INCREASED SOLUBLE CD14 SERUM LEVELS AND ALTERED CD14 EXPRESSION OF PERIPHERAL-BLOOD MONOCYTES IN HIV-INFECTED PATIENTS

Serum levels of soluble CD14 were elevated in HIV-infected asymptomatic patients or those with lymphadenopathy (CDC II/III) 2.9 +/- 0.8 mg/l compared with normal controls with 2.2 +/- 0.47 mg/l, P < 0. 001. A further rise was seen in patients with ARC (CDC IVA) 3.8 +/- 1.1 mg/l, P < 0. 01 and patients with AIDS (CDC IVB-D) 5. 7 +/- 2. 5 mg/l, P < 0 .01. Although absolute numbers of CD14 + cells decrease in the AIDS group, the percentage of CD14(+) monocytes did not change. In contrast, levels of soluble T cell antigens sCD4 and sCD8, which are higher in HIV-infected patients compared with normal subjects, showed no increase with disease progression. Serum levels of sCD14 were correlated positively with beta(2)-microglobulin levels (r(s) = 0.63, P < 0.0001). Whereas the percentage of CD14(+) monocytes did not change, an increase in monocytic CD14 expression in HIV-infected patients was observed (P < 0.01). The percentage of a monocyte subset expressing both CD14 and CD16 increased from 6% in normal healthy persons to 13% in HIV-infected patients (P < 0.001), and did not vary between the HIV patient groups. Incubation of cultured peripheral blood monocytes with azidothymidine had no effect on either normal or LPS-induced or IL-4-inhibited sCD14 release in vitro. Therefore, an effect of AZT on sCD14 serum values in vivo is considered to be unlikely. Our data further provide evidence that monocytes/macrophages are engaged in HIV infection.