在美国，婴儿住院治疗最常见的原因是呼吸融合病毒，会感染几乎所有二岁的儿童。根据世界卫生组织统计，呼吸融合病毒与流行性感冒病毒每年造成世界上约二百万名婴儿死亡。
更糟糕的是，目前没有安全且有效的RSV疫苗可用于防止严重的呼吸道感染，也没有特殊的抗病毒疗法可治疗之。
RSV 通常导致只会造成类似感冒的上呼吸道感染。但是某些婴儿受到的感染会深入肺部，造成咳嗽、气喘和呼吸困难，这种临床症候群又称为细支气管炎。
科学家们认为这种疾病是由于免疫系统中的T淋巴细胞对于肺部产生过度反应，导致感染造成的最严重的症状。
但是现在，得克萨斯大学医疗Galveston分院(UTMB)及纽约州立大学研究机构的科学家，改变了这个观念。
研究人员比较了受到RSV感染和流行性感冒病毒感染的儿童之呼吸道分泌物，寻找其中的蛋白质和细胞激素 - T 细胞制造的免疫信号分子，但是并未发现RSV感染的婴儿体内T 细胞活化的证据。
他们认为，实际上是由于免疫反应不足而造成下呼吸道的严重RSV感染。这项发表于4月15 日的Journal of Infectious Diseases的研究结果，有助于研发出RSV或其它病毒性呼吸道传染的初期疗法。
(资料来源 : biocompare)
原始出处: http://news.biocompare.com/newsstory.asp?id=177478
部分英文原文：
The Journal of Infectious Diseases 2007;195:1126-1136
Severe Human Lower Respiratory Tract Illness Caused by Respiratory Syncytial Virus and Influenza Virus Is Characterized by the Absence of Pulmonary Cytotoxic Lymphocyte Responses
Timothy P. Welliver,1 Roberto P. Garofalo,2 Yashoda Hosakote,2 Karen H. Hintz,4 Luis Avendano,5 Katherine Sanchez,5 Luis Velozo,6 Hasan Jafri,3 Susana Chavez-Bueno,3 Pearay L. Ogra,4 LuAnn McKinney,1 Jennifer L. Reed,1 and Robert C. Welliver, Sr.4
1MedImmune, Inc., Gaithersburg, Maryland; 2Department of Pediatrics, University of Texas Medical Branch, Galveston, and 3University of Texas Southwestern Medical Center, Dallas; 4Department of Pediatrics, Women and Children's Hospital, State University of New York at Buffalo, Buffalo; 5Programa de Virología, Universidad de Chile, and 6Unidad de Anatomía Patológica, Hospital Roberto del Río, Santiago, Chile
(See the editorial commentary by DeVincenzo, on pages 1084–6.)
Background. Respiratory syncytial virus (RSV) and influenza virus are common causes of infantile lower respiratory tract infection (LRTI). It is widely believed that both viral replication and inappropriately enhanced immune responses contribute to disease severity. In infants, RSV LRTI is known to be more severe than influenza virus LRTI.
Methods. We compared cytokines and chemokines in secretions of infants surviving various forms of respiratory illness caused by RSV or influenza viruses, to determine which mediators were associated with more-severe illness. We analyzed lung tissue from infants with fatal cases of RSV and influenza virus LRTI to determine the types of inflammatory cells present. Autopsy tissues were studied for the lymphotoxin granzyme and the apoptosis marker caspase 3.
Results. Quantities of lymphocyte-derived cytokines were minimal in secretions from infants with RSV infection. Concentrations of most cytokines were greater in influenza virus, rather than RSV, infection. Lung tissues from infants with fatal RSV and influenza virus LRTI demonstrated an extensive presence of viral antigen and a near absence of CD8-positive lymphocytes and natural killer cells, with marked expression of markers of apoptosis.
Conclusions. Severe infantile RSV and influenza virus LRTI is characterized by inadequate (rather than excessive) adaptive immune responses, robust viral replication, and apoptotic crisis.
