目的 探讨淋巴细胞各亚群及细胞免疫应答产物干扰素-γ(IFN-γ)水平在弓形虫感染患儿细胞免疫应答中的变化趋势及临床意义。方法 选取2011 年1 月至2014 年4 月检测出Tox-IgM 阳性的34 例患儿为Tox-IgM 阳性组,同时选取既往感染的TOX-IgG 阳性患儿12 例为TOX-IgG 阳性组,另选取行健康体检的健康儿童54 例为对照组。应用流式细胞仪检测各组外周血淋巴细胞CD4⁺、CD8⁺、CD19⁺ 和NK 细胞水平,并计算CD4⁺/CD8⁺ 比值;采用酶联免疫吸附试验(ELISA)检测各组患儿血清中IFN-γ 的水平。结果 Tox-IgM 阳性组患儿CD4⁺、CD4⁺/CD8⁺ 比值明显低于TOX-IgG 阳性组和对照组,CD8⁺、NK 细胞和血清IFN-γ 水平高于TOXIgG阳性组和对照组(P<0.05)。TOX-IgG 阳性组患儿血清IFN-γ 水平高于对照组(P<0.05)。Tox-IgM 阳性组患儿CD8⁺ 水平与血清IFN-γ 水平呈正相关(r=0.756,P<0.05)。结论 CD4⁺、CD8⁺ 以及NK 细胞等免疫细胞及其免疫应答产物IFN-γ 水平变化在弓形虫感染过程中发挥着重要的作用。

Objective To study the changes and significance of lymphocyte sunsets and serum interferon-γ (IFN-γ) levels in children with toxoplasma infection. Methods Thirty-four children who were newly diagnosed with toxoplasma infection (TOX-IgM⁺ group) between January 2011 and April 2014, 12 children who had ever been diagnosed with toxoplasma infection (TOX-IgG⁺ group), and 54 healthy children (control group) were enrolled. The percentages of CD4⁺, CD8⁺, CD19⁺ and NK cells in peripheral blood lymphocytes were detected by flow cytometry. Serum levels of IFN-γ were measured using ELISA. Results The percentages of CD4⁺ cells and the CD4⁺/CD8⁺ ratio in the TOX-IgM⁺ group were significantly lower than in the TOX-IgG⁺ and control groups, while the percentages of CD8⁺ and NK cells and serum IFN-γ levels were significantly higher than in the other two groups (P<0.05). The TOXIgG⁺ group had higher serum IFN-γ levels than the control group (P<0.05). There was a positive correlation between the percentage of CD8⁺ cells and serum IFN-γ levels in the TOX-IgM⁺ group (r=0.756; P<0.05). Conclusions CD4⁺, CD8⁺ and NK cells may play important roles in the resistance against toxoplasma infection by promoting the secretion of cytokines.