Halminen M, Ilonen J, Julkunen I, Ruuskanen O, Simell O, Mäkelä M J
Turku Immunology Centre and Department of Virology, University of Turku, Finland.
Pediatr Res. 1997 May;41(5):647-50. doi: 10.1203/00006450-199705000-00008.
Interferons (IFNs), which are induced by viruses, form an essential part of host's defense systems against viral infections. The antiviral actions of IFNs are mediated by several IFN-inducible gene products, one of which is Mx protein. To evaluate whether MxA protein expression in lymphocytes could function as an indicator of endogenous IFN production in children with acute febrile illness, we analyzed MxA protein levels in peripheral blood lymphocytes by flow cytometry in the acute phase of the disease. Children with a laboratory-confirmed viral infection [respiratory syncytial virus (RSV) in 21, adenovirus in 10, rotavirus in 5, and influenza, herpes simplex, or EBV in 7 other cases] had significantly higher (p < 0.002) MxA protein levels (median fluorescences in different virus groups ranged from 707 to 765) compared with children with a bacterial infection (n = 12, median fluorescence 548). To characterize further MxA protein expression during infections, cells from 41 patients were stimulated in vitro with exogenous IFN-alpha, and the level of MxA protein expression was determined. The rise in MxA staining levels was significantly higher in the group with bacterial infections compared with those with viral infection (p < 0.005), further indicating that the MxA protein levels were already elevated in vivo in patients with viral infections. This study suggests that elevated MxA protein expression levels can be used in the differential diagnosis of bacterial versus viral disease in febrile children.
干扰素（IFNs）由病毒诱导产生，是宿主抗病毒感染防御系统的重要组成部分。IFNs的抗病毒作用由多种IFN诱导基因产物介导，其中之一是Mx蛋白。为了评估淋巴细胞中MxA蛋白的表达是否可作为急性发热性疾病患儿内源性IFN产生的指标，我们在疾病急性期通过流式细胞术分析了外周血淋巴细胞中MxA蛋白的水平。实验室确诊为病毒感染的患儿（呼吸道合胞病毒感染21例、腺病毒感染10例、轮状病毒感染5例，其他7例为流感病毒、单纯疱疹病毒或EB病毒感染）的MxA蛋白水平显著更高（p < 0.002）（不同病毒组的中位荧光强度范围为707至765），而细菌感染患儿（n = 12，中位荧光强度548）则不然。为了进一步表征感染期间MxA蛋白的表达情况，对41例患者的细胞进行了体外α干扰素刺激，并测定了MxA蛋白的表达水平。与病毒感染组相比，细菌感染组MxA染色水平的升高显著更高（p < 0.005），这进一步表明病毒感染患者体内的MxA蛋白水平已经升高。本研究表明，MxA蛋白表达水平升高可用于发热儿童细菌与病毒疾病的鉴别诊断。
