偏肺病毒毛细支气管炎的临床研究

Clinical characteristics of bronchiolitis caused by human metapneumovirus in infants

目的 了解人类偏肺病毒 (hMPV)感染情况及所致毛细支气管炎的临床特征。方法 (1)采用RT PCR方法 ,对 12 6例毛细支气管炎中经呼吸道常见病原检测阴性的 5 4份鼻咽洗液标本进行hMPV基因检测 (扩增 +测序 ) ;(2 )分析hMPV感染患儿的临床资料。结果 (1)共检测出 2 1份阳性hMPV扩增产物 ,阳性率为 16 7% ,占 5 4例呼吸道常见病原检测阴性患儿的 39%。 (2 ) 2 1例hMPV毛细支气管炎中幼婴 (1～ 6月龄 )占 6 2 % ;多为低 中度发热 (86 % ) ;外周血WBC <10 0× 10 9/L者占81% ;胸部X线表现为两肺野点片状影和 (或 )肺气肿影者分别为 6 8%和 6 2 %。经临床Lowell评分 5例评为重症。hMPV毛细支气管炎患儿组主要临床特征与A亚型呼吸道合胞病毒 (hRSV)毛细支气管炎组无区别 ,仅病程较B亚型hRSV毛细支气管炎组长 (P <0 0 1)。结论 (1) 12 6例毛细支气管炎住院患儿中有 16 7%是由hMPV感染引起。 (2 )hMPV毛细支气管炎的主要临床特征与hRSV毛细支气管炎无明显差异。

Objective The fact that the acute lower respiratory infections (ALRI) are associated with a newly discovered virus, human metapneumovirus (hMPV), has been shown in several studies. The authors conducted this study to understand the etiological and clinical characteristics of bronchiolitis, one of the most common ALRI in infants, caused by hMPV. Methods Nasopharyngeal aspirate specimens from 54 out of 126 infants with bronchiolitis admitted to the Children′s Hospital Affiliated to Capital Institute of Pediatrics, Beijing from November 2002 to February 2003 were examined for hMPV gene fragments by reverse transcription-polymerase chain reaction (RT-PCR). Prior to the detection, the specimens were confirmed as negative for the common respiratory pathogens including RSV, influenza A and B, parainfluenza Ⅰ, Ⅱ, Ⅲ, adenovirus, Mycoplasma pneumoniae by indirect immunnofluorescence test, virus isolation and ELISA test. The clinical data of the patients diagnosed etiologically as hMPV infection analyzed included the infants′ age, sex, the degree of fever, the severity of wheezing and clinical Lowell score, the findings of chest examination and chest X-ray, the white blood cell count and blood gas analysis, the course of the disease, the major treatments and the outcome of the disease. Results Twenty-one specimens showed the predicted 213 bp PCR products in agarose gel and the positive rate was 16.7% of all patients (21/126) and 39% of the patients with negative results for common respiratory pathogens detections (21/54). The range of patients′ age was 2-15 months and the young infants with hMPV bronchiolitis (1-6 month of age ) accounted for 62% and the male:female ratio was 3.2∶1. The patients presented a low-medium grade fever (T<39℃) accounted for 86%; 81.0% of patients had a white blood cell count lower than 10.0×10 9/L. The radiological findings were patchey opacity in both lungs (68%) and (or) hyperinflation (62%). Assessed by the Lowell score system, 5 out of 21 cases were considered as severe cases. The major clinical findings of hMPV bronchiolitis had no significant difference compared with that of subgroup A hRSV bronchiolitis, and showed longer course of disease than that of subgroup B hRSV bronchiolitis (P<0.01). Conclusions Of the infants with bronchiolitis hospitalized in our hospital from November of 2002 through February of 2003, 16.7% were caused by hMPV infection. These data showed that the major clinical characteristics and the outcome of treatment of hMPV bronchiolitis had no statistically significant difference compared to the cases with either subgroup A or subgroup B hRSV infection.