Zeng Y, et al. - This study was intended to evaluate the distribution of anti-nuclear antibody (ANA) IgG subclasses in patients with systemic lupus erythematosus (SLE) and to explore their influence on the inflammatory process in SLE. The serum levels of ANA IgG subclasses were determined from 70 SLE patients, 25 patients with other autoimmune diseases, and 25 healthy controls using ELISA. Via ELISA, the serum level of total ANA IgG and the avidity of ANA IgG, dsDNA IgG, and dsDNA IgG subclasses were examined. The data indicated that the ANA IgG subclasses were diagnostic tools. Moreover, HA IgG ANAs might influence the distribution of ANA IgG3 and IgG4. The outcomes suggested that ANA IgG3 might play a particular role in the activity of SLE disease and therapy. Thus, in SLE, an altered ANA IgG subclass distribution might be a risk factor influencing the inflammatory process.