►在不同的系统性自身免疫性风湿疾病中有不同程度的表现,特别是系统性红斑狼疮、系统性硬化症、混合性结缔组织病、系统性硬化症-自身免疫性肌病重叠综合征和未分化结缔组织病(例如,具有风湿症状但未明确诊断为系统性自身免疫性风湿病的患者)(29)
►对于临床疑似系统性红斑狼疮的患者,建议后续检测抗Sm和U1RNP抗体;这些抗原通常包含在常规的抗可溶性抗原谱检测中;系统性红斑狼疮的分类标准包含抗Sm抗体(16,30,31)
►对于临床疑似系统性硬化症的患者,建议后续检测抗RNApol III抗体(例如,系统性硬化症谱*);抗RNApol III抗体包含于系统性硬化症的分类标准中(8)
►对于临床疑似混合性结缔组织病的患者,建议后续检测抗U1RNP抗体。U1RNP抗原通常包含在常规的ENA谱检测中;抗U1RNP抗体包含于混合性结缔组织病的诊断标准中(32)
►对于临床疑似系统性硬化症-自身免疫性肌病重叠综合征的患者,建议后续检测抗U1RNP抗体和抗Ku抗体;U1RNP抗原包含在常规的抗可溶性抗原谱检测中,抗Ku抗体则包含于疾病特异性免疫检测中(例如,炎症性肌病谱*和系统性硬化症谱*)(26,33)
►对于一般人群中的非系统性自身免疫性风湿疾病个体,AC-5核型的存在与上述自身抗原无关,且通常抗体滴度低。
*炎症性肌病谱、系统性硬化症谱和(扩展的)肝病谱的应用可能仅限于专业的临床实验室。
► Present to a varying degree in distinct SARD, in particular SLE, SSc, MCTD, SSc-AIM overlap syndrome, and UCTD (i.e, patients with rheumatic symptoms without a definite SARD diagnosis) (29)
► If SLE is clinically suspected, it is recommended to perform follow-up tests for anti-Sm and anti-U1RNP antibodies; these antigens are commonly included in the routine ENA profile; anti-Sm antibodies are included in the classification criteria for SLE (16, 30, 31)
► If SSc is clinically suspected, it is recommended to perform a follow-up test for anti-RNApol III antibodies (e.g., SSc profile*); the anti-RNApol III antibodies are included in the classification criteria for SSc (8)
► If MCTD is clinically suspected, it is recommended to perform a follow-up test for anti-U1RNP antibodies; the antigen is commonly included in the routine ENA profile; anti-U1RNP antibodies are included in the diagnostic criteria for MCTD (32)
► If the SSc-AIM overlap syndrome is clinically suspected, it is recommended to perform follow-up tests for anti-U1RNP and anti-Ku antibodies; these antigens are included in the routine ENA profile (U1RNP), or in disease specific immunoassays (Ku, i.e., inflammatory myopathy profile* and SSc profile*) (26, 33)
► In non-SARD individuals in the general population, the presence of the AC-5 pattern is not associated with the autoantigens mentioned above and most often concerns low antibody titers
*Availability of the inflammatory myopathy profile, the SSc profile and the (extended) liver profile may be limited to specialty clinical laboratories.