Arguments for and against a Mycobacterium avium subspecies paratuberculosis (MAP) causation of Crohn’s disease
| MAP, Mycobacterium avium subspecies paratuberculosis; PCR, polymerase chain reaction; FISH, fluorescent in situ hybridisation; HIV, human immunodeficiency virus. |
| Pros |
| (1) Clinical and pathological similarities between Johne’s and Crohn’s diseases3,4 |
| (2) Presence in food chain (milk, meat) and water supplies7,8 |
| (3) Increased detection of MAP in Crohn’s disease tissues by culture, PCR, FISH5,6,33 |
| (4) Positive blood cultures of MAP in Crohn’s disease patients11 |
| (5) Increased serological responses to MAP in Crohn’s disease patients20,34 |
| (6) Detection of MAP in human breast milk by culture and PCR9 |
| (7) Progression of cervical lymphadenopathy to distal ileitis in a patient with MAP infection35 |
| (8) Therapeutic responses to combination antituberculosis therapy that include macrolide antibiotics10,24 |
| Cons |
| (1) Differences in clinical and pathological responses in Johne’s and Crohn’s diseases4 |
| (2) Lack of epidemiological support of transmissible infection36 |
| (3) No evidence of transmission to humans in contact with animals infected with MAP |
| (4) Genotypes of Crohn’s disease and bovine MAP isolates not similar18 |
| (5) Variability in detection of MAP by PCR (0–100% in Crohn’s disease and ulcerative colitis tissues)8 and serological testing37 |
| (6) No evidence of mycobacterial cell wall by histochemical staining |
| (7) No worsening of Crohn’s disease with immunosuppressive agents or HIV infection |
| (8) No documented cell mediated immune responses to MAP in patients with Crohn’s disease20 |
| (9) No therapeutic response to traditional antimycobacterial antibiotics23 |