title: Human immunodeficiency virus type 1 superinfection was not detected following 215 years of injection drug user exposure.
abstract: Evidence for human immunodeficiency virus type 1 (HIV-1) superinfection was sought among 37 HIV-1-positive street-recruited active injection drug users (IDUs) from the San Francisco Bay area. HIV-1 sequences from pairs of samples collected 1 to 12 years apart, spanning a total of 215 years of exposure, were generated at p17 gag, the V3-V5 region of env, and/or the first exon of tat and phylogenetically analyzed. No evidence of HIV-1 superinfection was detected in which a highly divergent HIV-1 variant emerged at a frequency >20% of the serum viral quasispecies. Based on the reported risk behavior of the IDUs and the HIV-1 incidence in uninfected subjects in the same cohort, a total of 3.4 new infections would have been expected if existing infection conferred no protection from superinfection. Adjusted for risk behaviors, the estimated relative risk of superinfection compared with initial infection was therefore 0.0 (95% confidence interval, 0.00, 0.79; P = 0.02), indicating that existing infection conferred a statistically significant level of protection against superinfection with an HIV-1 strain of the same subtype, which was between 21 and 100%.
authors.affiliation: Blood Systems Research Institute, University of California, San Francisco, San Francisco, California, USA.
authors.forename: Rose
authors.initials: R
authors.lastname: Tsui
authors.forename: Belinda L
authors.initials: BL
authors.lastname: Herring
authors.forename: Jason D
authors.initials: JD
authors.lastname: Barbour
authors.forename: Robert M
authors.initials: RM
authors.lastname: Grant
authors.forename: Peter
authors.initials: P
authors.lastname: Bacchetti
authors.forename: Alex
authors.initials: A
authors.lastname: Kral
authors.forename: Brian R
authors.initials: BR
authors.lastname: Edlin
authors.forename: Eric L
authors.initials: EL
authors.lastname: Delwart
mesh_terms: D000328:Adult; D005260:Female; D015686:Gene Products, env / Q000235:genetics; D015683:Gene Products, gag / Q000235:genetics; D015696:Gene Products, tat / Q000235:genetics; D015488:HIV Antigens / Q000235:genetics; D015658:HIV Infections / Q000175:diagnosis* / Q000821:virology; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D015819:Substance Abuse, Intravenous / Q000150:complications*; D015163:Superinfection; D013997:Time Factors; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; D054322:tat Gene Products, Human Immunodeficiency Virus
chemical_list: D015686:Gene Products, env; D015683:Gene Products, gag; D015696:Gene Products, tat; D015488:HIV Antigens; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C054858:p17 protein, Human Immunodeficiency Virus Type 1; D054322:tat Gene Products, Human Immunodeficiency Virus