteria of Global Initiative for Chronic Obstructive Lung Disease and the Global Strategy for Asthma Management and Prevention, respectively, were included in the study. Nasopharyngeal lavage samples collected from all of the patients have been evaluated for the presence of hMPV-RNA by using a reverse transcriptase-polymerase chain reaction (RT-PCR) targeting F gene region of the virus. hMPV-RNA positivity rates in patients with COPD and asthma were observed as 30.3% (20/66) and 31.6% (18/57), respectively, and the difference between the groups were not statistically significant (p= 1.00). When patients were compared according to their disease status, hMPV was detected in 31.1% (14/45) of patients with COPD attack and 28.6% of stable patients (p> 0.05). These rates were found as 36.4% (12/33) and 25% (6/24) in patients with asthma attack and controlled asthma, respectively (p> 0.05). Although the virus detection rates in patients with COPD and asthma attacks (26/78; 33.3%) were higher than the patients with stable/controlled disease (12/45; 26.7%), the difference was not found as statistically significant (p= 0.57). The detection rate of hMPV-RNA was 26.1% in patients who can be treated at home and hospital without any need of intensive care and mechanical ventilation, while this rate was 36.4% in patients with COPD attack who require intensive care and mechanical ventilation (p= 0.67). Similarly, hMPV-RNA was detected more frequently in asthma patients with moderate and severe attacks (45%) than in patients with mild attacks (23.1%); however this difference was also not statistically significant (p= 0.28). No association of hMPV-RNA detection and demographical and clinical characteristics (age, gender, medical history, smoking status, allergy, COPD severity, asthma severity, the severity of attacks, using inhaled steroid, fever) of the patients could be demonstrated (p> 0.05), except the severity of the disease in patients with asthma (p= 0.02). In conclusion, further studies with large number of cases are needed to elucidate the role of hMPV in the occurrence and severity of COPD and asthma attacks.