Kaan P M, Hegele R G, Hayashi S, Hogg J C
Department of Pathology and Laboratory Medicine, Univesity of British Columbia, St Paul's Hospital, Vancouver, Canada.
Thorax. 1997 Jan;52(1):12-6. doi: 10.1136/thx.52.1.12.
Epstein-Barr virus (EBV) genome has been demonstrated in lung tissues of patients with lymphocytic interstitial pneumonia (LIP) but its role in the pathogenesis of this condition is unclear. In vitro studies have shown that EBV can immortalise and transform cells by upregulation of the cellular proto-oncogene, B cell leukaemia-2 (bcl-2), via the viral latent membrane protein, LMP1. The purpose of this study was to determine whether bcl-2 expression is upregulated in the lungs of patients with LIP and whether EBV LMP1 has a role in this bcl-2 expression.
Immunohistochemical analysis using alkaline phosphatase anti-alkaline phosphatase (APAAP) was performed on formalin fixed, paraffin embedded lung tissues from 13 patients with LIP using anti-LMP1 and anti-bcl-2 monoclonal antibodies. Lung tissues from nine patients with idiopathic pulmonary fibrosis (IPF) and nine necropsy cases without pulmonary disease served as controls. LMP1 positivity was estimated as the number of LMP1 positive cells per unit area of lung tissue. Immunostaining for bcl-2 expression was assessed by a pictorial-based semiquantitative grading system.
Positive immunostaining for LMP1 was localised to airway epithelial cells of lung tissue. Ten out of 13 (77%) patients with LIP were positive for LMP1 compared with three of nine cases (33%) in each control group. LMP1 positivity of LIP cases was significantly greater than that of non-LIP cases: LIP versus IPF (mean difference, 95% confidence interval (CI)) 2.39 (1.54 to 3.24); LIP versus necropsy controls 2.62 (1.77 to 3.47). bcl-2 immunostaining was localised to lymphocytes within the alveolar septa and lymphoid aggregates of patients with LIP. The cumulative score for bcl-2 immunostaining was significantly higher in the lungs of patients with LIP than in those of patients with IPF and necropsy controls: LIP versus IPF and LIP versus necropsy controls (mean difference, 95% CI) 7.55 (7.18 to 7.92).
These immunohistochemical studies have shown the presence of EBV LMP1 protein in airway epithelial cells and overexpression of the cellular bcl-2 protein in lymphoid cells of lung tissue in patients with LIP. These geographically distinct staining patterns of immunostaining suggest that the involvement of EBV LMP1 in the upregulation of cellular bcl-2 is more complex in LIP than was thought from previous in vitro observations. The respective roles of EBV LMP1 and bcl-2 in the pathogenesis of LIP require further studies.
在淋巴细胞性间质性肺炎（LIP）患者的肺组织中已证实存在爱泼斯坦-巴尔病毒（EBV）基因组，但其在该病发病机制中的作用尚不清楚。体外研究表明，EBV可通过病毒潜伏膜蛋白LMP1上调细胞原癌基因B细胞白血病-2（bcl-2），从而使细胞永生化并发生转化。本研究旨在确定LIP患者肺组织中bcl-2表达是否上调，以及EBV LMP1在这种bcl-2表达中是否起作用。
使用抗LMP1和抗bcl-2单克隆抗体，对13例LIP患者经福尔马林固定、石蜡包埋的肺组织进行碱性磷酸酶抗碱性磷酸酶（APAAP）免疫组织化学分析。9例特发性肺纤维化（IPF）患者的肺组织和9例无肺部疾病的尸检病例作为对照。LMP1阳性率以肺组织单位面积内LMP1阳性细胞数来估计。通过基于图像的半定量分级系统评估bcl-2表达的免疫染色情况。
LMP1的阳性免疫染色定位于肺组织的气道上皮细胞。13例LIP患者中有10例（77%）LMP1呈阳性，而每个对照组的9例病例中有3例（33%）呈阳性。LIP病例的LMP1阳性率显著高于非LIP病例：LIP与IPF（平均差异，95%置信区间（CI））2.39（1.54至3.24）；LIP与尸检对照2.62（1.77至3.47）。bcl-2免疫染色定位于LIP患者肺泡间隔和淋巴样聚集区内的淋巴细胞。LIP患者肺组织中bcl-2免疫染色的累积评分显著高于IPF患者和尸检对照：LIP与IPF以及LIP与尸检对照（平均差异，95%CI）7.55（7.18至7.92）。
这些免疫组织化学研究表明，LIP患者气道上皮细胞中存在EBV LMP1蛋白，肺组织淋巴样细胞中细胞bcl-2蛋白过表达。这些免疫染色在地理位置上不同的模式表明，EBV LMP1参与细胞bcl-2上调在LIP中比以前体外观察所认为的更为复杂。EBV LMP1和bcl-2在LIP发病机制中的各自作用需要进一步研究。
