Biomedical subjects

Frank De Wolf

Publications and source records attributed to Frank De Wolf.

3 recordsLinked to original sources

PubMed2004

Virologic and immunologic response to highly active antiretroviral therapy in indigenous and nonindigenous HIV-1-infected patients in the Netherlands.

OBJECTIVE: To compare the results of antiretroviral treatment (highly active antiretroviral therapy [HAART]) in indigenous Dutch (ID) and nonindigenous HIV-1-infected patients in Amsterdam, the Netherlands. We focused on the largest groups of nonindigenous people visiting our outpatient clinic: patients from other industrialized countries (western), from Surinam/Netherlands Antilles (SNA), and from sub-Saharan Africa (SSA). DESIGN: Retrospective cohort analysis of 692 therapy-naive HIV-1-positive individuals who visited our outpatient clinic for the first time between July 1, 1996 and December 31, 2001. METHODS: We compared the groups at the time of their first visit to our clinic; at the start of HAART; and according to the virological, immunologic, and clinical treatment response during the 96 weeks after the start of HAART. RESULTS: Of the patients starting antiretroviral therapy, 362 were ID, 84 were western, 72 were from SNA, and 110 were from SSA. SNA and SSA patients had a lower CD4 cell count at first visit (ID = 330 cells/mm(3), western = 330 cells/mm(3), SNA = 250 cells/mm(3), and SSA = 170 cells/mm(3); P = 0.0002). Treatment in SNA and SSA patients was also started at a lower CD4 cell count, but the plasma HIV-1 RNA level was comparable. After the start of HAART, a similar rise in CD4 cell count was seen in the 4 groups (P = 0.33), but the baseline difference in CD4 cell count remained present during the follow-up period of 96 weeks. After adjusting for variables potentially influencing treatment outcome, the proportion of patients not reaching a plasma HIV-1 RNA level <400 copies/mL was not different for the 4 groups in contrast to the percentage not reaching a plasma HIV-1 RNA level <50 copies/mL (at 48 weeks: ID = 4.8%, western = 27.5%, SNA = 23.1%, and SSA = 24.2%; P = 0.017 over the 96-week time period). After the start of HAART, nonindigenous patients also more often had progression to Centers for Disease Control and Prevention (CDC) stage C or died (P = 0.006). CONCLUSIONS: In nonindigenous patients, treatment with HAART was equally successful in terms of the increase in CD4 cell count but was substantially less effective in achieving a plasma HIV-1 RNA level below 50 copies/mL. Further investigations should explore differences in adherence and pharmacokinetics in these patient groups.

Adult↗

PubMed2002

Antigen-driven T-cell turnover.

A mathematical model is developed to characterize the distribution of cell turnover rates within a population of T lymphocytes. Previous models of T-cell dynamics have assumed a constant uniform turnover rate; here we consider turnover in a cell pool subject to clonal proliferation in response to diverse and repeated antigenic stimulation. A basic framework is defined for T-cell proliferation in response to antigen, which explicitly describes the cell cycle during antigenic stimulation and subsequent cell division. The distribution of T-cell turnover rates is then calculated based on the history of random exposures to antigens. This distribution is found to be bimodal, with peaks in cell frequencies in the slow turnover (quiescent) and rapid turnover (activated) states. This distribution can be used to calculate the overall turnover for the cell pool, as well as individual contributions to turnover from quiescent and activated cells. The impact of heterogeneous turnover on the dynamics of CD4(+) T-cell infection by HIV is explored. We show that our model can resolve the paradox of high levels of viral replication occurring while only a small fraction of cells are infected.

Antigens, Viral↗

PubMed2002

Viral replication under combination antiretroviral therapy: a comparison of four different regimens.

A mathematical model of the interaction among CD4+ T-cells, HIV-1, and antiretroviral drugs was fitted to the viral load decline following initiation of combination therapy to estimate differences in the residual reproductive capacity of virus (R(0)) in the average patient in each group. Four regimens were studied: 12 patients on 5-drug nucleoside reverse transcriptase inhibitor (NRTIs), nonnucleoside reverse transcriptase inhibitor (NNRTIs) and protease inhibitor (PI)-containing combination therapy, 11 patients on PI-containing triple therapy, 10 patients on double NRTI therapy, and 10 patients on NNRTI-containing triple therapy. Model fits were used to estimate R(0). The NNRTI-containing triple therapy and the 5-drug regimen blocked viral replication to the greatest extent (R(0) = 0.85; 95% confidence interval [CI], 0.79-0.91; and 0.90, 95% CI, 0.82-0.98, respectively), with the former being significantly better than the PI-containing triple regimen (R(0) = 0.98; 95% CI, 0.92-1.03; p =.007). Both the NNRTI-containing and the 5-drug regimen, as well as the PI-containing triple therapy, were significantly better at blocking viral replication than the double NRTI therapy (R(0) = 1.04; 95% CI, 1.0-1.07). Measurement of viral load after approximately 7 days provided the most accurate measure of the degree of viral suppression induced by a given drug regimen.

Adult↗