Vlachoyiannopoulos P G, Guialis A, Tzioufas G, Moutsopoulos H M
Department of Pathophysiology, University of Athens, Medical School, Greece.
Br J Rheumatol. 1996 Jun;35(6):534-41. doi: 10.1093/rheumatology/35.6.534.
Anti-U1RNP antibodies occur in patients with mixed connective tissue disease (MCTD), systemic sclerosis (SSc), systemic lupus erythematosus (SLE) and other ill-defined connective tissue diseases. To associate the isotypes of anti-U1RNP antibodies with the diagnosis of the disease, namely SLE or MCTD, sequential sera of patients positive for anti-U1RNP antibodies by counterimmunoelectrophoresis (CIE) (32 with SLE, 35 with MCTD) were tested for IgG and IgM anti-U1RNP antibodies by enzyme-linked immunosorbent assay (ELISA) using affinity-purified U1snRNP complexes. Results from ELISA were confirmed by RNA precipitation. IgG RNA precipitation of HeLa cellular extracts was performed using the bulk of the IgG fraction removed from each serum after binding to protein A-Sepharose beads. IgM RNA precipitation was carried out on the IgM fraction of the serum bound to protein A-Sepharose-rabbit anti-human IgM immune complexes. RNAs were electrophoresed in 10.5% acrylamide-7 M urea gels and detected with the silver stain. ELISA showed that all sera were positive to IgG anti-U1RNP, while 12 of the 35 MCTD and 21 of the 32 SLE patients possessed IgM anti-U1RNP (P < 0.025). IgM anti-U1RNP reactivity was found during the follow-up in 20% of 44 sera from 17 MCTD patients and 68% of 112 sera from 23 SLE patients (P < 0.0001). IgG from all the sera precipitated U1RNPs. Eight of the MCTD sera also precipitated U2RNPs and 14 of the SLE sera U2 and/or U4/U6, U5 RNPs. IgM from MCTD sera did not precipitate URNPs, while IgM from SLE sera precipitated predominantly U1RNPs. These data suggest that IgM anti-U1RNP antibodies occur predominantly in patients with SLE. The occurrence of IgG anti-U1RNP without IgM is more frequent in MCTD.
抗U1RNP抗体出现在混合性结缔组织病（MCTD）、系统性硬化症（SSc）、系统性红斑狼疮（SLE）以及其他未明确的结缔组织病患者中。为了将抗U1RNP抗体的同种型与疾病诊断（即SLE或MCTD）相关联，通过对流免疫电泳（CIE）检测出抗U1RNP抗体呈阳性的患者（32例SLE患者，35例MCTD患者）的连续血清，使用亲和纯化的U1snRNP复合物通过酶联免疫吸附测定（ELISA）检测IgG和IgM抗U1RNP抗体。ELISA结果通过RNA沉淀得到证实。使用从与蛋白A - 琼脂糖珠结合后每种血清中去除的大部分IgG组分对HeLa细胞提取物进行IgG RNA沉淀。对与蛋白A - 琼脂糖 - 兔抗人IgM免疫复合物结合的血清IgM组分进行IgM RNA沉淀。RNA在10.5%丙烯酰胺 - 7M尿素凝胶中进行电泳并用银染检测。ELISA显示所有血清对IgG抗U1RNP均呈阳性，而35例MCTD患者中的12例和32例SLE患者中的21例具有IgM抗U1RNP（P < 0.025）。在随访期间，在17例MCTD患者的44份血清中的20%以及23例SLE患者的112份血清中的68%发现了IgM抗U1RNP反应性（P < 0.0001）。所有血清的IgG均沉淀出U1RNP。8份MCTD血清还沉淀出U2RNP，14份SLE血清沉淀出U2和/或U4/U6、U5 RNP。MCTD血清的IgM未沉淀出URNP，而SLE血清的IgM主要沉淀出U1RNP。这些数据表明IgM抗U1RNP抗体主要出现在SLE患者中。在MCTD中，无IgM的IgG抗U1RNP的出现更为频繁。
