Lately, I've been reviewing a lot of data based on studies of responses to gluten challenges, including studies of responses to low to moderate amounts of gluten in the diet, and in virtually all of these studies, the researchers find it relatively easy to recruit subjects who are asymptomatic, (after many years on the GF diet), and it is easy to find subjects who show negative serology, but it is almost impossible to find subjects who do not show significant histological deviations from normal. IOW, virtually all of them have either some significant degree of villus shortening, or crypt hyperplasia, or elevated intraepithelial lymphocyte count, or a combination of those markers.
When I began to check that out, by researching long-term followup studies, the more recent ones show a rather shocking revelation, (that our doctors never told us about) - namely that true histological remission of damage caused by gluten-sensitivity, is apparently either extremely rare, or non-existent, (for celiacs).
Anyway, the point I'm trying to make is that there appears to be a very good chance, (IMO), that even those of us in remission, are probably only in symptomatic remission, and not in histological remission. Pathology rulings of biopsy samples that indicate "no signs of MC", are probably the result of an incomplete analysis - IOW, only certain markers were considered, (and maybe misjudged), and/or other markers were overlooked. If celiacs cannot attain true histological remission, (with only gluten to worry about), then it's unlikely that we would fare any better.
As to why this is happening - IMO, it's almost surely because of a combination of factors, beginning with the fact that gluten and other problematic ingredients are ubiquitous, and ending with things such as the interaction between retinol and IL-15, (and probably involving one or two other inflammatory diet or supplement issues that haven't yet been discovered). Sooooooooo, it's beginning to appear that the best we can hope for is conditional symptomatic remission, (which, of course, should be good enough for all practical purposes). I had really hoped, though, that the diet could eventually bring total histological remission, as well, but that's beginning to appear very unlikely.
Maybe this is why the disease can never be cured, (and only the clinical symptoms can be controlled).
Tex

Visit the Microscopic Colitis Foundation Website

