SUSCEPTIBILITY OF PERIPHERAL-BLOOD MONONUCLEAR-CELLS TO APOPTOSIS IS CORRELATED TO PLASMA HIV LOAD

Objectives: To quantify spontaneous and activation-induced apoptosis i n peripheral blood mononuclear cells (PBMC) of HIV-infected patients a nd to look for correlations between PBMC apoptosis levels, stages of H IV disease, CD4 count, and plasma viral load. Study Populations: 75 co nsecutive inpatients and outpatients infected with HIV (mean CD4 count , 202 +/- 182 x 10(6)/L; mean plasma viral load, 4 +/- 1.29 log(10) RN A copies/ml) and a control group composed of 18 healthy, HIV-negative adults. Methods: Spontaneous apoptosis was detected at the single-cell level by direct incorporation of fluorescein-deoxyuridine triphosphat e (dUTP) in PBMC DNA strand breaks. Activation-induced apoptosis was d etermined after in vitro stimulation with anti-CD3 antibodies and inte rleukin-2 (IL-2). Results: Spontaneous apoptosis was low in patients a nd controls, whereas activation-induced apoptosis was significantly hi gher in HIV-infected patients (5.22 +/- 4.32% versus 2.46 +/- 1.77%, r espectively; p = .009). The degree of activation-induced apoptosis was positively correlated with the plasma viral load (r = 0.29; p = .029) and negatively correlated with the CD4 count (r = -0.37,p = .0009). A lthough activation-induced apoptosis was significantly higher in patie nts fulfilling AIDS criteria, it did not differ significantly between patients with an acute AIDS-defining event and those with stable disea se. Conclusion: Susceptibility of PBMC to apoptosis in HIV-l-infected patients is correlated to the plasma viral load and the stage of the d isease.