HLA Typing for Celiac Disease

The HLA Typing for Celiac Disease test contains 1 test with 6 biomarkers.

Brief Description: The HLA (Human Leukocyte Antigen) Typing for Celiac Disease test is a genetic test that identifies specific HLA gene variants associated with an increased risk of developing celiac disease. Celiac disease is an autoimmune disorder triggered by the ingestion of gluten, a protein found in wheat, barley, and rye. This test aids in assessing the genetic predisposition to celiac disease.

Also Known As: Tissue Typing Test, HLA Typing Test, Histocompatibility Test, HLA Crossmatching Test, HLA Screening Test

Collection Method: Blood Draw

Specimen Type: Whole Blood

Test Preparation: No preparation required

When is an HLA Typing test ordered?

Recipients of transplants: When an individual's need for an organ or bone marrow transplant is first determined, HLA gene, antigen, and antibody testing is frequently carried out. Results for HLA genes and antigens won't alter over time.

Donors for transplants: When family members volunteer, their HLA gene or antigen typing is done to see whether they are a match for a relative who need a kidney, liver, bone marrow, or other type of transplant. It is also possible to examine living, unrelated individuals as potential organ donors, which is commonly the case with kidney transplants. On unrelated people who sign up for the donation register to become bone marrow donors, HLA typing is also carried out.

HLA testing is carried out on organs from deceased donors in order to match them as fast as feasible to a potential receiver or recipients. A few hours to no more than a day or two are necessary to assure the optimum viability of the organs or tissues.

After a possible donor has been located using HLA typing, crossmatch testing is conducted. Usually, this test is run right before an organ transplant to make sure there are no mismatches. Crossmatch compatibility tests are typically conducted twice in the event of living donor transplantation—once when the donor is first identified and once right before the donation itself.

What does an HLA Typing test check for?

The MHC, also known as the major histocompatibility complex, contains human leukocyte antigens. They refer to the genes that code for specific specialized proteins that are found on the surface of all nucleated cells in the body. Each person's white blood cells and other cells with a nucleus have a hereditary combination of HLA antigens on their surface. A person's primary HLA genes and the accompanying antigens that are found on their cell surfaces can be determined by HLA testing.

The MHC system and HLA antigens are crucial components in the control of the immune system. They aid the body's immune system in differentiating between "self" and "foreign" or "non-self" cells. An immunological response, which includes the formation of antibodies, can be triggered by any cells that are regarded as "non-self."

When transplanting tissue or an organ, this is crucial in medicine. For a bone marrow transplant to be effective and for the tissue to not be attacked or rejected by the recipient's immune system, the HLA genes of the donor and recipient must match exactly or as closely as feasible. In order to prevent graft-versus-host disease, which occurs when the immune cells in donated bone marrow attack the recipient's cells, bone marrow donors and recipients must also closely match.

It is preferable for the donor and recipient's antigens to match in solid organ transplants, such as kidney or lung transplants; however, typing incompatibilities are less important as long as the recipient has not created antibodies that are specific to the donor's antigens. To lessen organ rejection, a variety of medications may be given to assist suppress the recipient's immune system.

The likelihood of rejection in the immediate post-transplant period is lower when the donor organ and the intended recipient are compatible. Organ and tissue transplant donors are identified, and recipients are matched with donors who have the same or an appropriate amount of matching HLA genes and antigens, using HLA testing and ABO blood typing.

Sometimes it can be challenging to find a donor who is compatible with the intended recipient. The fact that each specific HLA gene can take on a wide variety of forms or variants is one factor. It is known as polymorphic in this case. The extensive "gene family" of the HLA system is made up of more than 200 genes in total. Finding a suitable donor might be difficult because there are so many distinct HLA gene combinations that could occur.

However, clusters of HLA genes, such as those found on chromosome 6, are inherited collectively as haplotypes; as a result, a kid receives one haplotype from each parent. Because of this, family members are more likely than unrelated potential donors to share the same group of HLA genes. The finest transplant matches frequently come from a recipient's parents, kids, or siblings.

