Reaction of rectal mucosa of celiac patients to direct contact with gluten

Kinetics of mucosal granulocyte activation after gluten challenge in coeliac disease

OBJECTIVE

To elucidate the dynamics of the rectal inflammatory response to rectal gluten challenge in coeliac disease by measuring inflammatory mediators released by activated neutrophils, eosinophils and mast cells/basophils.

MATERIAL AND METHODS

The release of myeloperoxidase (MPO), eosinophilic cationic protein (ECP) and histamine was measured continuously during the early challenge period (3-6 h after gluten challenge) in coeliac patients (n = 9) and healthy controls (n = 5). A segmental perfusion technique was used to carry out this part of the study. Another method, the mucosal patch technique, was used to enable studies of the late challenge period (5-48 h after gluten challenge) in coeliac patients (n = 10) and healthy controls (n = 15).

RESULTS

During the early challenge period the MPO levels began to increase as early as 3 h after challenge and increased progressively (p < 0.001) during the next 3 h. A decline in MPO levels was seen 15 h after challenge and another phase of increasing levels at 24 h. The MPO values declined 48 h after challenge but still remained significantly increased (p < 0.05). The ECP levels started to increase 4 h after challenge and increased progressively during the next 2 h (p < 0.05). The ECP kinetics during the late challenge period was similar as for MPO but the relative increase in ECP was more modest. No increase in histamine was found except in one patient who had a transient, early increase of histamine (3-5 h after challenge). No signs of inflammatory reaction to gluten were seen in the controls.

CONCLUSIONS

There is a pronounced neutrophil activation in coeliac patients after rectal gluten challenge. This activation is apparent 4 h after challenge and remains for at least 48 h. A more modest eosinophil activation defined by ECP levels starts 1-2 h later and also remains for at least 48 h. The biphasic pattern of MPO and ECP after challenge suggests a biphasic inflammatory reaction.

Colonic histopathology in untreated celiac sprue or refractory sprue: is it lymphocytic colitis or colonic lymphocytosis?

Colonic histopathology in some patients with untreated celiac sprue and refractory sprue has been said to be indistinguishable from lymphocytic colitis, but there have been no objective comparisons on which this is based. The purpose of this study was to determine the prevalence and to characterize the nature of colonic histopathology at the time of diagnosis in patients with celiac or refractory sprue. Colonoscopic biopsy specimens obtained at the time of diagnosis from 16 patients with celiac sprue, six patients with refractory sprue, nine patients with lymphocytic colitis, and five normal controls were analyzed blindly by histological and morphometric methods, quantitating the number and specific subtypes of inflammatory cells within the lamina propria and epithelium. Immunoperoxidase staining of intraepithelial lymphocytes with a monoclonal antibody to CD8 also was performed. Three of 16 patients with untreated celiac sprue (19%) were thought to have colonic histological abnormalities, which by morphometry consisted of slightly increased numbers of lymphocytes in the surface epithelium and lamina propria, many of which were CD8-positive. These abnormalities were distinguishable from lymphocytic colitis by the lack of increased overall lamina propria cellularity and surface epithelial abnormalities, and by fewer intraepithelial lymphocytes. In refractory sprue, colonic histological abnormalities were more frequent than in celiac sprue, occurring in four of six patients (67%), more pronounced, and identical to those in the lymphocytic colitis syndrome. However, colonic intraepithelial lymphocytes in lymphocytic colitis were mostly CD8-positive, whereas those in the colitis of refractory sprue rarely were. Mild colonic lymphocytosis in patients with untreated celiac sprue should be distinguished from lymphocytic colitis by the lack of surface epithelial abnormalities, the lack of increased cellularity of the lamina propria, and the lack of ongoing watery diarrhea after treatment with a gluten-free diet. In contrast, colonic histopathology in refractory sprue is indistinguishable from lymphocytic colitis, although immunohistochemical differences do exist.