在美國(guó),，嬰兒住院治療最常見(jiàn)的原因是呼吸融合病毒,，會(huì)感染幾乎所有二歲的兒童。根據(jù)世界衛(wèi)生組織統(tǒng)計(jì),，呼吸融合病毒與流行性感冒病毒每年造成世界上約二百萬(wàn)名嬰兒死亡,。
更糟糕的是，目前沒(méi)有安全且有效的RSV疫苗可用于防止嚴(yán)重的呼吸道感染,，也沒(méi)有特殊的抗病毒療法可治療之,。
RSV 通常導(dǎo)致只會(huì)造成類(lèi)似感冒的上呼吸道感染。但是某些嬰兒受到的感染會(huì)深入肺部,，造成咳嗽,、氣喘和呼吸困難，這種臨床癥候群又稱(chēng)為細(xì)支氣管炎,。
科學(xué)家們認(rèn)為這種疾病是由于免疫系統(tǒng)中的T淋巴細(xì)胞對(duì)于肺部產(chǎn)生過(guò)度反應(yīng),，導(dǎo)致感染造成的最嚴(yán)重的癥狀。
但是現(xiàn)在,，得克薩斯大學(xué)醫(yī)療Galveston分院(UTMB)及紐約州立大學(xué)研究機(jī)構(gòu)的科學(xué)家,，改變了這個(gè)觀念。
研究人員比較了受到RSV感染和流行性感冒病毒感染的兒童之呼吸道分泌物,，尋找其中的蛋白質(zhì)和細(xì)胞激素 - T 細(xì)胞制造的免疫信號(hào)分子,，但是并未發(fā)現(xiàn)RSV感染的嬰兒體內(nèi)T 細(xì)胞活化的證據(jù)。
他們認(rèn)為,，實(shí)際上是由于免疫反應(yīng)不足而造成下呼吸道的嚴(yán)重RSV感染,。這項(xiàng)發(fā)表于4月15 日的Journal of Infectious Diseases的研究結(jié)果，有助于研發(fā)出RSV或其它病毒性呼吸道傳染的初期療法,。
(資料來(lái)源 : biocompare)
原始出處: 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.
