Circulating Th2 memory cells in IgG4-related disease are restricted to a defined subset of subjects with atopy.

IgG4-related disease (IgG4-RD) is characterized by a lymphoplasmacytic infiltrate composed of IgG4(+) plasma cells, tumefactive lesions, obliterative phlebitis, and mild to moderate eosinophilia. It has been suggested that IgG4-RD is characterized by allergic manifestations and is potentially driven by enhanced T-helper type 2 (Th2) responses. We aimed to investigate the potential contribution of atopy to enhanced Th2 responses in IgG4-RD. Peripheral blood mononuclear cells from 39 patients were isolated and subjected to in vitro mitogenic stimulation with PMA and ionomycin. Following stimulation, gated CD3(+) CD4(+) T cells were analyzed for production of the Th2 cytokines IL-4, IL-5, and IL-13. Among the 39 patients analyzed, only the 18 patients who had a history of atopy showed increases in circulating Th2 memory cells. Our results indicate that Th2 responses that have been reported in IgG4-RD may result from concomitant atopic manifestations in disease subjects.