Effect of intravenous immunoglobulin therapy on serum levels of IgG1 and IgG4 antidesmoglein 1 and antidesmoglein 3 antibodies in pemphigus vulgaris.

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.