For a new angle on this, I'd look at what Hulda Clark 's research has revealed about HIV. It's call parasites and chemicals in the Thymus gland, which is located in the upper anterior chest and the Thymus gland is THE immunity organ...among others. Also, benzenes accumulate there and the flukes follow and thrive. Here's a free PDF file for Clarks book...study it...this material is priceless.