\ We detected the antinucelear antibody

double string DNA and C 3 in 45 patients with systemic lapus erythematosus(SLE)by fluorescent immunoassay (FIA) and single immue diffsion test. All of them were positive in antinuclear antibody (ANA).Classifical by Hep-2 cell dyeing andlysis

21 patients were in speckled type

17 patients in homogenous tye

2 patients in peripheral type and 5 patients in speckld homogenous mixture type.Among the 45 patients

22 of them were positive in double string DNA and the others were negative.The C 3 concentrations of patients with double-string DNA positive and negative were 0.499±0.143(g/L) AND 0.715±0.217(g/L) respectively.It is suggested that postive double-string DNA and enduced C 3 concentration mean that the patients with SLE were in active period;negtive double-string DNA and recovery of C 3 concentation suggest that the SLE patients were in remission.Thus

it is of clinical value to measure double-string DNA and C 3 in obsering the clinial course of SLE and in directing its treatment.\ \