Sick dog...?

My 5 month old male Shetland sheepdog was given a blood test as a routine precursor to being neutered. The test results revealed a white blood cell count of over 60,000, which is, I am told, more than ten times the normal reading. Numerous tests ensued: more blood tests, ultra sounds of his liver and heart, a liver biopsy and an attempt at a bone marrow aspirant (which failed, as the vet was only able to extract blood). It was determined that his liver and his gall bladder were both greatly enlarged. He was also tested for various tick-borne diseases. All tests came back negative. He was put on a course of antibiotics (Clavamox 375 mg per day). Subsequent blood tests revealed no change in his white blood cell count. I should add that Bailey’s health otherwise appears excellent. He is full of energy, is playful, and alert. There appears to be no outward sign of any illness. The doctors are stumped. I ume that the next step will be to send him to some kind of specialist. Has ANYONE had any experience with these types of symptoms? If so, what was the diagnosis and/or resolution?