抗细胞膜DNA抗体的测定及其在系统性红斑狼疮诊断中的意义

Significance of anti-cell membrane associated DNA (mDNA) antibodies in systemic lupus erythematosus

目的建立抗细胞膜DNA(m DNA)抗体测定的方法,研究其在系统性红斑狼疮(SLE)诊断中的敏感性和特异性,以及与SLE临床特点及免疫学异常的关系。方法检测SLE患者、疾病对照组和正常对照组血清中的抗m D NA抗体,并分析SLE患者的各种临床表现及实验室指标与抗m DNA抗体的关系。同时研究细胞膜DNA分子在不同细胞表面的表达,用DN A酶、RNA酶及胰酶鉴定抗原性质。结果抗m DN A抗体在SLE中检测敏感性73.3%(152/207),特异性96.4%,疾病对照组阳性率5.4%(9/167),82名正常对照组均为阴性,抗m DN A抗体阳性率在SLE组明显高于疾病对照组和正常对照组(P<0.01)。抗m DN A抗体在其他自身抗体阴性的SLE患者中有较高的检出率,在抗双链D NA(dsDN A)抗体、抗Sm抗体、快速狼疮因子(DNP)、抗组蛋白抗体(AH A)、抗核小体抗体(AnuA)阴性的SLE患者中抗m DNA抗体的阳性率分别是73.8%、62.7%、65.3%、57.8%和51.6%。该抗体阳性组SLE患者皮疹,脱发,关节痛,白细胞和C3、C4减低及IgG、IgA、IgM升高较为常见,但与SLE患者病情活动指数无关。本文还证实细胞膜DNA在人B细胞、T细胞上均有表达,以R aji细胞株表达较好。用D NA酶预处理的细胞涂片再行检测后膜荧光图形消失,而用RN A酶、胰酶预处理后并不消失,证实其为膜D NA抗原。结论抗m DN

Objective To establish the method of anti-cell membrane associated DNA (mDNA) antibody detection, to evalute its sensitivity and specificity in systemic lupus erythematosus (SLE), and to analyze the relationship between anti-mDNA antibody and the clinical features of SLE. Methods Indirect immunofluorescence assay was used to measure anti-mDNA antibodies in sera of 207 SLE patients, 167 patients with other rheumatic diseases and 82 healthy controls. Using indirect immunofluorescence to detect the expression of mDNA with positive standard serum samples on nine cultured cell lines and pre-treated cells by DNAse, RNAse or trypsin. Results Of the serum samples, 73.3% SLE and 5.4% other rheumatic diseases were positive for anti-mDNA, but negative in 82 blood donors (P<0.01). The sensitivity and specificity of anti-mDNA were 73.3% and 96.4% respectively. The frequency of anti-mDNA antibody in SLE patients with negative anti-dsDNA, Sm, anti-deoxyribonucleoprotein antibody (DNP), anti-histone antibody (AHA) and anti-nucleosome antibody (AnuA) was 73.8%, 62.7%, 65.3%, 57.8% and 51.6% respectively. The incidences of skin rash,alopecia, joint pain, low levels of WBC, C3 and C4, IgG, IgA and IgM elevation were more common in anti-mDNA antibody positive SLE than those of anti-mDNA antibody negative SLE, but there was no significant difference in SLEDAI between anti-mDNA antibody positive and negative SLE patients(P>0.05). This study also proved that mDNA was expressed on B and T lymphocytes, the strongest staining was expressed on Raji cell line. The mDNA molecule was confirmed by pattern extinction on the cells pre-treated with DNAse but not RNAse or trypsin. Conclusion Anti-mDNA antibody is one of the most valuable marker in the diagnosis of SLE. Anti-mDNA antibody is valuable in diagnosis of SLE with negative anti-dsDNA, Sm, DNP, AHA and AnuA antibodies; but it has no significant with relationship the disease activity of SLE.