High-dose Intravenous Immunoglobulin Treatment Increases Regulatory T Cells in Patients with Eosinophilic Granulomatosis with Polyangiitis

Objective: We studied the effects of intravenous immunoglobulin (IVIG) treatment on clinical symptoms and regulatory T (Treg) cell frequency in patients with eosinophilic granulomatosis with polyangiitis (EGPA).

Methods: Twenty-two EGPA patients with severe mononeuritis multiplex or cardiac dysfunction received IVIG therapy combined with conventional therapy (corticosteroid, immunosuppressants, or both). As a control, 24 EGPA patients without severe vasculitic symptoms were treated with conventional therapy. Before, during, and after treatment, we determined percentages of Treg cells and other relevant cells in patients' peripheral blood.

Results: The frequency of CD25+ among CD4+ T cells was lower at onset in the study group than in controls but increased significantly after IVIG treatment, relative to controls. The frequency of CD25+ among CD4+ T cells correlated with the frequency of FOXP3+ among CD4+ T cells and interleukin 10 produced by CD25+CD4+ T cells.

Conclusion: The increase in Treg cells seen with the combination of IVIG and conventional therapy may promote remission in EGPA.