Article in Japanese

Evaluation of the loop-mediated isothermal amplification assay for rapid diagnosis of mumps in pediatric patients

Kensei GOTOH¹⁾, Naoko NISHIMURA¹⁾, Hiroki TAKAO¹⁾, Yuto FUKUDA¹⁾, Ayami YOSHIKANE¹⁾, Syuta KITO¹⁾, Kazunori HARUTA¹⁾, Makoto YAMAGUCHI¹⁾, Tomoyasu NOGUCHI¹⁾, Koji TAKEMOTO¹⁾, Tetsuo NAKAYAMA²⁾, Takao OZAKI¹⁾

This study prospectively evaluated the efficacy of the reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay to diagnose mumps rapidly in a clinical setting.
Fifty-one children, who enrolled in this study, presented with salivary gland swelling at this hospital between September 2013 and August 2014. Salivary swabs were obtained during the acute phase (mean ± SD, 2.4 ± 1.4 days) to test for mumps using the RT-LAMP assay, nested RT-PCR assay, and virus isolation. In addition, serum samples were collected for detecting IgG and IgM mumps antibodies by the enzyme immunoassay. Laboratory confirmation of mumps was defined as at least one of the following: 1) mumps virus isolation, 2) detection of mumps virus RNA using RT-LAMP or RT-PCR assays, or 3) detection of IgM mumps antibodies.
Of the patients with clinically diagnosed mumps, 23 (45%) had laboratory-confirmed mumps. Among these, 22 (96%) were RT-PCR positive, 20 (87%) RT-LAMP positive, 18 (78%) IgM positive, and 14 (61%) isolation positive. The concordance rate between the RT-LAMP assay and isolation, RT-PCR assay, and IgM level was 74% (17/23), 83% (19/23), and 83% (19/23), respectively. Three patients (13%), who were IgM negative, developed mumps after vaccination, which correlated with a previous study that proved IgM detection as an unreliable marker in vaccinated persons. Thus, the RT-LAMP assay will be more beneficial when the future vaccination rate increases. Therefore, we concluded that the clinical diagnosis of mumps is unreliable, and the RT-LAMP assay is noninvasive, and useful for a rapid and accurate diagnosis of mumps.

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1) Department of Pediatrics, Konan Kosei Hospital
2) Laboratory of Viral Infection, Kitasato Institute for Life Sciences

Key words	mumps, salivary gland swelling, rapid diagnosis, laboratory diagnosis, loop-mediated isothermal amplification (LAMP)
Received	June 4, 2018
Accepted	December 4, 2018

31 (1)：27─32,2019