The occurrence of anti-double stranded (ds) DNA idiotype 2C10 was studied in patients with mixed connective tissue disease (MCTD) and progressive systemic sclerosis (PSS). The 2Cl0-idiotype was originally identified on a dsDNA-specific monoclonal antibody from a lupus-prone MRL/Mplpr/lpr (MRL/I) mouse, and it has been demonstrated to be present in the sera of patients with systemic lupus erythematosus (SLE) as well as MRL/I mice. This study showed that three out of ten patients with MCTD and five out of ten with PSS had higher titers of 2C10-idiotype in their sera than the normal subjects. There was a good correlation between the anti-dsDNA activities and the idiotype levels in MCTD (r=0.85) but not in PSS (r=-0.38). These results suggest that the 2C10-idiotype-bearing antibodies acquire the dsDNA-binding activity more easily in MCTD than in PSS.
Plasma levels of fibrinopeptide A (FPA), brinopeptide B,β15-42 (FPB,β15-42), high molecular weight kininogen (HMW-kg), kinin, prekallikrein and kallikrein inhibitor during pregnancy, labor, cesarean section and puerperium were studied in 170 cases of full term normal delivery and 20 cases of cesarean section delivery with 30 non-pregnant women taken as control. Significant increases of FPA, FPBβ 15-42 and kinin during normal delivery and puerperium were found. There was also a significant increase of FPA in the uterine venous blood during cesarean section. Significant decrease of HMW-kg during normal labor and also significant decrease of prekallikrein and kallikrein inhibitor after cesarean section were also seen. Our findings suggested that the hypercoagulable state during pregnancy is due to the increase of thrombin and plasmin activity, and the kallikrein-kinin system may be related to the onset of labor and post-delivery uterine contraction. Increase of the FPA in the uterine blood promoted localised coagulation activity during cesarean section.