サハラ以南アフリカ3カ国の小児におけるヒトライノウイルスの分子サブタイプ解析

Molecular Subtyping of Human Rhinovirus in Children from Three Sub-Saharan African Countries.

• Vicky L Baillie
• David P Moore
• Azwifarwi Mathunjwa
• Palesa Morailane
• Eric A F Simões
• Shabir A Madhi

抄録

重症呼吸器疾患時のヒトライノウイルス（HRV）の発症機序はいまだ不明であるため，我々は小児の重症感染と無症状感染時に得られた HRV の分子サブタイピング結果との関係を探ることを目的とした．2011 年 8 月から 2013 年 8 月までの間に，肺炎で入院した小児（1～59 ヵ月齢）および年齢頻度をマッチさせた対照群の鼻咽頭/咽頭スワブを採取した．綿棒を用いて、定量的リアルタイム PCR 法を用いて HRV を含む呼吸器病原体の検査を行いました。HRV陽性サンプルは、5'ノンコーディング領域（5'NCR）を標的とした系統解析のために配列決定されました。データによると、HRV の検出率には症例と対照群で差はありませんでした（21% 対 20%、0.693）が、生後 13～59 ヵ月の小児では、HRV の検出率は症例に関連していることが多く（21% 対 16%、0.009）、主に HRV-C に起因していました（12% 対 7%、0.001）。全体的に、HRV 種の有病率の分子サブタイピングの結果は、症例（HRV-A：48%、HRV-B：7%、HRV-C：45%）と対照群（HRV-A：45%、HRV-B：10%、HRV-C：45% [0.496]）の間で差はありませんでした。肺炎と HRV-C の患者は、HRV-A の患者よりも高齢で（12.1 ヵ月対 9.4 ヵ月、0.033）、喘鳴を伴う可能性が高かった（35% 対 25%、0.031）。このように、HRV の検出率は高く、症例と対照群では遺伝的多様性が同程度であったため、鼻咽頭検体中の HRV の存在が乳幼児の重症肺炎の発症に関与しているとの解釈は混乱をきたしました。しかし、生後 13～59 ヵ月の小児では、HRV 検出、特に HRV-C 検出は、特に喘鳴疾患を有する小児において、症例の状態と関連していた。

The pathogenesis of human rhinovirus (HRV) during severe respiratory disease remains undefined; thus, we aimed to explore the relationship between the HRV molecular subtyping results obtained during severe and asymptomatic childhood infections. Nasopharyngeal/oropharyngeal swabs from children (1 to 59 months of age) hospitalized with pneumonia and from age-frequency-matched controls were collected between August 2011 and August 2013. Swabs were tested for respiratory pathogens, including HRV, using quantitative real-time PCR assays. HRV-positive samples were sequenced for phylogenetic analysis by targeting the 5' noncoding region (5'NCR). Our data showed that there were no differences in the prevalence of HRV detection among cases and controls (21% versus 20%, 0.693); however, among children 13 to 59 months old, HRV detection was more often case associated (21% versus 16%; 0.009), with the results mainly driven by HRV-C (12% versus 7%; 0.001). Overall, there were no differences in the results of molecular subtyping of the HRV species prevalence among cases (for HRV-A, 48%; for HRV-B, 7%; for HRV-C, 45%) and controls (for HRV-A, 45%; for HRV-B, 10%; for HRV-C, 45% [0.496]). Those with pneumonia and HRV-C were older (12.1 versus 9.4 months, 0.033) and more likely to present with wheeze (35% versus 25%, 0.031) than those with HRV-A cases. Thus, the rate of HRV detection was high, with similar degrees of genetic diversity among cases and controls, confounding the interpretation of the presence of HRV in nasopharyngeal samples for attribution of a causal role in the pathogenesis of severe pneumonia in infants. However, among children 13 to 59 months of age, HRV detection, in particular, HRV-C detection, was associated with case status, especially among children with wheezing disease.

Copyright © 2019 Baillie et al.