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Biomedical subjects

Rui M M Victorino

Publications and source records attributed to Rui M M Victorino.

6 recordsLinked to original sources
PubMed2006

Increased frequency of circulating CCR5+ CD4+ T cells in human immunodeficiency virus type 2 infection.

CCR5 expression determines susceptibility to infection, cell tropism, and the rate of human immunodeficiency virus type 1 (HIV-1) disease progression. CCR5 is also considered the major HIV-2 coreceptor in vivo, in spite of broad coreceptor use in vitro. Here we report a significantly increased proportion of memory-effector CD4 T cells expressing CCR5 in HIV-2-infected patients correlating with CD4 depletion. Moreover, HIV-2 proviral DNA was essentially restricted to memory-effector CD4, suggesting that this is the main target for HIV-2. Similar levels of proviral DNA were found in the two infection categories. Thus, the reduced viremia and slow rate of CD4 decline that characterize HIV-2 infection seem to be unrelated to coreceptor availability.

Adult↗
PubMed2003

Brachiocephalic vein thrombosis associated with Crohn's disease.

An association between macrovascular thrombosis and idiopathic inflammatory bowel disease has been described, although very few well-documented cases have been published. We report on a 39-year-old woman who presented with right hemifacial and upper limb edema that was shown to be due to an extensive right brachiocephalic vein thrombosis, diagnosed by magnetic resonance angiography. Laboratory findings suggested malabsorption, and a diagnosis of Crohn's disease was established. Moreover, elevation of the plasminogen activator inhibitor system was identified. This represents the first description of a spontaneous thrombosis in a patient with Crohn's disease involving the intrathoracic venous system and raises the possibility of impaired fibrinolysis being involved in the etiopathogenesis of this complication.

Adult↗
PubMed2002

CD4 T cell depletion is linked directly to immune activation in the pathogenesis of HIV-1 and HIV-2 but only indirectly to the viral load.

The causal relationships among CD4 cell depletion, HIV replication, and immune activation are not well understood. HIV-2 infection, "nature's experiment" with inherently attenuated HIV disease, provides additional insights into this issue. We report the finding that in HIV-2 and HIV-1 patients with a comparable degree of CD4 depletion the imbalance in the relative sizes of the naive and memory T cell populations and the up-regulation of CD4 and CD8 cell activation markers (HLA-DR, CD38, CD69, Fas molecules) are similar, even though the viral load in the plasma of HIV-2-infected patients is two orders of magnitude lower than in HIV-1 patients and HIV-2 patients are known to have slower rates of CD4 T cell decline and a better clinical prognosis. Moreover, we found a similar increase in the frequency of cycling CD4 T cells (Ki67+), which was in strong correlation with the expression of activation markers. Finally, the level of T cell anergy, as assessed by the proliferative responses to CD3 stimulation and to a panel of microbial Ags, proved to be comparable in HIV-1 and HIV-2 patients with a similar degree of CD4 depletion despite large differences in viral load. Our data are consistent with a direct causal relationship between immune activation and CD4 cell depletion in HIV disease and an only indirect relation of these parameters to the virus replication rate. Invoking the concept of proximal immune activation and virus transmission, which links efficient transmission of virus to local cell activation and proliferation in response to Ags and inflammation, we propose an integrative interpretation of the data and suggest that strongly elevated immune activation induces CD4 cell depletion and not vice versa, with potential implications for the choice of treatment strategies.

Biomarkers↗