title: p24 Antigen detection assay modified with a booster step for diagnosis and monitoring of human immunodeficiency virus type 1 infection.
abstract: We modified a p24 antigen enzyme-linked immunosorbent assay as a method for diagnosis and monitoring of human immunodeficiency virus type 1 (HIV-1) subtype E infection. This modified assay is based on the use of preheated immune complex dissociation combined with a booster step using a regular Vironostika HIV-1 p24 antigen assay (bioMerieux) to decrease the lower limit of p24 antigen detection from 10 pg/ml (lower limit achievable when using a regular p24 antigen assay) to 0.5 pg/ml (100 virions/ml) by the new method. The correlation between the values obtained by the HIV-1 RNA (Amplicor HIV-1 Monitor) assay and the p24 antigen assay modified with a booster step antigen assay in 160 frozen plasma samples with known viral load and 80 blind fresh plasma samples by Spearman rank were 0.671 (R(2) = 0.450; P < 0.01) and 0.782 (R(2) = 0.612; P < 0.01). During antiretroviral treatment, the change of p24 antigen level at >/=0.5 log correlated well with the level of HIV-1 in plasma. In order to improve the early diagnosis of HIV-1 infection in 121 infants born to HIV-1-infected mothers, a heat-denatured plasma p24 antigen assay modified with a booster step was compared with DNA-PCR and HIV RNA (nucleic acid sequence-based amplification) assays. The sensitivity of the antigen test modified with a booster step was similar to that of the HIV-1 RNA (NASBA QL) assay and better than that of the DNA-PCR assay (100 versus 61.90%) for subjects 1 to 2 months old. The overall results from this study might renew interest in p24 antigen detection as an easily affordable alternative method for diagnosis of HIV-1 infection and monitoring of disease progression in developing countries.
authors.affiliation: Departments of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. sirst@mahidol.ac.th
authors.forename: Ruengpung
authors.initials: R
authors.lastname: Sutthent
authors.forename: Narintorn
authors.initials: N
authors.lastname: Gaudart
authors.forename: Kulkanya
authors.initials: K
authors.lastname: Chokpaibulkit
authors.forename: Nattaya
authors.initials: N
authors.lastname: Tanliang
authors.forename: Chinda
authors.initials: C
authors.lastname: Kanoksinsombath
authors.forename: Pongsakdi
authors.initials: P
authors.lastname: Chaisilwatana
mesh_terms: D000956:Antigens, Viral / Q000032:analysis*; D019937:Diagnostic Techniques and Procedures; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D016655:HIV Core Protein p24 / Q000032:analysis*; D015658:HIV Infections / Q000175:diagnosis*; D015497:HIV-1 / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000032:analysis; D019562:Viral Load
chemical_list: D000956:Antigens, Viral; D016655:HIV Core Protein p24; D012367:RNA, Viral