Paranos S, Petrović S, Vojović I
Department of Allergology and Clinical Immunology, Zvezdara University Medical Centre, Belgrade.
Srp Arh Celok Lek. 1998 Sep-Oct;126(9-10):362-7.
Skin tests are the most useful single modality for demonstrating an IgE-mediated mechanism underlying clinical symptoms. Skin reactivity to an allergen depends on person's exposure and genetic factors influencing the IgE response. However, the reproducibility of allergy skin tests has been shown to be variable depending, among other things, on the allergen extract employed and the kind of technique used. These variations have led to controversy regarding clinical relevancy of allergy skin testing [1-7]. We examined the relationship of skin-prick test and serum allergen-specific IgE in pollen susceptible adult persons. We estimated changes in the immediate skin reactivity to pollen-allergens by testing patients on more than one occasion: a) during and out of pollen season; b) before and after completing specific immunotherapy, and c) who had been tested with diverse concentrations of the same pollen-allergen. We correlated the degree of skin reactivity at the initial and subsequent testings with the aim of estimate diagnostic relevancy of such performed allergy skin testings.
Study was performed in 64 persons (aged from 17 to 43 years) suffering from rhinitis or rhinoconjunctivitis or asthma. They were diagnosed for the first time [8, 9]. None of selected persons had proven dermographism [1, 9]. Study protocol Skin prick tests were performed according to recommended protocol reviewed elsewhere [9]. Blood samples for total and allergen-specific IgE were taken in the morning on the test-day and sera were stored until analyses. Testing was performed with in house standardized extract of grass pollens (each of 5000 AU/allergy unit per milliliter): Dactylis glomerata and Phleum pratense and Lolium perenne (produced by Torlak Institute, Belgrade). Testing was performed in selected groups of patients: a) during and out of pollen season; b) before and after allergen-specific immunotherapy, and c) with three diverse concentrations of Phleum pratense allergenic extract (5000 AU, 7500 AU and 10,000 AU/ml). During the study a medication was not allowed at least 7 days prior to the skin testing (14 days for hydroxyzine). Alergen-specific IgE in serum (RAST) Determination of serum allergen-specific IgE was performed by using commercially available Pharmacia kit (EIA RAST Phadesim). For allergen-specific IgE results were expressed in classes (1 minimal to 4-maximal concentrations) determined by manufacturer. Study was performed under approval of the Ethic Committee of our hospital. For statistical analysis we used t-test and test of variance (ANOVA). Results were considered significant if p < 0.05.
Influence of allergen-specific serum IgE concentration on local skin reactivity was estimated in 23 persons (17 females, 6 males), and is shown in Table 1. The largest papule diameter was registered in high susceptible persons (RAST class 4). Influences of season when testing was performed and specific immunotherapy were estimated in 26 persons (19 females, 7 males) (Figures 1 and 2). The effect of diverse allergenic extract concentrations was estimated in 15 adults (9 females, 6 males, mean age 26.4 years) and results are shown in Figure 3.
In the study it has been shown that serum concentration of allergen-specific IgE positively correlated with the skin reactivity to pollen-extract. In addition, allergen specific immunotherapy as well as the concentrations of the used allergenic extract influenced significantly local skin reactivity. On the contrary, season when testing had no influence. According to our results, it seems that skin reactions (papule), equal or larger than 6 mm in diameter, could be of diagnostic value concerning pollen-monotest application (Table 1). Meanwhile, with significance of 95% we could postulate that in persons tested with the lowest concentration of allergen-solution (5000 AU/ml), skin prick reactivity defined by the papule of 4 mm or larger can replace in vitro
皮肤试验是证明临床症状背后IgE介导机制的最有用的单一方法。皮肤对过敏原的反应性取决于个体的接触情况以及影响IgE反应的遗传因素。然而，过敏皮肤试验的可重复性已被证明存在差异，这尤其取决于所使用的过敏原提取物和技术类型。这些差异引发了关于过敏皮肤试验临床相关性的争议[1-7]。我们研究了花粉敏感成人中皮肤点刺试验与血清过敏原特异性IgE的关系。我们通过在多个时间点对患者进行测试来评估对花粉过敏原的即时皮肤反应性的变化：a）在花粉季节期间和非花粉季节；b）在完成特异性免疫治疗之前和之后；c）用不同浓度的同一种花粉过敏原进行测试。我们将初始和后续测试时的皮肤反应程度进行关联，以评估此类过敏皮肤试验的诊断相关性。
对64名（年龄在17至43岁之间）患有鼻炎、鼻结膜炎或哮喘的患者进行了研究。他们均为首次诊断[8,9]。所选患者均未证实有皮肤划痕症[1,9]。研究方案 皮肤点刺试验按照其他地方审查的推荐方案进行[9]。在测试当天早晨采集用于检测总IgE和过敏原特异性IgE的血样，血清保存直至分析。使用内部标准化的禾本科花粉提取物（每毫升各含5000 AU/过敏单位）进行测试：鸭茅、梯牧草和多年生黑麦草（由贝尔格莱德的Torlak研究所生产）。在选定的患者组中进行测试：a）在花粉季节期间和非花粉季节；b）在过敏原特异性免疫治疗之前和之后；c）用梯牧草过敏原提取物的三种不同浓度（5000 AU、7500 AU和10,000 AU/ml）。在研究期间，在皮肤测试前至少7天不允许用药（羟嗪为14天）。血清过敏原特异性IgE（RAST） 使用市售的Pharmacia试剂盒（EIA RAST Phadesim）测定血清过敏原特异性IgE。过敏原特异性IgE结果以制造商确定的类别（1为最低浓度至4为最高浓度）表示。本研究在我院伦理委员会批准下进行。为进行统计分析，我们使用了t检验和方差分析（ANOVA）。如果p < 0.05，则结果被认为具有统计学意义。
在23名患者（17名女性，6名男性）中评估了过敏原特异性血清IgE浓度对局部皮肤反应性的影响，结果见表1。在高敏患者（RAST 4级）中记录到最大的丘疹直径。在26名患者（19名女性，7名男性）中评估了测试季节和特异性免疫治疗的影响（图1和图2）。在15名成年人（9名女性，6名男性，平均年龄26.4岁）中评估了不同过敏原提取物浓度的影响，结果见图3。
在本研究中已表明，过敏原特异性IgE的血清浓度与皮肤对花粉提取物的反应性呈正相关。此外，过敏原特异性免疫治疗以及所用过敏原提取物的浓度对局部皮肤反应性有显著影响。相反，测试季节没有影响。根据我们的结果，似乎直径等于或大于6 mm的皮肤反应（丘疹）对于花粉单一测试的应用可能具有诊断价值（表1）。同时，在95%的显著性水平下，我们可以假定，在用最低浓度的过敏原溶液（5000 AU/ml）进行测试的患者中，直径为4 mm或更大丘疹所定义 的皮肤点刺反应性可以替代体外检测
