What does a highly elevated antinuclear antibody result mean exactly? Does it mean sle?

Not necessarily. In addition to sle a positive ana(antinuclear antibody) can be seen in a number of medical conditions, secondary to certain medications, and in otherwise healthy individuals. Therefore a positive ANA does not necessarily indicate the presence of sle.
ANA. It simply means that an underlying autoimmune process is occurring inside the body. Oftentimes the test will be repeated to ensure accuracy. The next step is to identify which autoimmune or connective tissue disease is present, typically with more specific antibody testing.