Strong evidence that people with HIV can become re-infected, or super-infected, with serious consequences for disease progression, was presented at the Seventh Conference on Retroviruses today in San Francisco.
Dr Jonathan Angel of Ottawa Hospital described the case of a man who a experienced a sudden and dramatic fall in his CD4 count after eight years of relative non-progression and very low viral load. In the space of six months during 1998 his CD4 count fell by more than 400 cells/mm3 and his viral load surged from around 20,000 copies/mL to above 100,000 copies/mL. The patient failed to respond to protease inhibitor therapy and doctors began to investigate why.
The patient, a 40 year old gay man, suggested that he could have become re-infected during a relationship with a highly treatment-experienced man during the latter half of 1997. When virus samples from the two men were compared, along with a stored sample from 1989, it was discovered that regions of the reverse transcriptase and protease genes that don’t normally mutate bore a strong resemblance to each other. 12 samples from other patients at the clinic which served as controls did not show the same resemblance. The man had also developed mutations associated with 3TC resistance and protease inhibitor resistance, and insisted that he had taken no antiretroviral therapy apart from participating in a short trial of ribavirin in 1989.
Dr Angel told the meeting that these findings provide the strongest evidence yet for HIV-1 re-infection, with significant public health implications. Although re-infection after seroconversion has been demonstrated in chimpanzees, many people with HIV and clinicians have remained sceptical about the possibility of re-infection and its effects.
The Ottawa case joins a still unpublished Swedish case first presented in October 1998, describing a woman who acquired a protease-resistant virus from a sexual partner.
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Reference
Angel J et al. Documentation of HIV-1 superinfection and acceleration of disease progression. Abstract LB2, Seventh Conference on Retroviruses, 2000.