The
IgG,
IgA and
IgM classes of circulating
immune complexes (CIC) were examined in 49 patients with
systemic lupus erythematosus (SLE). The presence of the
IgG class of CIC (
IgG-IC),
IgA class of CIC (
IgA-IC) and
IgM class of CIC (
IgM-IC) was observed in 39.4%, 24.2% and 35.3%, respectively. During the course of the disease, the levels of
IgG-IC and
IgM-IC remained generally higher than that of
IgA-IC. The patients were divided into three groups, according to the changes in
IgG-IC. Group 1: these had
IgG-IC persistently, associated with clinically active features (active stage). The presence of
IgA-IC was occasionally transient, although
IgM-IC did coexist. Group 2: these showed an increased level of
IgG-IC, associated with a tendency to relapse (flaring up stage).
IgM-IC disappeared occasionally, although
IgA-IC appeared to be persistently present. Group 3: these showed levels of
IgG-IC which decreased or disappeared and the clinical activity tended to subside (remissible and inactive stages). All classes of CIC tended to disappear. That is to say,
IgG-IC, then
IgA-IC, and finally
IgM-IC decreased in that order. Either
IgA-IC or
IgM-IC was present alone persistently in a few cases. The correlations between each class of CIC and the immunological parameters were investigated.
IgG-IC and
IgM-IC were closely related to anti-nuclear antibody, but not to anti-
DNA antibody.(ABSTRACT TRUNCATED AT 250 WORDS)