Strong evidence for re-infection from Canada

Keith Alcorn
Estimated reading time 2 minutes
This article is more than 24 years old.

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.

Glossary

reinfection

In HIV, synonym for superinfection. In hepatitis C, used when someone who has been cured of the virus is infected with hepatitis C again.

disease progression

The worsening of a disease.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

reverse transcriptase

A retroviral enzyme which converts genetic material from RNA into DNA, an essential step in the lifecycle of HIV. Several classes of anti-HIV drugs interfere with this stage of HIV’s life cycle: nucleoside reverse transcriptase inhibitors and nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). 

seroconversion

The transition period from infection with HIV to the detectable presence of HIV antibodies in the blood. When seroconversion occurs (usually within a few weeks of infection), the result of an HIV antibody test changes from HIV negative to HIV positive. Seroconversion may be accompanied with flu-like symptoms.

 

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.

Click here to read stories posted throughout the week from the Seventh Retroviruses Conference

Click here for conference abstracts and video/audio feed of conference presentations.

Detailed summaries of each days' proceedings by leading clinicians are available at Medscape HIV/AIDS

Reference

Angel J et al. Documentation of HIV-1 superinfection and acceleration of disease progression. Abstract LB2, Seventh Conference on Retroviruses, 2000.

Print