Classification of Chronic Obstructive Pulmonary Disease and Inflammatory Bowel Disease: TH1- and TH22-Dominant Autoimmune Disorders

Chronic obstructive pulmonary disease (COPD) and inflammatory bowel disease (IBD) are heterogeneous inflammatory disorders. COPD can be classified into emphysema and chronic bronchitis, whereas IBD can be classified into Crohn’s disease and ulcerative colitis. We hypothesize that COPD, like IBD, is also an autoimmune disease. However, the detailed immunopathogenesis of these diseases remains unclear. In this review, we summarize experimental, epidemiological, and clinical evidence linking autoimmunity to these disorders. Emphysema and Crohn’s disease are proposed to be TH1-dominant autoimmune disorders, whereas chronic bronchitis and ulcerative colitis are proposed to be TH22-dominant autoimmune disorders. A more detailed understanding of the immunopathogenesis of these diseases may support more specific and effective therapeutic strategies.