I am not what you would call a church goer. But I am not a fool. My wife was sick-in bed about 95% of the time for 14 months. During that period we saw 5 doctors and every test they could think if from scans, to "t" cells to oncologist to aids test. Including evaluation for depression- which were also negative. Yet she was always tired and always had a secondary infection from thrush to mono to sinus to flue. Finally after 70 test, doctors visits, total, I was told because of her failing immune system she would not make another year. Well the last visit to the immunoligist I was told I might want to try allergy proffing the house it might help with some of her secondary infections. Well I did that, no carpets, soft furniture, and all mattress in sealed plastic etc. My wife was normal in three days what we found out latter was that dust mites were the culprit!!! She has now been fine for two years. Immune syst normal!