系統性紅斑狼瘡病人其抗雙縷去氧核醣核酸抗體結合第三補體成分能力之臨床意義

Clinical Significance of Complement (C3)- Fixing Activity of Anti- ds DNA Antibodies in Patients with Systemic Lupus Erythematosus

連續收集42位以血鞭毛蟲Crithidia luciliac免疫螢光法檢查帶有抗雙縷去氧核醣核酸抗體(anti- ds DNA)陽性之系統性紅斑狼瘡病人，分成四群：第一群20位是活動期有腎炎病人；第二群13位是活動期無腎炎病人；第三群7位是非活動期有腎炎病人以及第四群2位是非活動期無腎炎的病人。全部再以同法分別檢查anti- ds DNA之IgG、IgA和IgM屬抗體以及anti- ds DNA結合第三補體成分(C3)之能力(C F- anti- ds DNA)。結果：(1)活動期病人之C F- anti- ds DNA陽性率是48.5％(16／33)，非活動期病人是11.1％(1／9)，其差別有統計學意義(p< 0.05)。(2)活動期病人當中，無腎炎者之C F anti- ds DNA陽性率是46.2％(6／13)，有腎炎者是50.0％(10／20)，兩者差別無統計學意義(0.9< p< 0.95)。(3)IgG、IgA和IgM三屬俱全之anti- ds DNA，其C F-anti- ds DNA之陽性率要比單獨只有IgG屬之anti- ds DNA者高(p< 0.05)。(4) Anti-ds DNA之結合C3能力與anti- ds DNA之總濃度成有意義之關連(r= 0.71，p< 0.01)。由以上結果顯示anti- ds DNA之結合C3能力與狼瘡腎炎並無有意義之關連，而與狼瘡病人之活動度有關。

To investigate the suggestion that complement- fixing activity of anti- ds DNA may play an important role in the pathogenesis of nephritis in systemic lupus erythematosus (SLE), we used the Crithidia lucilia (CL) immunofluorescence test to determine the titre, immunoglobulin (Ig) class and complement (C3)-fixing (CF) activity of anti-ds DNA in 42 patients with SLE. All patients had anti- ds DNA as a criterion for inclusion into this study. Twenty of these patients had active lupus nephritis, 13 had active SLE without nephritis, and 9 had inactive SLE. CF activity was detected in 16 of 23 patients with active SLE and 1 of 9 patients with inactive SLE, The difference was statistically significant (p< 0.05). In active patients, CF activity was detected in 10 of 20 with nephritis and 6 of 13 without nephritis. The difference between these two groups was insignificant (0.9< p <0.95). Anti- ds DNA with all three Ig classes was found to have CF activities more frequently (p< 0.05) than did that with IgG only. The relationship between anti- ds DNA titre and CF activity was found to be significant (p< 0.01). These findings suggest that CF activity of anti- ds DNA correlates with the disease activity of SLE but not with the occurrence of nephritis.