IGHE and immunoglobulin G4-related sclerosing disease: An allergen-specific IgE response was identified in 52% (25 of 48) of IgG4-RD patients and 40% (19 of 48) of IgG4-RD patients were defined as “atopic.” An elevated serum IgE level was present in 53% of IgG4-RD patients with atopy.