Lab tests often ordered with an HLA Typing test:

When HLA Typing for Celiac Disease is ordered, it's often part of a broader evaluation of gastrointestinal symptoms and malabsorption. Here are some tests commonly ordered alongside it:

1. Tissue Transglutaminase Antibodies (tTG-IgA and tTG-IgG):

   • Purpose: To detect antibodies typically elevated in celiac disease.
   • Why Is It Ordered: These are primary tests for diagnosing celiac disease. tTG-IgA is the most sensitive test, but tTG-IgG is used in individuals with IgA deficiency.

2. Total Serum IgA:

   • Purpose: To measure the level of Immunoglobulin A (IgA) in the blood.
   • Why Is It Ordered: To check for selective IgA deficiency, which can lead to false-negative results in IgA-based celiac disease tests like tTG-IgA.

3. Endomysial Antibody (EMA) IgA:

   • Purpose: To detect antibodies that target the endomysium, a component of the intestine.
   • Why Is It Ordered: EMA IgA is highly specific for celiac disease and is often used to confirm positive tTG tests.

4. Deamidated Gliadin Peptide (DGP) Antibodies (IgG and IgA):

   • Purpose: To detect antibodies against deamidated gliadin peptides.
   • Why Is It Ordered: These tests are useful particularly in children under 2 years of age and in cases where tTG or EMA tests are inconclusive.

5. Complete Blood Count (CBC):

   • Purpose: To evaluate overall blood health.
   • Why Is It Ordered: To assess for signs of anemia or other blood cell changes that can be associated with celiac disease due to malabsorption.

6. Iron Studies:

   • Purpose: To evaluate iron status.
   • Why Is It Ordered: To assess for iron deficiency anemia, which is common in celiac disease due to malabsorption.

7. Vitamin and Mineral Levels (such as Vitamin D, B12, Folate):

   • Purpose: To measure levels of key vitamins and minerals.
   • Why Is It Ordered: To evaluate for deficiencies common in celiac disease due to malabsorption.

These tests, when ordered alongside HLA Typing for Celiac Disease, provide a comprehensive assessment of potential celiac disease. They are crucial for diagnosing the condition, understanding its impact on the patient's health, and guiding dietary and treatment strategies. The specific combination of tests will depend on the individual’s symptoms, family history, and risk factors.

Conditions where an HLA Typing test is recommended:

The HLA Typing for Celiac Disease test is specifically ordered for assessing the genetic risk of developing celiac disease, an autoimmune disorder triggered by the ingestion of gluten.

How does my health care provider use an HLA Typing test?

Human leukocyte antigen tests are primarily used to pair suitable organ and tissue transplant candidates with compatible donors. It determines which major HLA genes an individual inherited and which related antigens are present on the cell surface. These antigens aid the body's immune system in differentiating between "self" and "foreign" or "non-self" cells. An immune response, including the formation of antibodies, can be brought on by any cells that are regarded as "non-self."

When transplanting tissue or an organ, HLA testing is crucial in medicine. For effective bone marrow transplants, the recipient's immune system must not attack or reject the transplanted tissue, hence the HLA genes and antigens of the donor and recipient must match exactly or as closely as feasible.

Different types of transplants demand various degrees of compatibility between the intended recipient and the donor. This could affect the HLA tests that are run and the HLA genes that are examined.

In order to evaluate compatibility, HLA testing normally consists of three parts:

Identifying HLA alleles is required for HLA typing of donors and recipients. It could involve molecular typing or serological HLA testing.

HLA testing is done on family members who voluntarily give bone marrow or organs to determine if they are a match for the relative in need of the donation.

People can register with a national registry, such as the United States National Marrow Donor Program, if they desire to make themselves available to give bone marrow to anyone who needs it. The findings of the HLA testing are recorded and can be compared to those of those looking for a match.

After a potential donor has been found, the lymphocyte crossmatching procedure is carried out. It assists in determining whether the prospective recipient has antibodies against antigens found on the lymphocytes of the donor. White blood cells from the donor are combined with serum from the intended recipient. Any reaction would likely be a sign that the two are incompatible. The recipient's HLA antibodies and the donor's HLA typing should always be considered when interpreting the crossmatch result.

