Researchers in Iran published a novel study comparing the rates of MAP detection by IS900 PCR, the nature of the intestinal pathology, and the ability to detect MAP by acid-fast staining among 30 humans with Crohn’s disease (CD), 30 humans with non-inflammatory bowel disease (nIBD), 30 goats with clinical signs compatible with Johne’s disease (JD) and 30 healthy goat kids. For the human subjects, they reported that 47% of CD patients and 13% of nIBD controls were IS900 PCR-positive for MAP. By contrast, 70% of JD goats and 0% of healthy goats were IS900 PCR-positive. Acid-fast bacteria (AFB) were seen in tissues of 7% of CD cases. In these cases the number of AFB was characterized as paucibacillary, meaning very few red-staining bacteria were seen. Excellent photomicrographs are provided in the publication. By contrast AFB were seen in 0% nIBD controls, 90% of goat JD cases and 0% of healthy goat controls.
Special to this publication is a table contrasting the types of pathology seen in CD and JD. Pathology common to both the CD patients and JD goats, respectively was: lymphangiectasia/edema (67% vs 96%), vasculitis/lymphangitis (20% vs 73%), diffuse granulomatous enteritis (20% vs 33%), focal or multifocal granulomatous enteritis (63% vs 14%), neuritis or neuronal hyperplasia (36% vs 43%) and cryptitis (40% vs 14%). Pathology unique to JD goats (seen in 0% of CD patients) was: Diffuse multibacillary (abundant AFB) granulomatous enteritis (see in 43% of goats). Pathology unique to CD patients (seen in 0% of goats) was: Ulceration (73%), fibrosis (30%), pyloric gland metaplasia (40%), thrombosis (30%), paneth cell metaplasia/hyperplasia (17%) and goblet cell hyperplasia (14%).
Comment: Readers interested in comparative pathology of CD and JD will appreciate the discussion section of this publication. When considering pathology comparisons between CD and JD, readers should remember: 1) that CD patients generally have undergone prolonged therapy with a wide array of immunosuppressive drugs which may affect the nature of the pathology, while animals are not so treated, and 2) that zoonotic infections seldom cause identical pathology in the animal and human hosts. The duration on therapy for CD patients in this study was not reported but the mean age was 34 years so one could surmise that the patients had their disease for some time before the pathological assessment.
The full Open Access article is available: F. Zarei-Kordshouli, B Geramizadeh, and A. Khodakaram-Tafti. 2019. Prevalence of Mycobacterium avium subspecies paratuberculosis IS 900 DNA in biopsy tissues from patients with Crohn’s disease: histopathological and molecular comparison with Johne’s disease in Fars province of Iran. BMC Infectious DIseases 19:23. doi.org/10.1186/s12879-018-3619-2