More Dumb Questions -- About Villi

[beachbirdie]

As I ponder some of the information I have been reading, I started to wonder...

Can someone tell me what exactly causes the damage to the villi? If the damage is caused by antibodies, how would the villi be damaged in those people who have celiac, but are seronegative?

Is there something else that happens to cause the blunting?

Please don't be too hard on me if this is truly a dumb question.

It seems the more I read about different aspects of celiac, the more complex it becomes!

[Skylark]

Your gut has a tremendous immune system to protect you from bacteria and viruses in your food. It's called the gut-associated lymphoid tissue. Part of that system are cells called intraepithelial lymphocytes that reside in your intestinal epithelium to kill invading bacteria. In a celiac biopsy there will be an abnormal number of these cells. They are recruited to the intestinal epithelium from the lymph and mistakenly directed to kill villi instead of bacteria by anti-TTG and anti-EMA autoantibodies. They can do their job very efficiently and are the cause of villous damage in celiac.

In seronegative celiac, the autoantibodies don't travel out to the bloodstream and are instead confined to the intestines. My understanding is that most of the celiac immune reaction happens in the lamina propria and gut-associated lymphoid tissue and that the antibodies doctors can measure in blood tests are sort of spilling over into the blood.

Enteroviruses like Rotavirus can also cause villous blunting, but it heals pretty quickly after the viral infection. In that case the virus invades the villi and directly damages the delicate cells at the tips. A good GI will reschedule celiac biopsies if the person comes down with a severe diarrheal disease. Giardia infections can also cause villous damage, which is why Giardia is part of the differential diagnosis for celiac disease.

[beachbirdie]

Your gut has a tremendous immune system to protect you from bacteria and viruses in your food. It's called the gut-associated lymphoid tissue. Part of that system are cells called intraepithelial lymphocytes that reside in your intestinal epithelium to kill invading bacteria. In a celiac biopsy there will be an abnormal number of these cells. They are recruited to the intestinal epithelium from the lymph and mistakenly directed to kill villi instead of bacteria by anti-TTG and anti-EMA autoantibodies. They can do their job very efficiently and are the cause of villous damage in celiac.

In seronegative celiac, the autoantibodies don't travel out to the bloodstream and are instead confined to the intestines. My understanding is that most of the celiac immune reaction happens in the lamina propria and gut-associated lymphoid tissue and that the antibodies doctors can measure in blood tests are sort of spilling over into the blood.

Enteroviruses like Rotavirus can also cause villous blunting, but it heals pretty quickly after the viral infection. In that case the virus invades the villi and directly damages the delicate cells at the tips. A good GI will reschedule celiac biopsies if the person comes down with a severe diarrheal disease. Giardia infections can also cause villous damage, which is why Giardia is part of the differential diagnosis for celiac disease.

Thank you so much for that! You have helped me greatly and made it very understandable.