Hancock A, Armstrong L, Gama R, Millar A
Department of Hospital Medicine, University of Bristol Medical School Unit, Southmead Hospital, Westbury on Trym, United Kingdom.
Am J Respir Cell Mol Biol. 1998 Jan;18(1):60-5. doi: 10.1165/ajrcmb.18.1.2627.
Human interleukin 13 (IL-13) is a cytokine that has a profound effect on primary immune cells by inducing immunoglobulin production, proliferation of B cells, and the differentiation of cells of the monocytic lineage. IL-13 can inhibit the production of inflammatory cytokines by both macrophages and monocytes. Previously, IL-13 expression has been reported only in cells of the T-cell lineage and the mast cell line HMC-1. We now report the presence of IL-13 mRNA and protein in human alveolar macrophages (AMs) analyzed by the reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunoabsorbent assay (ELISA), respectively, and IL-13 protein in bronchoalveolar lavage fluid (BALF) of subjects with pulmonary fibrosis. We have investigated 13 patients from 49 to 75 yr of age with forms of pulmonary fibrosis, and eight healthy volunteers from 24 to 61 yr of age. Their AMs were obtained by bronchoalveolar lavage (BAL) and purified by adherence. The proportion of BAL purified AMs expressing IL-13 mRNA was increased in those subjects with fibrotic lung disease, in comparison with those from control subjects (11 of 13 versus 2 of 8, P < 0.01). IL-13 protein was detectable in the BALF of 8 of 13 patients with pulmonary fibrosis, but in none of the control subjects. AMs of four subjects with systemic sclerosis were cultured and IL-13 protein was increased in the culture supernatants when compared to the control subjects, although this did not reach significance. These findings show that IL-13 mRNA is not only a product of T cells, but is also expressed in both normal AMs and those from subjects with pulmonary fibrosis, and that at least some of the IL-13 mRNA is translated into protein and secreted in subjects with pulmonary fibrosis. We hypothesize that IL-13 may be expressed by normal human AMs as part of the homeostatic control process but its production may be increased in the presence of inflammatory lung disease.
人白细胞介素13（IL-13）是一种细胞因子，通过诱导免疫球蛋白产生、B细胞增殖以及单核细胞系细胞分化，对初级免疫细胞产生深远影响。IL-13可抑制巨噬细胞和单核细胞产生炎性细胞因子。此前，仅报道IL-13在T细胞系细胞和肥大细胞系HMC-1中表达。我们现在分别通过逆转录-聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）报告了在人肺泡巨噬细胞（AM）中存在IL-13 mRNA和蛋白，以及在肺纤维化患者的支气管肺泡灌洗液（BALF）中存在IL-13蛋白。我们研究了13例年龄在49至75岁之间的肺纤维化患者以及8例年龄在24至61岁之间的健康志愿者。通过支气管肺泡灌洗（BAL）获取他们的AM，并通过贴壁法进行纯化。与对照组相比，纤维化肺病患者中表达IL-13 mRNA的BAL纯化AM的比例增加（13例中的11例对8例中的2例，P<0.01）。13例肺纤维化患者中有8例的BALF中可检测到IL-13蛋白，但对照组中均未检测到。培养了4例系统性硬化症患者的AM，与对照组相比，培养上清液中IL-13蛋白增加，尽管未达到显著水平。这些发现表明，IL-13 mRNA不仅是T细胞的产物，在正常AM以及肺纤维化患者的AM中也有表达，并且在肺纤维化患者中至少部分IL-13 mRNA被翻译成蛋白并分泌。我们推测，正常人类AM可能表达IL-13作为稳态控制过程的一部分，但在炎性肺病存在时其产生可能会增加。
