One of the major problems in defining the immunopathogenic changes in HIV infections has been the inability to correlate the extent of loss of immunologic function with the number of HIV-infected CD4+ cells in the peripheral blood. Few studies exist that measure viral burden in lymph nodes of HIV-infected individuals. Researchers hope to find out whether the amount of HIV virus or markers for the virus in the body's lymph tissue is a better measure of disease progression than the amount of virus or markers for the virus in the blood.