NPPB and Autoimmunity: Stool routine, urea nitrogen, creatinine, C-reactive protein (CRP), liver function, serum vitamin B12, IgG4, folic acid, hepatitis virus (A, B, C, D, E), tumor markers (CA125, CA199, CEA, AFP, PSA), brain natriuretic peptide (BNP), and tuberculosis detection (PPD test, T-spot), as well as other autoimmunity makers containing antinuclear antibody (ANA), anti-neutrophil cytoplasmic antibodies (ANCA), and rheumatoid factors were all unremarkable.