HLA (human leukocyte antigen) is a genetic marker or “flag” that exists on the surface of each cell in our bodies. Its function is to help the immune system distinguish between “self” cells and “invader” cells. Individuals who have either HLA DQ2 or HLA DQ8 markers are at risk for developing celiac disease and the presence or absence of this genetic material can be useful information in diagnosing this disease.