HIV-1 antigen-specific and -nonspecific B cell responses are sensitive to combination antiretroviral therapy. in production, the OraQuick ADVANCE Rapid HIV-1/2 antibody test (OQ) (8), the Reveal G2 Rapid HIV-1 antibody test (5), and the Uni-Gold Recombigen HIV immunoassay (11). Multispot, a flowthrough device, employs the immunoconcentration method (12) to detect antibodies that bind to immobilized microparticles coated with antigen representing portions of transmembrane proteins of HIV-1, HIV-2, and a control immunoglobulin G (IgG), as shown in Table ?Table11. TABLE 1. Identification CP-809101 of microparticle types used in the Multispot device= 248. Dx, diagnosis. bValue is a percentage. cValue is the mean SD. The range is given in parentheses. dValue is the number of patients. The value in parentheses is a percentage. eViral load is expressed as a geometric mean. The range is given in parentheses. TABLE 3. Comparative reactivities between the current Multispot study and OQ HIV-1 false-negative specimens = 248) (= 4) was 0.0001 for all comparisons except for spot 2 and gp160, where the value was 1.000 (Mann-Whitney U). cHIV-1 positivity was determined by a comparison of EIA and WB results. The additional four archived specimens acquired from subjects that tested false negative by OQ were all HIV-1 reactive using Multispot and EIA/WB (Table ?(Table3).3). Compared to the 248 TACC NHS specimens, these sera demonstrated weaker Multispot semiquantitative reactivity at spot 3 (3.64 versus 2.25; 0.001) and spot 4 (3.94 versus 2.00; 0.001), in spite of demonstrating stronger reactivity at spot 1 (3.13 versus 3.75; 0.001). WB semiquantitative reactivity was also lower in the samples that tested false negative by OQ at p24, gp41, and gp120 ( 0.001 for CP-809101 all comparisons) but not gp160. This study supports the use of Multispot in settings where test subjects might be HAART exposed with attendant low or undetectable anti-gp41 antibody titers. Low titers were suggested by weak semiquantitative reactions in some individuals, but reactivity remained above the level of Multispot detection. Because a single specialized immunology technologist performed the Multispot testing, the performance characteristics of Multispot in this evaluation may not be generalizable to settings where testing is performed by laboratory generalists. Multispot sensitivity (100%; 95% CI, 98.80 to 100.00) was superior to OQ sensitivity (7) in this population (96%; 95% CI, 90.17 to 98.91; = 0.00672). The explanation for this difference may involve the flowthrough immunoconcentration design of Multispot, which affords the detection of lower antibody titers than the lateral-flow approach employed by OQ. Differences in antigen structure and preparation may also explain these findings, but the exact composition of antigens is not available for either device (1, 8). It is unlikely that our observations are due to subject selection bias, as similar subjects were drawn from the same population using the same approach in both studies and because Multispot correctly identified samples from individuals who had a false-negative result by OQ. While we did not perform live, side-by-side comparisons between OQ and Multispot for this study, having done so would have been unlikely to yield different results, since the two studies drew from the same patient population, used serum samples from the same repository, included a substantial number of the same individuals, and identified similar decrements in WB gp41 bands in the OQ false-negative specimens. Acknowledgments CP-809101 Support for this work came from the U.S. Military HIV Research Program (cooperative agreement W81XWH-04-02-005). USMHRP is a DOD triservice program executed through the U.S. Army Medical Research and Materiel Command, the Walter Reed Army Institute of Research, and the Henry M. Jackson Foundation in direct partnership with the U.S. Department of Health and Human Services, the National Institutes of Health, and the National Institute for Allergy and Infectious Diseases. The views and opinions expressed herein do not MGC129647 necessarily reflect those CP-809101 of the U.S..
