FREE, DECOMPLEXED AND PRECIPITATED P24 HI V-1 ANTIGENEMIA IN BLACK-PEOPLE

P24/HIV-1 antigen in the sera from 41 HIV-l-infected Black individuals , living in the Central African Republic (n=17) and in France (n = 24) , and in 21 HIV-l-infected Caucasians patients, matched on the stages of the disease, has been detected and quantified by ELISA, without and with acid pretreatment of the sera by HCl or by glycine, and after ul tracentrifugation of serum. Free p24 antigenemia was detected less fre quently in Black patients (9.7 %), than in Caucasian controls (33 %) ( p <0.05). Decomplexed p24 antigenemia was detected in 34 % of patients after dissociation of circulating immune complexes (CIC) by HCl (p <0 .01) and in 44 % of patients after dissociation of CIC by glycine (p < 0.001). However, the mean concentration of decomplexed p24 antigenemia of positive sera was higher after pretreatment by HCl (88 pg/ml) than by glycine (52 pg/ml), suggesting that a strong acid is more convenie nt than a weak one to disrupt the CIC in Black individuals. After ultr acentrifugation of the serum, the detection of p24 antigen was not sig nificantly increased. Acid dissociation of CIC is a usefull method to increase the sensitivity of detection of circulating p24 antigen in HI V-l-infected Black individuals.