14 month old with elevated LDH and ESR, slightly low HCT, swollen lymph nodes in neck, armpits and groin,?

on January 1st 2010, we noticed what appeared to be a swollen lymph node on my 14 month old granddaughters neck just below her ear, it was red and painful, she was taken to the doctor and put on a round of antibiotics, it went down some but another node appeared behind her ear, again a round of antibiotics was given , also blood work was taken, 2 weeks later at the doctors office, we were told her blood work had some elevated levels in nonspecific areas, and to come back in two weeks to see how she is doing, during this time she ran fevers for a couple of days, was sick with a "cold" or something a couple of times..at the next visit she was found to have more lymph nodes swollen in her armpit and now her groin area, both sides. her mother told the doctor she wasn't eating well, and slept a lot as well. and the first lump we found below her ear was red again. At this point the doctor said she didn't think that the one below her ear was even a lymph node but it felt more like a cyst now. and the other lymph nodes are still swollen. more blood work was taken, also noted she had lost a few ounces in weight. the blood work came back with still elevated levels of LDH and ESR and slightly low HCT, the LDH levels were in the 400's the first time and 300's the last time, she said she was testing her for cancer with the last round of blood work, and also did swabs for every virus and a HIV test and TB test, all of which were negative. Now she still doesn't know what is wrong with the baby, and is sending her to a infectious disease doctor..does anyone have any idea or know of any better tests we should be doing, this has been going on for over 2 months, would like to catch whatever it is as early as possible.