Claass A, Sommer M, de Jonge H R
Klinik für Allgemeine Pädiatrie, Christian-Albrechts- Universität zu Kiel, Germany.
Histochem J. 2000 Oct;32(10):617-24. doi: 10.1023/a:1026744707198.
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause the hereditary disease cystic fibrosis. The most frequent mutant deltaF508 has been shown in vitro to be retained in the endoplasmic reticulum. Ex vivo studies using immunohistochemical labelling in cryofixed skin biopsies have confirmed the mislocalization of deltaF508 CFTR in sweat glands. The purpose of this study was to test CFTR antibodies in paraffin-embedded skin biopsies to take advantage of the superior tissue preservation as compared to cryofixation. A panel of 7 CFTR antibodies was applied to skin sections of healthy controls and of cystic fibrosis patients homozygous for the deltaF508 mutation. Sweat gland labelling consistent with CFTR localization and different between control and cystic fibrosis tissue was obtained with 2 antibodies. Conventional staining controls confirmed the labelling specificity. The antibodies were subsequently tested in a series of 237 sections of 16 biopsy specimens. However, the sweat gland labelling pattern proved not to be dependent on CFTR genotype. This finding was the sole indicator of non-specificity of the staining which was revealed only by the size of our random sample. Our results emphasize that CFTR immunolabelling following formalin fixation has to be interpreted with the utmost caution.
囊性纤维化跨膜传导调节因子（CFTR）基因的突变会导致遗传性疾病囊性纤维化。最常见的突变体deltaF508在体外已被证明滞留在内质网中。使用免疫组织化学标记对冷冻固定的皮肤活检组织进行的体外研究证实了deltaF508 CFTR在汗腺中的定位错误。本研究的目的是在石蜡包埋的皮肤活检组织中检测CFTR抗体，以利用与冷冻固定相比更好的组织保存效果。一组7种CFTR抗体应用于健康对照者和deltaF508突变纯合的囊性纤维化患者的皮肤切片。用2种抗体获得了与CFTR定位一致且对照组织和囊性纤维化组织之间存在差异的汗腺标记。传统染色对照证实了标记的特异性。随后在16个活检标本的237个切片系列中对抗体进行了检测。然而，汗腺标记模式被证明不依赖于CFTR基因型。这一发现是染色非特异性的唯一指标，仅通过我们随机样本的大小才揭示出来。我们的结果强调，福尔马林固定后的CFTR免疫标记必须极其谨慎地进行解读。
