Notably, the KEGG results showed that most of the genes co-expressed with RAB42 were involved in immune-related diseases, including allograft rejection, autoimmune thyroid disease and graft-versus-host disease, and immune-related processes, such as T cell/B cell receptor signaling pathway, Th1 and Th2 cell differentiation and natural killer cells mediated cytotoxicity. The gene discussed is RAB42; the disease is graft versus host disease.