HIV positive patients are currently the focus of multiple collaborative research studies, both at UCSF and other institutions. The aims of these research projects include improving the understanding of etiology, immunology, epidemiology and treatment of HIV. There are numerous requests from basic scientists at UCSF for collaborative studies on specimens, especially for blood, saliva and urine samples. Specimens may be used to test such things as virus characteristics, genotyping and/or phenotyping resistance, plasma drug concentrations, immune function or evidence of complications of HIV disease. The samples may also be tested for genetic factors that may be related to the course of HIV disease