Hoekstra M O, Berends C, Dijkhuizen B, Gerritsen J, Kaufman H F
Beatrix Paediatric Clinic, Department of Paediatric Pulmonology, University Hospital of Groningen, The Netherlands.
Clin Exp Allergy. 1994 Oct;24(10):969-75. doi: 10.1111/j.1365-2222.1994.tb02730.x.
Considerable differences in the percentage of hypodense eosinophils in the peripheral blood of asthmatics have been reported by different investigators. In these previous studies dextran sedimentation was used for removal of erythrocytes prior to density centrifugation. We hypothesized that the sedimentation procedure might induce the presence of hypodense eosinophils in the peripheral blood of asthmatic patients. In order to test this hypothesis, we compared eosinophil density profiles from peripheral blood of children with asthma and of age-matched healthy controls, using different procedures. In the first method (direct method) blood samples were directly layered on a discontinuous Percoll gradient. Erythrocytes were removed by isotonic lysis. In the second method (dextran sedimentation) erythrocytes were removed by sedimentation with dextran prior to gradient centrifugation. Results of the direct method show no significant difference in percentage of hypodense eosinophils between children with asthma and healthy controls (9.19% and 6.84% respectively). However, after dextran sedimentation, children with asthma had a significantly higher percentage of hypodense eosinophils than healthy controls (15.40% and 8.84% respectively; P < 0.05). The percentage of hypodense eosinophils was correlated with the number of eosinophils and with the lung function, measured as the Tiffeneau index (FEV1/VC), in the whole group of subjects when the direct method was used. We conclude that an increased percentage of hypodense eosinophils is not present in the circulation of children with asthma, but can be induced in vitro by dextran sedimentation. Therefore, in vitro generation of hypodense eosinophils in the blood of patients with asthma seems to be related with the primed state of eosinophils.
不同研究者报告了哮喘患者外周血中低密度嗜酸性粒细胞百分比存在显著差异。在这些先前的研究中，葡聚糖沉降法用于在密度离心前去除红细胞。我们推测沉降过程可能会导致哮喘患者外周血中出现低密度嗜酸性粒细胞。为了验证这一假设，我们使用不同方法比较了哮喘儿童和年龄匹配的健康对照外周血中的嗜酸性粒细胞密度分布。在第一种方法（直接法）中，血样直接铺在不连续的Percoll梯度上。通过等渗裂解去除红细胞。在第二种方法（葡聚糖沉降法）中，在梯度离心前通过葡聚糖沉降去除红细胞。直接法的结果显示，哮喘儿童和健康对照之间低密度嗜酸性粒细胞的百分比没有显著差异（分别为9.19%和6.84%）。然而，经过葡聚糖沉降后，哮喘儿童的低密度嗜酸性粒细胞百分比显著高于健康对照（分别为15.40%和8.84%；P<0.05）。当使用直接法时，在整个受试者组中，低密度嗜酸性粒细胞的百分比与嗜酸性粒细胞数量以及以蒂夫诺指数（FEV1/VC）衡量的肺功能相关。我们得出结论，哮喘儿童的循环系统中不存在低密度嗜酸性粒细胞百分比增加的情况，但葡聚糖沉降可在体外诱导这种情况。因此，哮喘患者血液中低密度嗜酸性粒细胞的体外产生似乎与嗜酸性粒细胞的预激活状态有关。
