Moreover, MFI of BAFF-R in CD19+ B cells from IgG4-RD patients was lower than in HC (243.9 ± 149.35 and 430.56 ± 109.28, respectively; P <0.001), but was similar to that in pSS patients (323.5 ± 96.46; P >0.05). Here, CD19 is linked to peeling skin syndrome.