Immunoregulation, immune defects, and clinical strategies in HIV infection

In summary, patients with HIV infection have a variety of immunologic defects. The hallmark defect is a decrease in the number and function of helper-inducer or CD4 T lymphocytes. A decrease in CD4 count to less than 200 is associated with the development of opportunistic infections. The earliest functional defect is in soluble antigen recognition. Although there is an increase in the number of suppressor cytotoxic or CD8 T lymphocytes, there is a decrease in their function, presumably due to a lack of inductive signals from the CD4 T cells. Decreases in natural killer cell function occur, as does polyclonal B cell activation, which makes serologic diagnosis of opportunistic infections somewhat unreliable. Finally, there are also variable decreases in the function of the reticuloendothelial system.