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HLA-DQA1, Molecular Typing

Human Leukocyte Antigens (HLA), or otherwise Histocompatibility Antigens, are proteins that are present on the surface of each cell and allow the immune system to recognize the "self" from the "foreign". The antigens are divided into HLA-A, HLA-B, HLA-C (Class I Histocompatibility Antigens) and HLA-DP, HLA-DQ, and HLA-DR (Class II Histocompatibility Antigens). HLA antigens are closely related gene products located on chromosome 6.

The HLA-DQA1 gene provides instructions for making a protein that plays a critical role in the immune system. The HLA-DQA1 gene is part of a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders such as viruses and bacteria.

The HLA complex is the human version of the major histocompatibility complex (MHC), a gene family that occurs in many species. The HLA-DQA1 gene belongs to a group of MHC genes called MHC class II. MHC class II genes provide instructions for making proteins that are present on the surface of certain immune system cells. These proteins attach to protein fragments (peptides) outside the cell. MHC class II proteins display these peptides to the immune system. If the immune system recognizes the peptides as foreign (such as viral or bacterial peptides), it triggers a response to attack the invading viruses or bacteria.

The protein produced from the HLA-DQA1 gene attaches (binds) to the protein produced from another MHC class II gene, HLA-DQB1. Together, they form a functional protein complex called an antigen-binding DQαβ heterodimer. This complex displays foreign peptides to the immune system to trigger the body's immune response.

Each MHC class II gene has many possible variations, allowing the immune system to react to a wide range of foreign invaders. Researchers have identified hundreds of different versions (alleles) of the HLA-DQA1 gene, each of which is given a particular number (such as HLA-DQA1*05:01).

Class II molecules are expressed in antigen-presenting cells (B lymphocytes, dendritic cells, macrophages). The alpha chain is approximately 33-35 kDa. Within the DQ molecule, both the alpha chain and the beta chain contain the polymorphisms specifying the peptide binding specificities, resulting in up to four different molecules. 

Health Conditions Associated with different HLA-DQA1

Celiac disease, alopecia areata, autoimmune Addison disease, idiopathic inflammatory myopathy, juvenile idiopathic arthritis, narcolepsy, rosacea, type 1 diabetes, autoimmune diseases, other diseases

This assay is designed to provide low-to-medium resolution for HLA typing.


Important Note

Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".

Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.

At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.



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