Quantitation of CD4+CXCR5+IL-4+ TFH cells revealed that approximately 67% of CD4+CXCR5+ TFH cells in an IgG4-RD patient expressed IL-4, whereas fewer than 5% of tonsillar CD4+CXCR5+ TFH cells expressed IL-4 (Fig 2B). The gene discussed is IL4; the disease is immunoglobulin G4-related sclerosing disease.