Question

5. A patient comes into your doctor’s office (you specialize in immunology and allergy) with a problem. Every time they get a gastro-intestinal infection, they have a very severe inflamed gut. This doesn’t happen when they get either respiratory or skin infections. When you biopsy the iliac and mesenteric lymph nodes, you don’t find any B or T cells that are responsive to the infection, which is a bit surprising. Based on the role of LN and GALT, explain why the above situation is unusual. Suggest an explanation for what is occurring in this patient, and propose a method for potentially helping them.

Answer 1

ANS: A patient comes into doctor's office with a problem. Every time they get a gastro-intestinal infection, they have a very severe inflamed gut.

but this doesn't happen when they get either respiratory or skin infections.

when biopsy the iliac and mesentric lymph nodes, it didn't find any B or T cells that are responsive to the infection, which is a bit surprising.

Based on the role of LN and GALT, the above situation is unusual because:

LN: Lymph Node GALT: Gut-associated lymphoid tissue.

Because of the gut associated immune system does not allow the harmful intestinal antigens from the systemic circulation and this gut associated immune system induces systemic tolerance against luminal antigens.

Intestinal immune responses against luminal antigens include IgA secretion and induction of regulatory cells.

other cytokines, lymphotoxin regulates the development of intestinal lymphoid organs.

Lymphotoxin signalling involved in the development of mesenteric lymph nodes.

so, intestinal inflammation is supressed by inhibition of lymphotoxin beta signalling.

Antigen containing cells have the balance between intestinal immune tolerance and inflammation.

so, that the gut associated lymphatic organs and factors regulating their development are critical for the prevention of adverse immune reactions to intestinal antigens.

Bacterial antigens of the intestinal flora involved in it. The immune response towards intestinal antigens is non-harmful to the entire organism and it includes induction of systemic immune tolerance and IgA secretion.

The problem and infection starts from the loss of tolerance against intestinal antigens.

so, the inflammation consists of mainly B and T cells throughout the gut wall. so in gastro-intestinal infection, inflammed gut found plus lymph nodes responding with B or T cells. it is not happen in allergy.

But in this case, in respiratory and skin infections, inflammed gut not found any biopsy the iliac and mesenteric lymph nodes. and B and T cells are also not found which is responsible for infection.

Because It's not infection. it is ALLERGY.

Thats why in biopsy, don't find any iliac or mesenteric lumph nodes responsive to infection.

so simply we can say that it's an allergy. not an infection.

so, Patient has some respiratory of skin related allergy.

Methods or testing:

for the skin allergy testing:

prick skin testing, and intradermal skin testing evaluated.

Blood Test:

specific IgE tests are performed for the evaluation of the allergy.

Blood tests are used to evaluate certain disorders of the immune system and allergy.

Spirometry ( Lung Function Tests):

Spirometry is a type of lung function test that we can use to evaluate allergy in respiratory tract like ashtma.

During this test, we have to ask the patient for inhale and exhale deeply and forcefully accordingly. and by the device we can meaures the lung function.

Food allergy:

Food challenges are the test performed to confirm a food allergy.

in this we can measure the dose or quantity of food that are given to patient by a specific period and specific dose and assessment can be done accordingly. we can observe the reactions. due to the risk of developing an adverse reaction, all food challenges are performed under physician supervision.

Drug/Medicine allergy:

that also can be happen so drug/medicine challenges are performed as same as food allergy.

Patch testing:

this test is used for the evaluation of skin allergy like dermatitis.

So, these are some allergy testing that can help in this situation.