CONSTITUTIVE PRODUCTION OF PAI-II AND INCREASED SURFACE EXPRESSION OF GM(1) GANGLIOSIDE BY PERIPHERAL-BLOOD MONOCYTES FROM PATIENTS WITH AIDS - EVIDENCE OF MONOCYTE ACTIVATION INVIVO

To characterize the activation state of monocytes during human immunodeficiency virus (HIV) infection, peripheral blood monocytes (PBMs) from patients with acquired immunodeficiency syndrome (n = 10) and from healthy controls (n = 10) were cultured for 4 days. Monocyte culture supernatant (MCS) was collected daily, and levels of urokinase (UK) inhibitor PAI-II, a product of activated monocytes, released into MCS were determined (fibrin plate assay). To examine the activation state of PBMs independently, expression of GM1 ganglioside on PBMs from patients with AIDS (n = 9), patients with AIDS-related complex (ARC) (n = 8), HIV+ asymptomatic patients (n = 6), and HIV- healthy controls (n = 11) was determined (flow cytometry; living cells in suspension). Data are expressed as percent inhibition of UK, or as percent total cells. Patients' MCS collected on days 1-4 of culture contained similar levels of PAI-II because it inhibited UK in similar fashion (70-90%). In contrast, MCS from healthy controls, collected after 2 days, had decreased ability to inhibit UK (15-50%) and thus contained lower levels of PAI-II. Monocyte activation, measured by increased expression of GM1 ganglioside on PBM surfaces, directly correlated with the progression of HIV infection into the development of AIDS, since the order of magnitude of GM1 ganglioside expression on PBMs was AIDS > ARC > HIV+ asymptomatic = healthy controls. Our data indicate that PBMs from patients with AIDS are constitutively activated and suggest that activation directly correlates with disease progression.