HLA histocompatibility antigens are the gene regions that regulate the genetic identity on the surface of our cells. Based on this identity, the functioning of the immune system is regulated.

HLA gene regions are mainly tested for the compatibility or non-compatibility of transplants.

In daily life, however, they are examined for the investigation of pathological conditions of the immune system.

The most frequently analyzed areas and the corresponding associated diseases are:

1. HLA B-27 : Reactive arthritis, ankylosing spondylopathy
2. HLA DR2 : Systemic lupus erythematosus
3. HLA DR3: Autoimmune hepatitis, diabetes type I, Sjogren's syndrome
4. HLA DR4: Rheumatoid arthritis, diabetes type I
5. HLA DQ2 – DQ8 : Predisposition to Celiac Disease