A SIMPLE AND ROBUST METHOD FOR THE COMPLETE DISSOCIATION OF HIV-1 P24AND OTHER ANTIGENS FROM IMMUNE-COMPLEXES IN SERUM AND PLASMA SAMPLES

Accuracy of antigen determination in human plasma samples is often adv ersely affected by immune complex formation between antigens (e.g,, HI V-1 p24 protein) and specific antibodies. In this study we describe an optimized method for complete immune complex dissociation (ICD) in pl asma. This method is based on heat denaturation of antibodies and util izes a defined solution of sodium dodecyl sulfate (SDS) and diethylene triaminepentaacetic acid (DTPA) as diluent. The efficiency of this pro cedure for ICD was compared with those of published methods, employing heat denaturation alone and acidification. Plasma samples from patien ts participating in anti-retroviral treatments and samples reconstitut ed in vitro were treated and analyzed in parallel. HIV-1 p24 antigen w as determined by quantitative enzyme-linked immunosorbent assay (ELISA ). In 312 samples from 97 patients, antigenemia was found in 44.9% whe n measured directly and in 87.2% after this treatment. In a subset of 56 samples, 21.4% tested positive prior to treatment, while after eith er novel treatment, heat denaturation or acidification, these samples tested positive in 80.4%, 62.5% and 60.7%, respectively. In 94% of cas es viral RNA was detected. This improved procedure for ICD provides a reliable and convenient method for complete and accurate p24 antigen d etection in human plasma and is applicable to commercially available t est kits. (C) 1998 Elsevier Science B.V. All rights reserved.