You are here
HIGH RATE OF DISEASE PROGRESSION IN UNTREATED HIV-2 INFECTION
Joakim Esbjörnsson1, Fredrik Månsson2, Anders Kvist3, Zacarias J. da Silva4, Jacob Lindman3, Angelica Palm3, Marianne Jansson3, Patrik Medstrand3, Hans Norrgren3
1Univ of Oxford, Oxford, UK,2Lund Univ, Malmö, Sweden,3Lund Univ, Lund, Sweden,4LNSP, Bissau, Guinea-Bissau
Compared with HIV-1, HIV-2 is considered to be more benign and without severe pathogenic consequences throughout the disease course for the majority of infected individuals. However, conclusive survival data from cohorts with long follow-up and estimated time of infection is lacking.
We followed 312 participants infected with HIV-1 or HIV-2 after enrollment in a cohort from Guinea-Bissau with 23 years of follow-up, according to the time from infection to AIDS or HIV-related mortality, and measures of T-cell dynamics. Weibull distributions were fitted to the survival data to assess the hypothesis of heterogeneous disease courses among HIV-2 infected individuals.
The median times to AIDS and mortality were 14.3 years (confidence interval [CI], 10.7-18.0) and 15.6 years (CI, 12.0-19.2) for HIV-2 infected participants, and 6.2 years (CI, 5.4-7.1) and 8.2 years (CI, 7.6-8.8) for HIV-1 infected individuals (p<0.001 for both comparisons, Log rank test). The Weibull analysis showed that HIV-2 infected individuals followed a uniform disease trajectory similar to HIV-1 infected individuals, but at a 53% lower acceleration rate. The proportion of HIV-2 infected individuals under risk at the end of follow-up was 17.5%, further supporting that the majority of HIV-2 infected individuals will progress to AIDS and HIV-related mortality if followed long enough. Linear mixed model analyses of T-cell dynamics showed both higher levels of CD4+ T-cell counts early after infection (p<0.001, Likelihood Ratio Test [LRT]) and slower decline rates among HIV-2 compared with HIV-1 infected individuals (p=0.028, LRT). Finally, CD4+ T-cell levels at clinical AIDS was higher in HIV-2 compared with HIV-1 infected individuals (18.2% vs. 8.2%, p<0.001, 2-tailed Mann-Whitney U Test).
Our results contradicts the common assumption that the majority of HIV-2 infected individuals remain long-term-non-progressors and suggest that, similar to HIV-1 infection, HIV-2 infection will result in disease development if followed long enough. This suggests that early treatment initiation would be beneficial also for HIV-2 infected individuals.