In experimental models, proinflammatory cytokines such as TNFa have been implicated in altered GI function caused by Cryplosporidium. To test the role of cytokines in pathogenesis of human cryptosporidiosis, 8 normal volunteers experimentally challenged with C, parvum oocysts and 1 patient with AIDS and chronic cryptosporidiosis underwent small bowel enteroscopy with biopsy of the jejunum. Biopsy specimens were probed with [35S]-labeled cRNA probes for TNFa mRNA. Controls included sense-strand (negative control) and G3PDH (positive control) probes. In the normal volunteers oocyst excretion was first detected 4-9 d postchallenge and lasted until day 10-16. Symptoms occurred near the time of oocyst excretion. One of 2 patients with biopsies prior to challenge had a few cells with TNFa mRNA. Post-challenge, 1 biopsy was negative at day 7 and 2 were weakly positive at day 8. The biopsies with the largest portion of cells with TNFa mRNA were obtained on days 13,19,22, and 22 post-challenge (subsequent to the resolution of symptoms and oocyst excretion). One biopsy on day 30 was weakly positive and 2 on day 33 were negative. TNFa mRNA was detected in both symptomatic and asymptomatic volunteers as well as in the patient with, AIDS and chronic diarrhea. Although TNFa mRNA is present in the small intestine during cryptosporidiosis, peak expression occurs after resolution of diarrhea and in asymptomatic patients. These results suggest that TNFa is not the primary cause of diarrhea in cryptosporidiosis at least in normal hosts.
|Original language||English (US)|
|Journal||Journal of Investigative Medicine|
|State||Published - 1996|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)