Testing for the HLA gene may occasionally be used to help identify an autoimmune disease. One of the systems responsible for the body's detection of "self" and "non-self" antigens and the immune response to foreign substances is the HLA system. Antibodies can be produced when the body unnecessarily mounts an immunological defense against its own cells. It has been discovered that several disease states are linked to specific HLA antigens, such as ankylosing spondylitis, which is linked to HLA-B27. Given that some pharmaceuticals and particular HLA types have been linked to adverse effects, HLA typing may be crucial in averting reactions to specific treatments.

What do my HLA Typing test results mean?

During HLA typing, particular HLA genes or antigens are found to be compatible with organ and tissue transplants. Transplant recipients' genes and/or antigens are compared to those of potential donors. The results show the number of antigens that match and the number of mismatches. The likelihood that the transplant will be successful increases with the number of matches. A high likelihood that the organ or tissue won't be rejected by the recipient is indicated by "0 mismatches."

A high risk transplant is typically considered when a crossmatch result is positive. These patients run the risk of transplant rejection, which may or may not be managed with different immunosuppressant medications.

Most Common Questions About the HLA Typing for Celiac Disease test:

Clinical Utility and Interpretation

What is the primary purpose of the HLA Typing for Celiac Disease test?

The HLA Typing for Celiac Disease test identifies specific human leukocyte antigen (HLA) alleles that are associated with an increased risk of celiac disease. The presence of these alleles (especially HLA-DQ2 and HLA-DQ8) suggests a genetic predisposition to celiac disease but does not confirm the diagnosis.

How does the HLA Typing for Celiac Disease test contribute to the overall diagnosis of celiac disease?

The test helps in excluding celiac disease as a diagnosis. If neither HLA-DQ2 nor HLA-DQ8 are detected, the likelihood of celiac disease is low. However, having these alleles does not confirm celiac disease; it only suggests a genetic susceptibility. Other diagnostic tests and clinical evaluation are necessary for a definitive diagnosis.

Clinical Applications and Diagnoses

Can the HLA Typing for Celiac Disease test alone diagnose celiac disease?

No, while the presence of HLA-DQ2 or HLA-DQ8 increases the risk of celiac disease, not everyone with these alleles will develop the condition. The test is useful in a diagnostic context, especially when results from other celiac disease tests are ambiguous.

When might a physician order the HLA Typing for Celiac Disease test?

Physicians might order the test when symptoms suggestive of celiac disease are present, but other tests (like the tTG-IgA test) are inconclusive. It can also be used to determine the genetic risk in first-degree relatives of individuals diagnosed with celiac disease.

Comparative Insights

How does the HLA Typing for Celiac Disease test compare to other diagnostic tests for celiac disease?

Other diagnostic tests for celiac disease, like the tTG-IgA test or endoscopic biopsy, directly measure the immune response or inflammation in the small intestine, respectively. The HLA typing test, on the other hand, assesses genetic predisposition. It's complementary to these tests rather than a replacement.

Understanding Limitations and Challenges

What's the significance of a negative result in the HLA Typing for Celiac Disease test?

A negative result, meaning the absence of the HLA-DQ2 and HLA-DQ8 alleles, significantly reduces the likelihood of celiac disease. It's estimated that about 95-99% of individuals with celiac disease have one of these alleles. Thus, its absence makes celiac disease highly unlikely.

Is it possible to develop celiac disease even if the HLA Typing for Celiac Disease test is negative?

While extremely rare, there are cases of celiac disease in individuals who do not possess the HLA-DQ2 or HLA-DQ8 alleles. Always consult with a healthcare provider for a comprehensive diagnosis.

Additional Questions and Insights

Why might a person with a positive HLA Typing for Celiac Disease test not exhibit any symptoms of the disease?

While the presence of HLA-DQ2 or HLA-DQ8 indicates a genetic predisposition to celiac disease, it does not guarantee the onset of the disease. Many individuals with these alleles never develop celiac disease. Environmental factors, other genetic factors, and the presence of certain triggering events may play a role in the actual development of the condition.

Can the HLA Typing for Celiac Disease test be used to assess the risk of other autoimmune conditions?

Yes, certain HLA types are also associated with other autoimmune disorders, although the HLA Typing for Celiac Disease test specifically targets those alleles linked to celiac disease. If there's a suspicion of another autoimmune condition, specific tests tailored to that condition would be more appropriate.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.