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Graft vs Host reaction


OVERVIEW OF Graft vs Host reaction :

Graft-versus-host disease (GVHD) is an immune condition that occurs after transplant procedures when immune cells from the donor (known as the graft or graft cells) attack the recipient patient host's tissues

Graft vs host reaction occurs due to hyperactivity of the immune system. The individuals immune system starts to fight against its own cell resulting in autoimmune disease.


CAUSES :

GVHD is the result of a series of complex interactions between the immune cells of the donor (the graft) and the host tissues; the disease is most likely to occur after a transplantation procedure when donor and recipient tissues are not genetically similar. A number of cytokines and other immune signaling compounds are believed to be important in the development of the condition.


PATHOPHYSIOLOGY :

The immune system of the body mainly focus on the body’s two subsets of T-lymphocytes, known as T helper cells TH1 and TH2. In the normal immune response, TH1 cells releases the mediators which aids the body to defend against invasion from parasites, bacteria and viruses.

In graft vs host reaction, TH2 cells and their mediators encourage the immune system to recognise allergens as an invader, and produce a response against the foreign bodies.Some states that the people living in sterile environment free of exposure to antigen develops reduced immune response to fight against them.

For an autoimmune disorder to take place,the allergen must be come into contact with the body.. Antigen-presenting CELLS SUCH as the macrophages and dentritic cells which are present in the mucosal surface of the cells sensitize the antigen.. the triggering factors enters into the immune system in many ways such as through inhalation,through skin contact, and antigen presenting cells sensitize these allergens and provoke an immune response and this allergen is processed and displayed on the surface of the antigen presenting cells. These cells then migrate to the T lymphocytes and presents the antigen to them which in turn activates B cells to secerete IgE antibodies. This IgE antibodies which is specific to the allergen comes into contact with mast cells on the mucosal surface and basophils on the blood.

After the period of sensitisation described above there is a period of latency, and on subsequent re-exposure to the allergen the allergic response is triggered: allergen cross-links with the IgE on the surfaces of the mast cell or basophil, causing the cell to ‘degranulate’ or release inflammatory mediators. These include largely histamine and other mediators, including cysteinyl leukotrienes, prostaglandins and kinins. They have different actions in terms of symptoms in different organs


COMMON CLINICAL SIGNS AND SYMPTOMS :

Acute GVHD usually happens within days or as late as 6 months after a transplant. The immune system, skin, liver, and intestines are mainly affected. Common acute symptoms include:

  • Abdominal pain or cramps, nausea, vomiting, and diarrhea
  • Jaundice – yellowish colouring of the skin
  • Skin rashes- redness and inflamed area in the skin
  • Increased risk for infections

Chronic GVHD usually starts more than 3 months after a transplant, and can last a lifetime. Chronic symptoms may include:

  • Xerophthalmia which is termed as dry eyes burning sensation, or vision changes
  • Dry mouth, white patches inside the mouth, and sensitivity to spicy foods
  • Fatigue, muscle weakness, and chronic pain
  • Joint pain or stiffness
  • Skin rash with raised, discolored areas, as well as skin tightening or thickening
  • Shortness of breath due to lung damage
  • Vaginal dryness
  • Weight loss
  • Reduced bile flow from the liver
  • Brittle hair and premature graying
  • Damage to sweat glands
  • Cytopenia (decrease in number of mature blood cells)
  • Pericarditis swelling in the membrane surrounding the heart; causes chest pain)

 

Signs:

Swollen glands

Eczema

Alopecia areta(small coin sized area in the region of hair loss

Digestive problems

Prolong soreness of the skin


DIAGNOSTIC :

CT scan: is shows the 3D images of the liver

MRI(magnetic resonance imaging):

It uses magnetic and radiofrequency waves to view the soft tissues. It alos used to reveal the metastasis of the cancer cells.

Biopsy:

 The removal of tissue for study under a microscope. It may be done using a laparoscope. A biopsy is the most reliable way to determine cancer.

Capsule Endoscopy:

 A camera in a capsule (capsule endoscopy). This capsule includes one or two tiny cameras, a light bulb, a battery, and a radio transmitter.

It is about the size of a large vitamin pill. The person swallows the capsule, and it takes pictures all the way through the digestive (gastrointestinal) tract.

Antinuclear antibody:

It is an disease use to identify certain types of proteins.the protein produced  are against the own tissue in autoimmune diseases. them.

Complete blood count:

it looks  after the total red blood cell count,white blood cell,haematocrit,platelets ,hemoglobin level.For example in leucopenia the white blood cell count is decreased.

Complement

A test used to measure levels of a protein group of the immune system called complement within blood. If complement is found in low levels, this may be an indication of disease.

C reactive protein

C reactive protein, a protein made in the liver generally increases with inflammation, and may be high in autoimmune disease.

Erythrocyte sedimentation rate:

This test measures the rate at which a patient's blood cells descend in a test tube. More rapid descents may indicate inflammation, a common symptom of autoimmune disease.

If these tests are indicative antibody abnormalities and inflammation, further tests will be conducted to identify the autoimmune disease present.


TREATMENT AND PROGNOSIS :

Corticosteroids and oral histamines

Tacrolimus for the initial therpay.

Antithymocyte globulin, pentostatin is the major immunosupressor

Adrenaline-Anaphylactic reactions

Immunotherapy-it is indicated in patients who couldnt able to control the allergic reactions.

Vitamins or hormones which replaces the supplememts for the body which is lacking in the persons.

Blood transfusion if the disease is blood related


PREVENTION :

Screening the organ that is undergoing transplantation .

make the body to fight against the diseases and improves the immune function of the body.

stay away from the allergen