Background: Intravenous immunoglobulin rapidly decreases serum levels of intercellular antibodies in patients with pemphigus vulgaris. However, little is known about the effects of this therapy on antibodies directed specifically against desmoglein 1 and desmoglein 3 and on the IgG subclasses of these antibodies. This study was conducted to study the effect of intravenous immunoglobulin therapy on serum levels of IgG1 and IgG4 antibodies against desmoglein 1 and desmoglein 3 in patients with pemphigus vulgaris.
Observations: Within 6 to 16 days after initiating a single cycle of intravenous immunoglobulin therapy in 9 patients, a significant decrease in serum levels of IgG4 and IgG1 antibodies against desmoglein 1 and desmoglein 3 occurred in 60% to 100% of the patients, depending on the antibody subclass and specificity. The median decrease in the antibody levels ranged from 34% to 80%. In addition, most patients (n = 6) showed clinical improvement. The decrease in IgG4 antidesmoglein 3 levels seemed to correlate with improvement in disease activity.
Conclusions: Intravenous immunoglobulin therapy rapidly lowers serum levels of IgG1 and IgG4 antidesmoglein 1 and desmoglein 3 antibodies. There seems to be a stronger association between the decrease in IgG4 antidesmoglein 3 levels and improvement in clinical activity than with changes in the other antibody levels, which suggests that IgG4 antibodies have a more important role in mediating pemphigus vulgaris.