Takahashi K, MacDonald G D, Kinane D F
Department of Periodontology and Endodontology, Okayama University Dental School, Japan.
J Endod. 1997 Aug;23(8):513-6. doi: 10.1016/S0099-2399(97)80312-3.
Humoral immune responses are implicated in the pathogenesis of human dental periapical lesions. To elucidate whether IgA-associated immune systems play a role in the lesions, the in situ hybridization technique was used to detect J chain mRNA expression, which is correlated with the secretion of dimeric IgA. In addition, IgA subclass mRNA-expressing cells were also investigated by double target in situ hybridization (ISH) methodology using digoxigenin- and biotin-labeled IgA subclass specific oligonucleotide probes. This double target ISH technique involved immunochemical detection with an alkaline phosphatase-conjugated antibody and a peroxidase conjugated avidin-biotin complex system to detect IgA subclass mRNA in the formalin-fixed, paraffin wax embedded periapical tissue sections. Twenty-four biopsy samples (16 periapical granulomas and 8 radicular cysts) were examined. IgA subclass mRNA positive plasma cells were detected in all samples. IgA1 mRNA-expressing cells were predominant both in granulomas and cysts (mean = 75.3 +/- 11.2%, 64.8 +/- 21.3%, respectively), and the IgA1 proportion was higher in granulomas than in cysts, although no significant difference was seen between the two lesions (p = 0.132). J chain mRNA positive cells were very sparsely detected in 21/24 cases. The median percentages of J chain mRNA positive cells/IgA mRNA positive plasma cells (4.7%, range 0.3-13.6%) in cysts were significantly higher than in granulomas (1.3%, range 0-7.7%; p = 0.03). This result supports the hypothesis that dimeric IgA may be more actively produced in radicular cysts than in granulomas. These features are thought to reflect the local activation of the periapical immune system in response to environmental factors and indicate that secretory IgA mediated immune defense systems appear to play little role in these lesions. Our results indicate that the IgA-associated immune response in periapical lesions is more similar to serum or systemic IgA responses than to mucosa-associated immune responses where dimeric IgA predominates.
体液免疫反应与人类根尖周病变的发病机制有关。为了阐明与IgA相关的免疫系统是否在这些病变中起作用，采用原位杂交技术检测与二聚体IgA分泌相关的J链mRNA表达。此外，还使用地高辛和生物素标记的IgA亚类特异性寡核苷酸探针，通过双靶点原位杂交（ISH）方法研究表达IgA亚类mRNA的细胞。这种双靶点ISH技术涉及用碱性磷酸酶偶联抗体和过氧化物酶偶联抗生物素蛋白-生物素复合物系统进行免疫化学检测，以检测福尔马林固定、石蜡包埋的根尖周组织切片中的IgA亚类mRNA。检查了24份活检样本（16例根尖周肉芽肿和8例根囊肿）。在所有样本中均检测到IgA亚类mRNA阳性浆细胞。表达IgA1 mRNA的细胞在肉芽肿和囊肿中均占主导（分别平均为75.3±11.2%和64.8±21.3%），肉芽肿中的IgA1比例高于囊肿，尽管两者之间无显著差异（p = 0.132）。在24例中的21例中非常稀疏地检测到J链mRNA阳性细胞。囊肿中J链mRNA阳性细胞/Iga mRNA阳性浆细胞的中位数百分比（4.7%，范围0.3 - 13.6%）显著高于肉芽肿（1.3%，范围0 - 7.7%；p = 0.03）。这一结果支持了以下假设，即根囊肿中二聚体IgA的产生可能比肉芽肿中更活跃。这些特征被认为反映了根尖周免疫系统对环境因素做出反应的局部激活，并表明分泌型IgA介导的免疫防御系统在这些病变中似乎作用不大。我们的结果表明，根尖周病变中与IgA相关的免疫反应更类似于血清或全身性IgA反应，而不是以二聚体IgA为主的黏膜相关免疫反应。
