Biomedical subjects

Yoann Madec

Publications and source records attributed to Yoann Madec.

4 recordsLinked to original sources

PubMed2005

Spontaneous control of viral load and CD4 cell count progression among HIV-1 seroconverters.

OBJECTIVES: To identify factors associated with sustained undetectable viraemia after HIV-1 seroconversion in treatment-naive patients, and to describe concomitant CD4 cell count progression. METHODS: Seroconverters enrolled in CASCADE were assumed to control viraemia if at least two consecutive viral load measurements were < 400/500 copies/ml without treatment. Factors associated with undetectable viraemia were identified through a logistic regression. A joint model was used to describe simultaneously the CD4 cell count progression during and after that period and to identify factors associated with sustained undetectable viraemia. RESULTS: Of 2176 seroconverters, 145 (6.7%) spontaneously controlled viraemia. Women were more likely than men to achieve undetectable viraemia [adjusted odds ratio (OR), 2.12; 95% confidence interval (CI), 1.49-3.12] unlike patients who reported a symptomatic primary infection (adjusted OR, 0.58; 95% CI, 0.36-0.94). AIDS and death rates were significantly lower in patients achieving undetectable viraemia than in the others. The median period of undetectable viraemia was 11.2 months; on average, CD4 cell counts remained stable during that period, and decreased with a mean rate of 5 cells/microl per month thereafter. High CD4 cell count at the beginning of undetectable viraemia and non-symptomatic primary infection favoured the preservation of undetectable viraemia. CONCLUSION: A small proportion of seroconverters appeared to be able to control HIV viraemia spontaneously, mostly those without seroconversion illness and within a few years following seroconversion; this is associated with the benefits of slower CD4 cell count decline and improved long-term prognosis. Such persons should be targeted for in depth investigation.

Acquired Immunodeficiency Syndrome↗

PubMed2005

HIV controllers: a homogeneous group of HIV-1-infected patients with spontaneous control of viral replication.

We identified a total 15 patients who have maintained undetectable plasma HIV RNA loads without antiretroviral treatment for >10 years from cohorts of 1300 and 1551 patients infected with human immunodeficiency virus (HIV). These 15 patients, whom we have referred to as "HIV controllers," are characterized by a low HIV DNA load in peripheral blood mononuclear cells and by a strong HIV-specific immune response.

Adult↗

PubMed2005

Undetectable viremia without antiretroviral therapy in patients with HIV seroconversion: an uncommon phenomenon?

BACKGROUND: The objective of this study was to identify the frequency and characteristics of patients with human immunodeficiency virus (HIV) infection who had spontaneously achieved viremia below the detection limit of either 400 or 500 copies/mL (depending on the test used) and to describe the duration of undetectable viremia without antiretroviral therapy (ART). METHODS: In the French Agence Nationale de Recherches sur le SIDA SEROCO cohort, 426 patients with HIV seroconversion (i.e., seroconverters) enrolled between 1988 and 1995 had serial measurement of HIV RNA levels during follow-up (with a cutoff date of 31 December 2002). Factors that distinguished those patients who had spontaneously achieved undetectable viremia (> or =2 consecutive viral loads <400 or <500 copies/mL while not receiving ART) were identified by logistic regression. A Cox model was used to estimate the predictive value of factors related to the duration of undetectable viremia. RESULTS: Undetectable viremia had been spontaneously achieved in 36 of 426 seroconverters. Women (adjusted odds ratio [aOR], 2.44; 95% confidence interval [CI], 1.03-5.80) and subjects with baseline HIV RNA level < or =3.76 log10 copies/mL (aOR, 0.31; 95% CI, 0.11-0.82), baseline HIV DNA level < or =2.61 log10 copies/mL (aOR, 0.14; 95% CI, 0.04-0.44), and high baseline CD4+ cell count (aOR, 1.18 for each 100 cells/mm3; 95% CI, 1.03-1.35]) were more likely to have achieved undetectable viremia. The sustainability of this phenomenon (median duration, 11.9 months; range, 4.6-62.8 months) was associated with low baseline HIV DNA and RNA levels. CONCLUSIONS: Achieving undetectable viremia without ART was not rare, because 6.7% of seroconverters still had a viral load of <400 or <500 copies/mL 5 years after seroconversion. These data should be considered when assessing virologic outcome for patients who interrupt highly active ART initiated during primary infection.

Adolescent↗

PubMed2004

First passage time problem for a drifted Ornstein-Uhlenbeck process.

We consider a continuous stochastic process defined as a drifted Ornstein-Uhlenbeck, for which the first passage time is of interest. The process being non-homogeneous, the first passage time probability density function cannot be found analytically, but numerical methods enable to find its estimate. Estimating the first passage time implies solving an unsteady convection-diffusion equation, with variable coefficients, and we use an implicit Euler scheme to solve it. This work is applied to simulated data, and the continuous process is inspired from recent work on biological marker modelling for HIV-positive patients. The first passage time probability density function can be useful to compare the marker progression in different groups. Numerical results show that the first passage time is highly dependent from the process perturbation, and is then more relevant than methods not considering the stochastic process directly to compare the progression.

Biomarkers↗