Immuno #13

Front 1

Autoimmunity vs auto-immune disease

Back 1

Autoimmunity is benign

auto-immune disease often fatal.

Front 2

What happens if the body loses tolerance?

Back 2

It mounts an abnormal immune attack, either with antibodies or T cells, against a persons own self-tissue antigens.

Front 3

Autoimmunity

Back 3

Characterised by presence of serum antibodies. Normal consequence of aging, inducible by infectious agents or drugs, potentially reversible (disappears when offending agent does)

Front 4

Autoimmune disease

Back 4

Results from activation of self-reactive T and B cells that follow stimulation by genetic or environmental triggers, causing tissue damage.

Front 5

Four factors influencing development of antoimmune disease

Back 5

1. Genetic

2. Viral

3. endocrine - hormone estrogen promotes autoimmune disease, androgens act as immunosuppressive agents.

4. Psychoneuroimmunological - stress and neurochemicals influences immune response.

Front 6

Examples of autoimmune disease

Back 6

Graves disease, multiple sclerosis.

Front 7

Allograft

Back 7

Transplant between genetically different individuals within the same species.

Front 8

Xenografts

Back 8

Grafts between different species. eg heart valve from pig.

Front 9

Allograft rejection

Back 9

Possibility that host will recognise donor tissue as foreign. Triggers host immune system, destroys donor tissue (tissue rejection reaction)

Front 10

Tissue rejection can occur in two different ways

Back 10

1. Foreign MHC class II molecules on graft stimulate host T-helper cells to aid cytotoxic T cells in graft destruction.

2. T-helper cells react to graft and release cytokines, stimulating macrophages to enter and destroy graft.

Front 11

Why do MHC molecules play a dominant role in tissue rejection?

Back 11

Because of their unique association with recognition system of T cells.

Front 12

Overall graft rejection

Back 12

Individual receives allogeneic transplant, tissues initially accepted and vascularised. If antigenic differences at any HC genes, rejection.

Antigen-specific lymphocytes and monocytes invade and the inflammatory response causes destruction of vessels, nutrient deprivation, necrosis.

Front 13

Graft versus Host disease

Back 13

When transplanted tissue contains immuno-competent cells that recognise antigens and attack the host. Immunosuppressed recipient cannot control the response. Common in allogenic bone marrow transplants. Transplanted bone marrow contains mature T cells, attack recipient.

Front 14

How to prevent Graft versus host disease?

Back 14

Deplete bone marrow of mature T cells by immunosuppressive techniques eg drugs that attack T cells, irridation of lymphoid tissue, antibodies against T cell antigens.

Front 15

Results of Graft versus host disease

Back 15

Skin rash

Diarrhea

Hair loss

General weight loss

Death

Front 16

Immunodeficiencies

Back 16

Defect of one or more components of immune system results in failing to recognise and respond to antigens properly. Make one more prone to infection than people with complete and active immune response.

Front 17

Two types of immunodeficiency

Back 17

Primary (congenital)

Secondary (acquired)

Front 18

Acquired immunodeficiency

Back 18

Because of infections or immunosuppressive organisms (chronic mucocutaneous candidiatis) or virus (HIV). When a previously healthy immune system fails.

Front 19

Congenital Immunodeficiencies

Back 19

Are heritable, mainly due to genetic errors on the X chromosome.

Front 20

Acquired immunodeficiency may be due to

Back 20

1. Malnutrition

2. Chronic illness

3. Toxic agents

4. Viral infection

Front 21

Malnutrition

Back 21

Most common cause. Usually in the form of generalised protein-energy malnutrition or lack of specific nutrients eg zinc, iron, vitamin A.Most severly affected: cell mediated immunity and components of innate.

Front 22

Chronic Illness

Back 22

Directly or via malnutrition. eg advanaced TB, cancer, parasitic disease.

Cancers and leukemias result in production of abnormal cells that replace immuno-competent cells in bone marrow, blood and lymph nodes.

Front 23

Toxic Agents

Back 23

Chemotherapy or radiotherapy and exposure to toxins eg industrial accidents or chemical warfare can damage immune cells.

Immunosuppressive drugs eg steroids, cortisone, cyclosporin reduce tissue rejection but increase susceptibility to infection.

Front 24

Viral Infection

Back 24

May cause severe immunodeficiency depending on cell type affected and virus specificity.