Human Leukocyte Antigen Test Helps Identify Genetic Markers For Diseases

November 12, 2012

Human Leukocyte Antigen Test Helps Identify Genetic Markers For Diseases

The human leukocyte test is a necessary part to identify compatible organ donor and recipients but it’s also used to determine the paternity of a child.

Doctors who perform the human leukocyte antigen test (or HLA, for short) are looking to genetic markers on white blood cells. Now, there are four kinds of HLAs:

  • HLA-A

  • HLA-B

  • HLA-C

  • HLA-D

Reason Behind The Test

This HLA test is give doctors evidence of tissue compatibility when typing for tissue recipients and donors. It’s also used for paternity testing and genetic counseling.

What To Consider Before Doing The HLA Test

If a patient has recently done a transfusion, the human leukocyte should be postponed.

Human Leukocyte Antigen: What Is It?

Leukocyte is the actual name for white blood cell; antigen means a genetic marker. And, human leukocyte antigen is the substance found on white blood cells’ surface but it plays an integral part in how the body responds to threats.

And, since the human leukocyte antigen is so important to immunity, identity aids are used to determine the degree of tissue compatibility between transplant donors and recipients. Testing is completed to ensure there is no chance of rejection after a transplant has been done, avoiding the possibility of a graft-versus host disease that can occur after a bone marrow or major organ transplant. It needs to be noted that GVHD can still occur when the recipient and donor have major antigens. For instance, recently there was an HA-1 mismatch because of GVHD in bone marrow grafts from HLA-identical donors.

HLA can help in the paternity exclusion test, which is a very specialized area in forensic medicine. Where paternity is disputed and must be resolved, a man who shows that a phenotype with no an antigen or haplotype identical to the child’s can be excluded as being the father. A man who has one haplotype is identical to the child’s could be the father. Due to the complexity of this testing, experts usually deal with it.

There are certain kinds of human leukocyte antigen have been connected to a number of diseases like:

- Multiple sclerosis

- Rheumatoid arthritis

- Serum lupus erythematosus

- Autoimmune disorders

When separate, none of these human leukocyte antigen types are seen as conclusive. Since the clinical importance of a number of marker antigens is not yet defined, more specific tests to diagnosis the disease are used.

Preparing For The Human Leukocyte Antigen Test

The HLA test will need a blood sample. And, there’s no reason for a patient to fast before the test is administered. Fasting means nothing to drink or eat.

The Risks Behind The Human Leukocyte Antigen Test

The risks for the human leukocyte antigen test are minute but the following things can occur:

  • Slight bleeding at the site where blood was drain

  • Hematoma (accumulation of blood under puncture site

  • Lightheadedness

  • Fainting

What Happens If The Human Leukocyte Results Are Abnormal

If the organ donors and recipients are not compatible, it can cause a failed tissue transplantation.

Now, there are certain diseases with a strong connection to certain kinds of human leukocyte antigens, which could involve genetic counseling. For instance, Hashimoto’s thyroiditis is an autoimmune disorder that means the thyroid gland is not producing enough of the hormone. It’s linked to HLA-DR5. Dw3 and B8 are linked to Graves’ disease and has an overproduction of the thyroid hormone.

Hereditary hemochromatosis, which means there’s too much iron in the blood, is linked to B7, B14 and HLA-A3. In about 70 percent of all hemochromatosis patients, HLA-A3 is seen. But, like the case of the other human leukocyte antigen linked disorders, the cost of HLA-typing trends favorably for using other tests. If a person is suspected to have hemochromatosis, diagnosis of the condition can be made with the help of two tests known as:

  • Serum ferritin

  • Transferrin saturation

Tags:

Category: Articles