DECREASED FREQUENCY OF FUNCTIONAL NATURAL INTERFERON-PRODUCING CELLS IN PERIPHERAL-BLOOD OF PATIENTS WITH THE ACQUIRED-IMMUNE-DEFICIENCY-SYNDROME

Deficient in vitro production of interferon-alpha (IFN-alpha) in respo nse to herpes simplex virus (HSV) occurs in patients infected with the human immunodeficiency virus (HIV), with the most deficient responses associated with opportunistic infections (OI). The peripheral blood m ononuclear cells (PBMC) which produce IFN-alpha in response to HSV are light density, HLA-DR(+) cells lacking any unique surface markers and have been termed ''natural interferon-producing cells'' (NIPC). In th is study, IFN-alpha responses were measured and the ELISpot assay was utilized to determine the frequency of NIPC in response to HSV. As exp ected, HIV-infected patients had depressed IFN-alpha production. In th e ELISpot assay, healthy controls had a mean frequency of 1:703 NIPC a mong PBMC; each NIPC made approximately 2 international units (IU) of IFN-alpha. HIV-infected patients on average had fourfold less NIPC tha n controls and produced 1 IU IFN-alpha/NIPC; the plaque size for patie nt samples was often smaller than that for controls. NIPC frequency an d IFN-alpha production were lowest in patients with a history of OI. I n conclusion, deficient IFN-alpha production by AIDS patients results from reductions in both the frequency and the activity of NIPC, probab ly reflecting a gradual turning off of IFN-alpha production. (C) 1994 Academic Press, Inc.