Lucchesi Davide, Coleby Rachel, Pontarini Elena, Prediletto Edoardo, Rivellese Felice, Hill David G, Derrac Soria Alicia, Jones Simon A, Humphreys Ian R, Sutcliffe Nurhan, Tappuni Anwar R, Pitzalis Costantino, Jones Gareth W, Bombardieri Michele
Queen Mary University of London, London, UK.
Cardiff University, Cardiff, UK, and University of Bristol, Bristol, UK.
Arthritis Rheumatol. 2020 Sep;72(9):1559-1570. doi: 10.1002/art.41289. Epub 2020 Jul 21.
Ectopic lymphoid structures (ELS) develop at sites of infection, autoimmunity, and cancer. In patients with Sjögren's syndrome (SS), ELS support autoreactive B cell activation and lymphomagenesis. Interleukin-27 (IL-27) is a key regulator of adaptive immunity and limits Th17 cell-driven pathology. We undertook this study to elucidate the role of IL-27 in ELS formation and function in autoimmunity using a murine model of sialadenitis and in patients with SS.
ELS formation was induced in wild-type and Il27ra mice via salivary gland (SG) cannulation of a replication-deficient adenovirus in the presence or absence of IL-17A neutralization. In SG biopsy samples, IL-27-producing cells were identified by multicolor immunofluorescence microscopy. Lesional and circulating IL-27 levels were determined by gene expression and enzyme-linked immunosorbent assay. The in vitro effect of IL-27 on T cells was assessed using fluorescence-activated cell sorting and cytokine release.
In experimental sialadenitis, Il27ra mice had larger and more hyperactive ELS (focus score; P < 0.001), increased autoimmunity, and an expanded Th17 response (P < 0.001), compared to wild-type mice. IL-17 blockade in Il27ra mice suppressed the aberrant ELS response (B and T cell reduction against control; P < 0.01). SS patients displayed increased circulating IL-27 levels (P < 0.01), and in SG biopsy samples, IL-27 was expressed by DC-LAMP+ dendritic cells in association with CD3+ T cells. Remarkably, in SS T cells (but not in T cells from patients with rheumatoid arthritis or healthy controls), IL-27-mediated suppression of IL-17 secretion was severely impaired and associated with an aberrant interferon-γ release upon IL-27 stimulation.
Our data indicate that the physiologic ability of IL-27 to limit the magnitude and function of ELS through control of Th17 cell expansion is severely impaired in SS patients, highlighting a defective immunoregulatory checkpoint in this condition.
异位淋巴样结构（ELS）在感染、自身免疫和癌症部位形成。在干燥综合征（SS）患者中，ELS支持自身反应性B细胞活化和淋巴瘤发生。白细胞介素-27（IL-27）是适应性免疫的关键调节因子，可限制Th17细胞驱动的病理过程。我们进行这项研究，以使用涎腺炎小鼠模型和SS患者来阐明IL-27在自身免疫中ELS形成和功能中的作用。
在存在或不存在IL-17A中和的情况下，通过对野生型和Il27ra小鼠进行复制缺陷型腺病毒的唾液腺（SG）插管来诱导ELS形成。在SG活检样本中，通过多色免疫荧光显微镜鉴定产生IL-27的细胞。通过基因表达和酶联免疫吸附测定法测定病变组织和循环中的IL-27水平。使用荧光激活细胞分选和细胞因子释放评估IL-27对T细胞的体外作用。
在实验性涎腺炎中，与野生型小鼠相比，Il27ra小鼠具有更大且更活跃的ELS（病灶评分；P < 0.001），自身免疫增加，以及Th17反应扩大（P < 0.001）。Il27ra小鼠中的IL-17阻断抑制了异常的ELS反应（与对照相比B细胞和T细胞减少；P < 0.01）。SS患者循环中的IL-27水平升高（P < 0.01），并且在SG活检样本中，IL-27由DC-LAMP +树突状细胞与CD3 + T细胞共同表达。值得注意的是，在SS T细胞中（但在类风湿性关节炎患者或健康对照的T细胞中未观察到），IL-27介导的IL-17分泌抑制严重受损，并且与IL-27刺激后异常的干扰素-γ释放相关。
我们的数据表明，在SS患者中，IL-27通过控制Th17细胞扩增来限制ELS大小和功能的生理能力严重受损，突出了这种情况下免疫调节检查点的缺陷。
