►可见于系统性硬化症、系统性硬化症-自身免疫性肌病重叠综合征，及有其他系统性自身免疫性风湿疾病临床表现的患者(44-46)。

►若临床疑似局限皮肤型系统性硬化症，推荐进一步检测抗Th/To抗体。该抗原包含在疾病特异性免疫检测试剂中（例如，系统性硬化症谱*）(44,45)。

►若临床疑似系统性硬化症-自身免疫性肌病重叠综合征，推荐进一步检测抗PM/Scl抗体。该抗原可能包含在常规ENA谱中，也包含在疾病特异性免疫检测试剂中（例如，炎症性肌病谱*与系统性硬化症谱*）。大体上，抗PM/Scl抗体会在AC-8核型基础上出现弥散的细胞核致密颗粒荧光(46)。

►其他已被识别的抗原包括B23/核仁磷酸蛋白（nucleophosmin）、No55/SC65、C23/核仁素（nucleolin）等，但相应自身抗体的临床意义尚不明确。目前尚无针对这些自身抗体的商品化免疫检测试剂。

注：尽管已有商品化的抗Th/To抗体免疫检测试剂，但应充分考虑其低敏感性等技术问题(44,47)。

*炎症性肌病谱、系统性硬化症谱及肝病谱（扩展版）等检测试剂可能仅供临床专业实验室使用。

► Found in patients with SSc, SSc-AIM overlap syndrome, and patients with clinical manifestations of other SARD (44–46)

► If limited cutaneous SSc is clinically suspected, it is recommended to perform a follow-up test for anti-Th/To antibodies; the antigen is included in disease specific immunoassays (i.e., SSc profile*) (44, 45)

► If SSc-AIM overlap syndrome is clinically suspected, it is recommended to perform a follow-up test for anti-PM/Scl antibody reactivity; the antigen may be included in the routine ENA profile and is included in disease specific immunoassays (i.e., inflammatory myopathy profile* and the SSc profile*); in general, anti-PM/Scl antibodies yield a diffuse nuclear fine speckled staining in addition to the AC-8 pattern (46)

► Other antigens recognized include B23/nucleophosmin, No55/SC65, and C23/nucleolin, but the clinical significance of these autoantibodies is not well established; specific immunoassays for these autoantibodies are currently not commercially available

Notes: Although some anti-Th/To antibody immunoassays are commercially available, technical issues relating to the limited sensitivity of these immunoassays should be taken in to consideration (44, 47).

*Availability of the inflammatory myopathy profile, the SSc profile and the (extended) liver profile may be limited to specialty clinical laboratories.

44. Mahler M, Fritzler MJ, Satoh M. Autoantibodies to the mitochondrial RNA processing (MRP) complex also known as Th/To autoantigen. Autoimmun Rev 2015;14:254–7.

45. Ceribelli A, Cavazzana I, Franceschini F, et al. Anti-Th/To are common antinucleolar autoantibodies in Italian patients with scleroderma. J Rheumatol 2010;37:2071–5.

46. Mahler M, Raijmakers R. Novel aspects of autoantibodies to the PM/Scl complex: clinical, genetic and diagnostic insights. Autoimmun Rev 2007;6:432–7.

47. Mahler M, Gascon C, Patel S, et al. Rpp25 is a major target of autoantibodies to the Th/To complex as measured by a novel chemiluminescent assay. Arthritis Res Ther 2013;15.

44. Mahler M, Fritzler MJ, Satoh M. Autoantibodies to the mitochondrial RNA processing (MRP) complex also known as Th/To autoantigen. Autoimmun Rev 2015;14:254–7.

45. Ceribelli A, Cavazzana I, Franceschini F, et al. Anti-Th/To are common antinucleolar autoantibodies in Italian patients with scleroderma. J Rheumatol 2010;37:2071–5.

46. Mahler M, Raijmakers R. Novel aspects of autoantibodies to the PM/Scl complex: clinical, genetic and diagnostic insights. Autoimmun Rev 2007;6:432–7.

47. Mahler M, Gascon C, Patel S, et al. Rpp25 is a major target of autoantibodies to the Th/To complex as measured by a novel chemiluminescent assay. Arthritis Res Ther 2013;15.

►因抗Th/To反应性导致的AC-8核型也可见于系统性红斑狼疮、未分化的结缔组织病（例如，患者有风湿性临床特征，但无法诊断为系统性自身免疫性风湿疾病）、无皮肤硬化的系统性硬化症、特发性间质性肺病或肺动脉高压患者(20,21)。

►对于因抗PM/Scl反应性导致的AC-8核型，其患者可能在自身免疫性肌病和系统性硬化症临床特征以外，出现多种系统性红斑狼疮和干燥综合征临床表现(22)。

► The AC‐8 pattern that is the result of the anti‐Th/To reactivity is also seen in patients with SLE, UCTD (i.e., patients with rheumatic symptoms without a SARD diagnosis), SSc sine scleroderma, idiopathic interstitial lung disease or pulmonary hypertension (20, 21)

► Patients with autoantibodies revealing the AC‐8 pattern due to anti‐PM/Scl reactivity may have, in addition to the clinical features of AIM and SSc, various clinical manifestations of SLE and SjS (22)

20. Fischer A, Pfalzgraf FJ, Feghali‐Bostwick CA, et al. Anti‐Th/To‐Positivity in a Cohort of Patients with Idiopathic Pulmonary Fibrosis. J Rheumatol 2006;33:1600‐1605.

21. Fischer A, Meehan RT, Feghali‐Bostwick CA, et al. Unique characteristics of systemic sclerosis sine scleroderma‐associated interstitial lung disease. Chest 2006;130:976‐981.

22. Mahler M, Raijmakers R. Novel aspects of autoantibodies to the PM/Scl complex: clinical, genetic and diagnostic insights. Autoimmun Rev 2007;6:432‐437.

20. Fischer A, Pfalzgraf FJ, Feghali‐Bostwick CA, et al. Anti‐Th/To‐Positivity in a Cohort of Patients with Idiopathic Pulmonary Fibrosis. J Rheumatol 2006;33:1600‐1605.

21. Fischer A, Meehan RT, Feghali‐Bostwick CA, et al. Unique characteristics of systemic sclerosis sine scleroderma‐associated interstitial lung disease. Chest 2006;130:976‐981.

22. Mahler M, Raijmakers R. Novel aspects of autoantibodies to the PM/Scl complex: clinical, genetic and diagnostic insights. Autoimmun Rev 2007;6:432‐437.