title: Quantitative detection of plasma human immunodeficiency virus type 2 subtype A RNA by the Nuclisens EasyQ Assay (version 1.1).
abstract: No commercial viral load assay has yet been approved for use for measurement of human immunodeficiency virus type 2 (HIV-2) RNA levels in plasma. We assessed the performance of the NucliSens EasyQ (version 1.1) assay (EasyQ; bioMérieux, Boxtel, The Netherlands) to quantify HIV-2 viremia. A viral stock was prepared from an HIV-2 (subtype A)-infected patient. Culture supernatant was subjected to viral particle counting by electron microscopy. Serial dilutions of the viral stock were made in HIV-negative plasma and were used to test EasyQ for its sensitivity, linearity, and reproducibility. RNA was quantified by the NucliSens EasyQ (version 1.1) assay. Plasma samples from 75 HIV-2-infected patients were further tested. EasyQ was able to quantify HIV-2 RNA in a reproducible manner. Overall, estimates of the number of HIV-2 RNA copies/ml obtained with EasyQ were lower than those obtained by electron microscopy; however, the differences were always less than 0.7 log (mean, 0.55 +/- 0.19 log(10)). The assay showed good linearity (r(2) = 0.964; P < 0.0001). The agreement between both measures was assessed by use of a Bland-Altman plot; the narrow limits (0.158 to 0.952), defined as the mean difference +/- 2 standard deviations, indicated good agreement. The reproducibility was also good, since the between-run coefficients of variation were 1.49, 3.60, and 12.25% for samples containing 6.30, 4.30, and 2.30 log(10) HIV-2 RNA copies/ml, respectively. HIV-2 RNA was detected in 34 of 75 (45%) plasma specimens (mean, 2.72 log RNA copies/ml; range, 1.74 to 4.11 log RNA copies/ml); the rest of the specimens were considered to have undetectable viremia. A negative correlation was found between the number of HIV-2 RNA copies/ml and CD4 counts. In summary, EasyQ was shown to be reliable for the measurement of plasma HIV-2 subtype A RNA levels and may be a feasible tool for routine clinical monitoring of HIV-2 subtype A-infected patients.
authors.affiliation: Department of Infectious Diseases, Hospital Carlos III, Sinesio Delgado, 10, Madrid 28029, Spain. brodes.hciii@salud.madrid.org
authors.forename: Berta
authors.initials: B
authors.lastname: Rodés
authors.forename: Julie
authors.initials: J
authors.lastname: Sheldon
authors.forename: Carlos
authors.initials: C
authors.lastname: Toro
authors.forename: Laureano
authors.initials: L
authors.lastname: Cuevas
authors.forename: Esperanza
authors.initials: E
authors.lastname: Pérez-Pastrana
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Herrera
authors.forename: Vincent
authors.initials: V
authors.lastname: Soriano
mesh_terms: D015658:HIV Infections / Q000175:diagnosis / Q000821:virology*; D015498:HIV-2 / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D012367:RNA, Viral / Q000032:analysis / Q000097:blood*; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019562:Viral Load
chemical_list: D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic