However, no significant difference was found in the CCR1 and CX3CR1 expression in 3 MN subsets between IgG4-RD and HCs, except that CX3CR1 expression was lower in IgG4-RD CMs compared with HC CMs (Supplemental Figure 5D). Here, CX3CR1 is linked to immunoglobulin G4-related sclerosing disease.