Testing positive for either HLA-DQ2 or HLA-DQ8 does not mean you have to change your eating habits unless you have symptoms of the disease (including damage to the villi that line the small intestines). The test will simply tell you that you have a propensity for the disease, nothing more.
With that being said, most celiac specialists will advise you and your family to be regularly monitored in the event one or more of you eventually become symptomatic. This is because the HLA mutations are passed from parent to child, with some children inheriting two copies of the mutation (one from each parent) while others only inheriting one. Those inheriting two are at greatest risk.
If you have symptoms and all other test results are negative, a positive HLA test may justify a trial period during which you stop gluten to see if your symptoms improve.