TNFSF13B and disorder of appendix: To the best of our knowledge, up to now there are only 4 cases that describe appendiceal disease associated with increased IgG4 plasma cells.[5–8] The pathophysiology of IgG4-RD remains poorly understood; however, type 2 T-helper cell, which regulates T cell cytokines, and B cell activating factor, have been suggested to be associated with the development of the disease.[9]