How can two different sources cause the same immune response?

[DrHouse]

I've been pondering on this for a while to no avail; google searches/immunology textbooks have also failed me.

 

So to best explain this, lets use something popular like gluten.

 

Gluten is known to cause auto-immune reactions. Makes sense due to genetic factors. However,it has no relationship to something like hair follicles, then how can gluten elicit an auto-immune response towards the hair follicles, causing hair thinning? Despite the fact that it has no relation to it?

 

Would it be that the antigens of gluten and the hair follicle antigen share similar homology in their peptide structure? This would lead to the same response since the body is unable to distinguish the two responses.

 

Or is the body eliciting one response, which is towards gluten, which results in an auto-immune response, which carries the antibodies and cells towards the hair follicles through the blood stream and thus causes the same response? This would mean that the cells involved in the auto immune response are not specific to just the intestinal tract?

 

Any ideas?

 

Thanks.

[fiveworlds]

Hair loss is another sign that thyroid hormones may be out of balance. Both hypothyroidism and hyperthyroidism can cause hair to fall out. In most cases, the hair will grow back once the thyroid disorder is treated. WEBMD

 

 

Hypothyroidism and Hyperthyroidism both mess with the body's normal metabolism. Celiac disease also messes with the body's normal metabolism. Perhaps they have an effect on the absorption of chemicals required for healthy hair growth??

Edited July 20, 2016 by fiveworlds

[DrHouse]

 

Hypothyroidism and Hyperthyroidism both mess with the body's normal metabolism. Celiac disease also messes with the body's normal metabolism. Perhaps they have an effect on the absorption of chemicals required for healthy hair growth??

 

Thanks for your reply, Fiveworlds.

 

I see your perspective on relating metabolic processes but simply put, if patient X has adverse reactions to gluten, perhaps not at the level of a celiac, but nevertheless adverse, and patient X also has a history of Alopecia Areata, then how is gluten causing the patchy hairloss?

 

My current theory is this, and please correct me if you think this is inaccurate:

 

The gluten antigen is similar in homology in its protein sequence to the antigen that causes Alopecia Areata. The resultant would be the body responding to one signal, in two ways; people that do not have issues with gluten can still have Alopecia Areata because of the antigen but would not have the characteristics of a celiac.

 

My other theory is simply that the adverse reaction to gluten results in destruction of vital cells in the intestines that would normally be involved in nutrient absorption that are critical to hair, such as biotin; this theory would make sense but alopecia areata is an autoimmune condition, making it a bit difficult since the autoimmune response would be in response to a specific trigger, not the lack of nutrients.

 

My last theory is what you had mentioned, metabolic processes. However, based off of theory 2, this does not make sense because alopecia areata is autoimmune. In essence, we have two autoimmune diseases and they may have a common cause: gluten. If this is so, why is gluten causing two autoimmune reactions? Is it because the antigens share homology and thus activate both autoimmune disease pathways OR is it because the gluten antigen simply activates two pathways (which wouldn't make sense unless the antigen sequence was similar among the two completely separate diseases)?

 

I've been pondering this for a while and must find the source!