Th17/Treg ratio in human graft-versus-host disease.

Th17 cells have never been explored in human graft-versus-host disease (GVHD). We studied the correlation between the presence of Th17 cells with histologic and clinical parameters. We first analyzed a cohort of 40 patients with GVHD of the gastrointestinal tract. Tumor necrosis factor (TNF), TNF receptors, and Fas expression, and apoptotic cells, CD4(+)IL-17(+) cells (Th17), and CD4(+)Foxp3(+) cells (Treg) were quantified. A Th17/Treg ratio less than 1 correlated both with the clinical diagnosis (P < .001) and more than 2 pathologic grades (P < .001). A Th17/Treg ratio less than 1 also correlated with the intensity of apoptosis of epithelial cells (P = .03), Fas expression in the cellular infiltrate (P = .003), TNF, and TNF receptor expression (P < .001). We then assessed Th17/Treg ratio in 2 other independent cohorts; a second cohort of 30 patients and confirmed that Th17/Treg ratio less than 1 correlated with the pathologic grade of GI GVHD. Finally, 15 patients with skin GVHD and 11 patients with skin rash but without pathologic GVHD were studied. Results in this third cohort of patients with skin disease confirmed those found in patients with GI GVHD. These analyses in 96 patients suggest that Th17/Treg ratio could be a sensitive and specific pathologic in situ biomarker of GVHD.

Donor-derived oral squamous cell carcinoma after allogeneic bone marrow transplantation.

In animal models, tissue stem cells were proposed to exhibit an unexpected level of plasticity, although issues on cell fusions have lead to some controversies. Only transplantation experiments using genetically distinct recipients and donors can unequivocally show these changes in cell fate. We have analyzed oral squamous cell carcinomas arising in 8 long-term survivors of allogeneic bone marrow transplantation, in whom chronic graft-versus-host disease greatly favors development of squamous cell carcinomas, possibly as a consequence of lichenoid mucosal inflammation. With the use of 2 independent methods, (1) combined immunostaining and fluorescent in situ hybridization (FISH) analysis for X and Y chromosomes sequences in sex-mismatched grafts and (2) comparison of microsatellite typing of laser-microdissected tumor, donor, and recipient cells, in all tumors, we showed that 4 of these 8 epithelial tumors actually arose from the engrafted allogeneic bone marrow. Thus, donor-derived bone marrow cells, whether hematopoietic or mesenchymal, recruited to sites of chronic mucosal inflammation yielded epithelial tumors. Our observations therefore show that marrow cells in humans have a major role in epithelial cancer formation after allogeneic transplantation.

Experimental study of the effects of probiotics on Cryptosporidium parvum infection in neonatal rats.

To date, there is no efficient treatment for cryptosporidiosis and parasite eradication relies on innate and acquired immunity. In this study, we investigated the effect of administration of probiotic bacteria on the development and progression of the experimental infection in suckling rats. Rats were fed daily with 2.10(7) CFU of Lactobacillus casei-containing mixture, starting 2 days before the infection until the spontaneous clearance of the parasite. Effects on weight gain, parasite burden, mucosal histology and production of mucosal cytokines (IFNgamma, IL10 and TNFalpha) were studied. Although a trend to a more rapid clearance of parasites was noted in rats treated with probiotics, no significant effect of probiotics administration was observed in terms of weight gain, parasite burden, mucosal damage, or kinetics of mucosal cytokines during the course of infection. Overall, our results showed that the daily administration of L. casei-containing mixtures was unable to eradicate the parasite in our model.