" HIV infects and destroys CD4 T cells. Over time CD4 cell count goes down from 1000 cell/uL to below 50 cell/uL. Without treatment HIV can lead to AIDS. The CDC defines AIDS as the development of an AIDS-defining condition or a CD4 cell count less than 200 cells/μL in HIV-infected patients. AIDS defining illness or conditions occurring with variable CD4+ cell count include tuberculosis, karposi sarcoma and cervical cancer. Less than 200cells/ uL include infections such as pneumocystis jiroveci, progressive multifocal leukoencephalopathy. Less than 100 cell/uL aids defining illnesses that manifest include crytococcus meningitis, cryptosporidiosis and cerebral toxoplasmosis. When CD4+ cell counts become less than 50, CMV infections, primary CNS lymphoma and mycobacterium avium complex infections can occur"