Deficient, HLA-Restricted, Cytomegalovirus-Specific Cytotoxic T Cells and Natural Killer Cells in Patients with the Acquired Immunodeficiency Syndrome

The specific defects in cellular immunity that are associated with the acquired immunodeficiency syndrome (AIDS) are of interest with respect to defining what direct or indirect effects the causative agent may have that result in a patient's susceptibility to opportunistic infections. An opportunistic agent of particular importance in AIDS with respect to frequency and severity of infections is cytomegalovirus (CMV) [1]. In other populations of patients with depressed cellular immunity in whom CMV infections are also important, such as transplant recipients, studies of cellular immunity have helped to establish which effector cells are important for determining resistance to CMV infections [2, 3]. Deficiencies in cytotoxic T cell responses and natural killer cell (NKC) activity correlate with serious or fatal effects of CMV infections. Otherwise healthy individuals with CMV infections usually develop HLA-restricted, CMV-specific cytotoxic T cell responses and increases in NKC cytotoxicity [4]. Deficiencies in these effector cell types might explain why patients with AIDS are susceptible to opportunistic infections in general, and definition of the mechanisms for such deficiencies might lead to approaches to therapy. We studied the frequency and severity of deficiencies of these cytotoxic cells in patients with AIDS. We previously reported results of similar tests on six patients selected for their severely depressed NKC activity [5]. The present study is a more comprehensive evaluation.