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Dual superinfection identified in high-risk HIV-infected patient
  Last Updated: 2006-06-05 15:41:42 -0400 (Reuters Health)
By Will Boggs, MD
NEW YORK (Reuters Health) - Dual superinfection and possible recombination have been identified in an HIV-infected patient who continued to practice high-risk behaviors after the initial infection, according to a report by investigators in Spain.
Although superinfection has been observed after primary infection with HIV, the authors explain, most cases have developed shortly after the primary infection. This case occurred 12 years after primary infection in a patient who continued unsafe intravenous drug abuse and unprotected sexual contacts.
Dr. Cecilio Lopez-Galindez and colleagues from Instituto de Salud Carlos III, Madrid, analyzed viral quasispecies in pol and env genes in several plasma samples from this patient to investigate the possibility of superinfection. The findings are published in the May 1 issue of the Journal of Acquired Immune Deficiency Syndromes.
Phylogenetic analysis of the reverse transcriptase region of the pol gene showed only one cluster in samples from 1994 and 1998 and April 1999, the authors report, but two new clusters were detected in the July 1999 sample.
Similarly, phylogenetic analysis of the first 240 nucleotides of the env gene showed three distinct clusters that differed by 14.3% to 18.2%, the results indicate.
"We could not definitely identify if the presence of the two new strains in the June 1999 sample was due to two independent infection events or to a dual superinfection," the investigators write. "However, the short time between the presence of only one strain in April 1999 and, 3 months later, the detection of three strains favors dual coinfection."
"From a virological point of view," the authors conclude, "this work reports the first case of a dual superinfection that, together with a recombination event between the infecting strains, provides evidence for the extremely high viral genetic diversity and complexity that can be observed in HIV-1 in vivo infections."
"From the clinical perspective," the researchers add, "we have demonstrated that superinfection (with > 1 strain) could occur at any moment during the infection. These results highlight the importance of reducing risky behaviors in HIV-1-infected individuals."
"High risk practices could result in re-infection with one or multiple viruses, which could present resistance mutations and then could compromise antiretroviral treatment (our patient was re-infected with one virus showing AZT and 3TC resistance mutations)," Dr. Lopez-Galindez told Reuters Health.
"Virological follow-up of patients with multiple exposures could give important information on the pathogenesis of HIV-1 infection," Dr. Lopez-Galindez added.
J Acquir Immune Defic Syndr 2006;42:12-18.
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