A1BG and irritable bowel syndrome: Increasing evidences show that anti-Saccharomyces cerevisiae antibodies (ASCA), anti-neutrophil cytoplasmic antibodies (ANCA), anti-intestinal goblet cell antibodies (GAB), and antibodies to exocrine pancreas (PAB) play a role in assisting diagnosis of IBD, especially in differential diagnosis of UC and CD [6, 7].