自體免疫耐受性相關基因之多形性與台灣人僵直性脊椎炎之相關

Association between polymorphisms of autoimmune tolerance-related genes and Taiwanese ankylosing spondylitis

蔡明道(Ming-Dow Tsay)

指導教授 ： 李孟智 ； 翁瑞宏

中山醫學大學/醫學院/醫學研究所/碩士(2010年)

https://doi.org/10.6834/CSMU.2010.00054

摘要

背景：免疫耐受性之失衡已經被發現與自體免疫疾病之發生具有相關性，而CD4+ T細胞以及CD8+ T細胞也被發現在僵直性脊椎炎 (ankylosing spondylitis；AS) 病患中相較於健康對照有較高的表現，如此的表現可能與活化T細胞的抑制訊息失衡具有相關性。特別的是，第四類細胞毒殺性T淋巴抗原 (cytotoxic T lymphocyte antigen-4；CTLA-4) 可能在自體免疫耐受性的初期扮演著 抑制過度活化T細胞的角色，而計畫性細胞死亡-1 (programmed cell death-1；PD-1) 與計畫性細胞死亡-1配位基-1 (programmed cell death-1 ligand 1；PD-L1) 和計畫性細胞死亡-1配位基-2 (programmed cell death-1 ligand 2；PD-L2) 鍵結的抑制訊息可能作用在免疫耐受性的晚期及後續之平衡的維持。然而，自體免疫耐受性相關基因於僵直性脊椎炎發展中之分子角色是不清楚的。因此，我們設計一個以醫院為基礎的病例對照研究來評估CTLA-4以及PD-1、PD-L1和PD-L2基因多形性是否相關於僵直性脊椎炎的發生及其臨床表徵。

材料與方法：在我們的研究中，納入了325名僵直性脊椎炎病患與325名以性別及年齡配對的健康對照，利用聚合酶鏈鎖反應-限制酵素片段長度多形性 (polymerase chain reaction-restriction fragment length polymorphism) 來判定CTLA-4 A+49G以及PD-1 G-536A、PD-L1 A8923C和PD-L2 C47103T基因型；僵直性脊椎炎病患之疾病活性與功能狀態則藉由巴斯僵直性脊椎炎疾病活性指數 (Bath Ankylosing Spondylitis Disease Activity Index；BASDAI)、巴斯僵直性脊椎炎功能性指數 (Bath Ankylosing Spondylitis Functional Index；BASFI)、以及巴斯僵直性脊椎炎健康綜合評分 (Bath Ankylosing Spondylitis Global；BAS-G) 來評估。

結果：我們的結果顯示，攜帶PD-1 G對偶基因者相較於A對偶基因者具有1.42倍 (95% confidence interval；95% C.I. = 1.14-1.76) 的僵直性脊椎炎顯著發生危險；而攜帶PD-L2 T對偶基因者相較於C對偶基因者也具有顯著較低的疾病發生危險 (relative risk；RR = 0.01；95% C.I. = 0.001-0.070)。此外，同時攜帶PD-1 GG或GA、PD-L1 CC、以及PD-L2 CC基因型者具有僵直性脊椎炎發生的顯著合併效應 (RR = 7.17；95% C.I. = 1.38-37.31)。相較於CTLA-4 GG與PD-1 AA合併基因型之攜帶者，CTLA-4 AA或AG與PD-1 GG或GA合併基因型攜帶者具有2.30倍 (95% C.I. = 1.27-4.16) 的疾病發生危險。

結論：結果顯示CTLA-4以及PD-1、PD-L1和PD-L2基因可能相關於僵直性脊椎炎病患之自體免疫耐受性的失衡。

關鍵字

免疫耐受性 ； 僵直性脊椎炎 ； 第四類細胞毒殺性T淋巴抗原 ； 計畫性細胞死亡-1 ； 計畫性細胞死亡-1配位基

並列摘要

Background：Imbalance of immune tolerance had been found to associate with the occurrence of autoimmune diseases. The CD4+ and CD8+ T cells had also been revealed more predominant expression in ankylosing spondylitis (AS) patients than healthy controls, and such expression may relate to the imbalance in the negative signal of activated T cells. Especially, cytotoxic T lymphocyte antigen-4 (CTLA-4) might play a role in the inhibition of activated T cells in the initial period of autoimmune tolerance. Programmed cell death-1(PD-1) binds its ligands, programmed cell death-1 ligand 1(PD-L1) and programmed cell death-1 ligand 2 (PD-L2), and induced negative signals that might maintain the balance of immune tolerance during late and sequential periods. However, molecular roles of autoimmune tolerance-related genes in AS development are unclear. Therefore, we designed a hospital-based case-control study to evaluate the association between CTLA-4, PD-1, PD-L1, and PD-L2 genetic polymorphisms and AS occurrences and clinical manifestations.

Methods and Materials：A total of 325 AS patients and 325 age and gender-matched controls were recruited in our study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to identify the CTLA-4 A+49G, PD-1 G-536A, PD-L1 A8923C, and PD-L2 C47103T genotypes. The disease activity and functional status of AS patients were evaluated by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Bath Ankylosing Spondylitis Global (BAS-G).

Results：Our results showed that those who carried PD-1 G-536A G allele had a 1.42 fold (95% confidence interval; 95% C.I. = 1.14-1.76) significant risk of AS than those with A allele. Those who carried PD-L2 T allele also had a significantly lower risk of AS development than those with C allele (relative risk; RR = 0.01; 95% C.I. = 0.001-0.070). In addition, those who simultaneously carried PD-1 GG or GA, PD-L1 CC, and PD-L2 CC genotypes had a significant combined effect in AS occurrence (RR = 7.17; 95% C.I. = 1.38-37.31). Compared to the carriers with CTLA-4 GG and PD-1 AA combined genotypes, the carriers with CTLA-4 AA or AG and PD-1 GG or GA genotypes had a 2.30 fold (95% C.I. = 1.27-4.16) risk for disease development.

Conclusion：These results show that CTLA-4, PD-1, PD-L1, and PD-L2 genes may associate with the imbalance of autoimmune tolerance in AS patients.

並列關鍵字

immune tolerance ； ankylosing spondylitis ； cytotoxic T lymphocyte antigen-4 ； programmed cell death-1 ； programmed cell death-1 ligands

參考文獻

26. Shih HC. Liu SC. Chang CP. Tschen JS. Chiu HY. Liu HC. Chang JG. Positive association of ankylosing spondylitis with homozygous HLA-B2704, but protection with B2705 in Taiwan Chinese. Kaohsiung Journal of Medical Sciences. 17(10):509-16, 2001.

1. Olivieri I. van Tubergen A. Salvarani C. van der Linden S. Seronegative spondyloarthritides. Best Practice and Research in Clinical Rheumatology. 16(5):723-39, 2002.

2. Masi AT. Walsh EG. Ankylosing spondylitis: integrated clinical and physiological perspectives. Clinical and Experimental Rheumatology. 21(1):1-8, 2003.

3. Feldtkeller E. Bruckel J. Khan MA. Scientific contributions of ankylosing spondylitis patient advocacy groups. Current Opinion in Rheumatology. 12(4):239-47, 2000.

6. Calin A. Brophy S. Blake D. Impact of sex on inheritance of ankylosing spondylitis: a cohort study. Lancet. 354(9191):1687-90, 1999.