Good Luck with this one Belinda, sounds like there is no quick cure. Do you suffer from stress / anxiety. My GP puts my low immunity down to this (although quite how you get a test for low immunity in the UK I do not know). Do you live in the US ? I recently went to my GP as I had 4 illnesses within 4 months. My GP will not give me the white blood cell reactivity test (T suppressor cell), apparently because it's a fiddly test and may show a reliable result but may not (so it sounds like it's down to NHS costs). Instead my GP gave me all the standard tests - chloresterol, thyroid etc which I knew would come back negative.