Abstract
The levels of IgG subclasses were determined in patients with active systemic lupus erythematosus (SLE). The levels of all IgG subclasses in these patients were higher than normal controls. However, there were variations in the increase of IgG subclasses, especially IgG 1 or IgG 2. As concerning the relation to the clinical findings, the levels of IgG 1 significantly increased in patients with renal involvements and those of IgG 3 increased in patients with low complements. Thus, it was suggested that some IgG subclass related to some clinical findings.