Molecular diagnosis of human metapneumovirus

Abstract

Abstract Background The recent discovery of human metapneumovirus (hMPV) as a major respiratory pathogen has been made possible by means of reverse transcriptase-PCR (RT-PCR). Studies published so far have been mostly conducted using the molecular approach. Objective The objective of the present study was to clarify the epidemiological and clinical features of hMPV using molecular biological techniques for its diagnosis. Patients and methods A total of 189 patients with suspected viral respiratory tract infections were included and their respiratory specimens were analyzed for the presence of hMPV using a Seeplex respiratory virus detection kit. Detection techniques that were applied included virus identification by transcriptase-PCR (TC-PCR), direct fluorescent antibody staining, and the rapid culture technique known as shell vial amplification using monoclonal antibodies (mAbs) of nasal wash or aspirate fluid. The epidemiological and clinical data were analyzed and the latter were represented as percentages where applicable. Results The study determined the presence of respiratory viruses in 61 (32.3%) of the 189 respiratory samples and showed the presence of hMPV in eight (13.1%) of the 61 samples. hMPV showed variable seasonal activity. Six patients (75%) positive for hMPV had pre-existing serious disorders. Using the shell vial cultures with mAbs, we found that non-Hodgkin lymphoma patients with the related isolated virus showed a plaque of infected cells with small syncytial formations, whereas the other seven patients showed single infected cells. The RT-PCR results of all samples from hMPV-positive patients were correlated with the results of direct fluorescent antibody staining or shell vial cultures using mAbs. Conclusion hMPV is a significant pathogen in immunocompromised patients with a risk for high morbidity and mortality. A combination of diagnostic workups may be useful for confirming the detection of hMPV.