Differences in HIV Natural History among African and Non-African Seroconverters in Europe and Seroconverters in Sub-Saharan Africa

Introduction It is unknown whether HIV treatment guidelines, based on resource-rich country cohorts, are applicable to African populations. Methods We estimated CD4 cell loss in ART-naïve, AIDS-free individuals using mixed models allowing for random intercept and slope, and time from seroconversion to clinical AIDS, death and antiretroviral therapy (ART) initiation by survival methods. Using CASCADE data from 20 European and 3 sub-Saharan African (SSA) cohorts of heterosexually-infected individuals, aged ≥15 years, infected ≥2000, we compared estimates between non-African Europeans, Africans in Europe, and Africans in SSA. Results Of 1,959 (913 non-Africans, 302 Europeans - African origin, 744 SSA), two-thirds were female; median age at seroconversion was 31 years. Individuals in SSA progressed faster to clinical AIDS but not to death or non-TB AIDS. They also initiated ART later than Europeans and at lower CD4 cell counts. In adjusted models, Africans (especially from Europe) had lower CD4 counts at seroconversion and slower CD4 decline than non-African Europeans. Median (95% CI) CD4 count at seroconversion for a 15–29 year old woman was 607 (588–627) (non-African European), 469 (442–497) (European - African origin) and 570 (551–589) (SSA) cells/µL with respective CD4 decline during the first 4 years of 259 (228–289), 155 (110–200), and 199 (174–224) cells/µL (p<0.01). Discussion Despite differences in CD4 cell count evolution, death and non-TB AIDS rates were similar across study groups. It is therefore prudent to apply current ART guidelines from resource-rich countries to African populations

The response of tropical rainforests to drought : lessons from recent research and future prospects

Key message: we review the recent findings on the influence of drought on tree mortality, growth or ecosystem functioning in tropical rainforests. Drought plays a major role in shaping tropical rainforests and the response mechanisms are highly diverse and complex. The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical rainforests on the three continents. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. - Context: tropical rainforest ecosystems are characterized by high annual rainfall. Nevertheless, rainfall regularly fluctuates during the year and seasonal soil droughts do occur. Over the past decades, a number of extreme droughts have hit tropical rainforests, not only in Amazonia but also in Asia and Africa. The influence of drought events on tree mortality and growth or on ecosystem functioning (carbon and water fluxes) in tropical rainforest ecosystems has been studied intensively, but the response mechanisms are complex.- Aims: herein, we review the recent findings related to the response of tropical forest ecosystems to seasonal and extreme droughts and the current knowledge about the future of these ecosystems. - Results: this review emphasizes the progress made over recent years and the importance of the studies conducted under extreme drought conditions or in through-fall exclusion experiments in understanding the response of these ecosystems. It also points to the great diversity and complexity of the response of tropical rainforest ecosystems to drought. - Conclusion: the numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical forest regions. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance

Serum HIV-1 RNA levels and time to development of AIDS in the multicenter hemophilia cohort study

Objective.-To determine if the long-term incidence of the acquired immunodeficiency syndrome (AIDS) is related to human immunodeficiency virus type 1 (HIV-1) RNA levels measured early in HIV-1 infection. Design.-Epidemiologic cohort study. Setting.-Five hemophilia treatment centers in the United States. Subjects.-A total of 165 subjects with hemophilia and HIV-1 infection (age at HIV-1 seroconversion, 1-66 years) followed from 1979 to 1995. Methods.-The HIV-1 RNA level was measured by polymerase chain reaction over a range of 200 to 1 million or more HIV-1 RNA copies/mL. in archived serum specimens collected 12 to 36 months (median, 27 months) after the estimated date of HIV-1 seroconversion. Kaplan-Meier methods were used to examine the risk of AIDS and proportional hazards models were used to estimate relative hazards. Results.-The HIV-1 RNA values were similar in subjects younger than 17 years at seroconversion (median, 5214 copies/mL) and those 18 to 34 years old (median, 4693 copies/mL), but higher in those 35 years or older (median, 12 069 copies/mL) (P=.02 compared with each younger group). At 10 years after seroconversion, the proportions of subjects with AIDS were 72% among subjects with 100 000 or more HIV-1 RNA copies/mL measured 12 to 36 months after HIV-1 seroconversion (n=9), 52% among subjects with 10 000 to 99 999 copies/mL (n=55), 22% among subjects with 1000 to 9999 copies/mL (n=82), and 0% among subjects with fewer than 1000 copies/mL (n=19) (P Conclusions.-The HIV-1 RNA level during early chronic HIV-1 infection is a strong, age-independent predictor of clinical outcome; low revels define persons with a high probability of long-term AIDS-free survival

Serum HIV-1 RNA levels and time to development of AIDS in the multicenter hemophilia cohort study

Objective.-To determine if the long-term incidence of the acquired immunodeficiency syndrome (AIDS) is related to human immunodeficiency virus type 1 (HIV-1) RNA levels measured early in HIV-1 infection. Design.-Epidemiologic cohort study. Setting.-Five hemophilia treatment centers in the United States. Subjects.-A total of 165 subjects with hemophilia and HIV-1 infection (age at HIV-1 seroconversion, 1-66 years) followed from 1979 to 1995. Methods.-The HIV-1 RNA level was measured by polymerase chain reaction over a range of 200 to 1 million or more HIV-1 RNA copies/mL. in archived serum specimens collected 12 to 36 months (median, 27 months) after the estimated date of HIV-1 seroconversion. Kaplan-Meier methods were used to examine the risk of AIDS and proportional hazards models were used to estimate relative hazards. Results.-The HIV-1 RNA values were similar in subjects younger than 17 years at seroconversion (median, 5214 copies/mL) and those 18 to 34 years old (median, 4693 copies/mL), but higher in those 35 years or older (median, 12 069 copies/mL) (P=.02 compared with each younger group). At 10 years after seroconversion, the proportions of subjects with AIDS were 72% among subjects with 100 000 or more HIV-1 RNA copies/mL measured 12 to 36 months after HIV-1 seroconversion (n=9), 52% among subjects with 10 000 to 99 999 copies/mL (n=55), 22% among subjects with 1000 to 9999 copies/mL (n=82), and 0% among subjects with fewer than 1000 copies/mL (n=19) (P&lt;.001). The age-adjusted relative hazard for AIDS for subjects with 10 000 or more copies/mL was 14.3 (95% confidence interval, 1.9-105.6) compared with subjects with fewer than 1000 copies/mL. Conclusions.-The HIV-1 RNA level during early chronic HIV-1 infection is a strong, age-independent predictor of clinical outcome; low revels define persons with a high probability of long-term AIDS-free survival