MPO and rheumatic disorder: In the autoimmune patient group, there were significant differences in antibody titers against 12 autoantigens, among which Jo-1, SSB, PL-12, PM/Scl100, Scl-70, TIF1γ, and MPO were associated with rheumatic diseases [42], TTG was associated with intestinal inflammatory diseases [43], and AQP4 was associated with demyelinating diseases [44].