A cluster of patients with recombinant B/F HIV‐1 infection: Epidemiological, clinical, and virological aspects

Abstract

Migratory processes have caused changes in human immunodeficiency virus (HIV) epidemiology and non‐B subtypes are now playing an increasing role. In a cohort of 553 HIV‐infected outpatients tested to identify non‐B isolates, the largest group consisted of 13 subjects with a recombinant B/F form (prevalence 2.4%). Sequencing and phylogenetic analyses described a B/F recombinant clade with anomalous breakpoints that did not allow it to be classified as CRF12_BF. Viral load was not quantified efficiently because of a mismatch in the primers and probes used by commercial assays. An assessment of the clinical management, and epidemiological, immunological, and virological characteristics of these patients, who were receiving non‐nucleoside reverse transcriptase inhibitor (NNRTI)‐ or protease inhibitor (PI)‐based regimens, showed that the immunological and virological mismatch delayed the start of treatment by a mean of 6.8 months. Therapy was started in nine patients. Both NNRTI‐ and PI‐based regimens led to full virological suppression after a mean 36 weeks of treatment; the PI‐based regimens proved to be more effective in terms of immunological recovery (1,341 vs. 544 CD4+ cells/mm3). The spread of non‐B subtypes is increasing throughout the world but their response to treatment is still unclear. PIs and NNRTIs are effective but further tests are needed to allow the more efficient recognition of these viral strains and establish how they should be treated. J. Med. Virol. 83:1493–1498, 2011. © 2011 Wiley‐Liss, Inc.

Minimal sequence variability of the region of HIV-1 integrase targeted by the Abbott RealTime HIV-1 viral load assay in clinical specimens with reduced susceptibility to raltegravir

“…Such evolution can be a challenge for the design of molecular diagnostic assays that rely on reactivity of synthetic primers and probes within the target sequence. Thus, numerous publications have described underestimation of plasma viral load in the setting of non-B subtypes, or in specimens that have divergent sequence in critical positions (Bolivar et al, 2009;Damond et al, 2007;Delaugerre et al, 2009;Foglieni et al, 2011;Holguin et al, 2008;Korn et al, 2009;Pyne et al, 2010;Rossotti et al, 2011;von Truchsess et al, 2006;Yotsumoto et al, 2011). Notwithstanding these observations, the Abbott RealTime HIV assay has performed well in studies with divergent sequences in critical positions and certain non-B subtypes (Swanson et al, 2006a(Swanson et al, ,b, 2007.…”