First things first. I do not treat a laboratory result, I treat a patient. Tell me what is wrong with Luke.
What clinical signs are you seeing that required a course of antibiotics and testing for FeLV and FIV?
Do you know the values of his CBC (white blood cells and red blood cells and platelet counts)?
Is he still eating/drinking?
Is there any vomiting/diarrhea?
Does he ever go outside? If so, what percentage of the time?