Effect of cyclosporin A treatment on the enteropathy of graft-versus-host reaction in the rat: a quantitative study of intestinal morphology, epithelial cell kinetics and mucosal immune activity

Basal secretion and anaphylactic release of rat mast cell protease-II (RMCP-II) from ex vivo perfused rat jejunum: translocation of RMCP-II into the gut lumen and its relation to mucosal histology

The kinetics of the release of rat mast cell protease-II (RMCP-II) from mucosal mast cells in the jejunum of Nippostrongylus brasiliensis primed (immune) rats was investigated using ex vivo perfusion of a segment of jejunum through the cranial mesenteric artery. The aim of the study was to assess the role of the protease in anaphylaxis and in particular to ascertain whether it is responsible for the histological changes, which include widespread epithelial shedding, seen in the mucosa in in vivo models of anaphylaxis. Perfusion of the jejunal vasculature with a Krebs-Ringer buffer showed that there was basal secretion of RMCP-II by jejunal mast cells in all rats studied. The baseline concentration of RMCP-II was significantly greater (p < 0.05) in immune rats (> 7 ng/ml) previously exposed to nippostrongylus infection than in control, naive animals (< 2 ng/ml). Challenge of immune rats with 100 or 400 worm equivalents of whole worm antigen resulted in an immediate (within 40 seconds) and significant (p < 0.02) increase in the concentration of RMCP-II (to > 3 micrograms/ml) in the vascular perfusate, which was not seen in naive rats or immune rats challenged with an irrelevant antigen. Greater amounts of RMCP-II were also recovered from the jejunal lumen of immune rats compared with naive rats after challenge of both groups with worm antigen. Despite the release of microgram quantities of RMCP-II into the gut lumen and vascular perfusate, however, there were no significant changes seen in the mucosal histology. These results suggest that RMCP-II alone is not responsible fore the loss of gut epithelium seen during anaphylaxis in the rat.

Quantitative histological study of enteropathy associated with HIV infection

A quantitative histological study was performed on small intestinal biopsies from eight ambulatory patients with HIV infection (AIDS/AIDS-related complex, ARC) and compared with those from 16 normal subjects. Enteropathy was assessed by measurement of villus area, crypt length and mitotic count, as well as duodenal counts of intraepithelial lymphocytes, mucosal mast cells and goblet cells. Enteropathy in subjects with AIDS/ARC was shown by reduced mean villus area of 0.363 (SD 0.081) compared with 0.500 (SD 0.064) mm2 in control subjects (p less than 0.0001), while intestinal crypts were of similar length with 239 (SD 36) compared with 225 (SD 28 microns, but mitotic count was increased to 3.8 (SD 1.2) compared with 2.4 (SD 0.8) (p = 0.01) in the same control subjects. These results indicate villous atrophy with impaired crypt hyperplasia. Duodenal cell counts showed similar numbers of mucosal mast cells, intraepithelial lymphocytes and goblet cells in AIDS/ARC patients and fifteen control subjects.