Supplementary Material for: Atopic Patients Show Increased Interleukin 4 Plasma Levels but the Degree of Elevation Is Not Sufficient to Upregulate Interleukin-4-Sensitive Genes

<b><i>Background:</i></b> Atopic diseases constitute a major health challenge for industrialized countries, and elevated levels of interleukin 4 (IL-4) frequently characterize these disorders. Previous in vitro<i></i>analyses have indicated that IL-4 strongly upregulates the expression of IL-4-sensitive genes in human monocytes. <b><i>Objective:</i></b> To explore whether similar expression alterations may contribute to the pathomechanisms of atopic diseases in vivo we carried out a small-scale case-control clinical study (<i>n</i> = 43), in which we quantified the plasma levels of IgE and IL-4 as well as the expression of selected IL-4-sensitive genes in blood leukocytes. <b><i>Methods:</i></b> 34 allergic patients suffering from allergic rhinitis (<i>n</i> = 11), atopic eczema (<i>n</i> = 11) and allergic asthma (<i>n</i> = 12) as well as 9 healthy control individuals were recruited. IgE and IL-4 plasma levels were determined by ELISA, and the expression of selected IL-4-sensitive gene products in blood leukocytes was quantified by qRT-PCR. In addition, the fatty acid oxygenase activity of isolated monocytes was measured by RP-HPLC analysis of the arachidonic acid oxygenation products (ex vivo activity assays). <b><i>Results:</i></b> We found that plasma levels of IgE and IL-4 were significantly elevated in atopic patients but the degree of elevation was not sufficient to upregulate the expression of the selected IL-4-sensitive genes in circulating leukocytes. Moreover, the arachidonic acid oxygenase activity of blood monocytes was not significantly altered in atopic patients. <b><i>Conclusion:</i></b> Our data suggest that the IL-4 plasma levels of atopic patients are not high enough to impact the expression of IL-4-sensitive genes.

**背景：** 特应性疾病是工业化国家面临的主要健康挑战，白细胞介素4（interleukin 4, IL-4）水平升高常为这类疾病的典型特征。既往体外分析显示，IL-4可显著上调人单核细胞中IL-4敏感基因的表达。
**目的：** 为探究此类表达改变是否同样参与特应性疾病的体内发病机制，我们开展了一项小型病例对照临床研究（样本量*n* = 43），对血浆免疫球蛋白E（IgE）与IL-4水平进行定量检测，并分析血液白细胞中选定的IL-4敏感基因的表达情况。
**方法：** 共招募34例过敏性疾病患者，包括变应性鼻炎（*n* = 11）、特应性皮炎（*n* = 11）及过敏性哮喘（*n* = 12）患者，同时纳入9名健康对照个体。采用酶联免疫吸附试验（ELISA）检测血浆IgE与IL-4水平，通过实时荧光定量聚合酶链反应（qRT-PCR）定量检测血液白细胞中选定的IL-4敏感基因产物的表达。此外，通过反相高效液相色谱（RP-HPLC）分析花生四烯酸氧化产物，对分离得到的单核细胞的脂肪酸氧化酶活性进行测定（离体活性实验）。
**结果：** 本研究发现，特应性患者的血浆IgE与IL-4水平显著升高，但升高幅度不足以上调循环白细胞中选定的IL-4敏感基因的表达。此外，特应性患者血液单核细胞的花生四烯酸氧化酶活性未出现显著改变。
**结论：** 本研究数据表明，特应性患者的血浆IL-4水平未达到足以影响IL-4敏感基因表达的水平。