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James Luyendyk

Publications and source records attributed to James Luyendyk.

2 recordsLinked to original sources

Oncogenes, trousseau syndrome, and cancer-related changes in the coagulome of mice and humans.

Cancer is often associated with venous thrombosis, a phenomenon that was first described by Trousseau in 1865 (Trousseau syndrome). Recent studies have begun to explain how oncogenic events may deregulate the hemostatic system. For instance, activated oncogenes (K-ras, EGFR, PML-RARalpha, and MET) or inactivated tumor suppressors (e.g., 53 or PTEN) may increase the risk of thrombosis by inducing the expression of tissue factor, a potent procoagulant molecule, and plasminogen activator inhibitor-1, a fibrinolysis inhibitor. In a more complex clinical reality, transforming genes may often act in concert with numerous epigenetic factors, including hypoxia, inflammation, anticancer therapy, contact between blood and metastatic cancer cells, and emission of procoagulant vesicles from tumors and their stroma into the circulation. To add to mechanistic insights gained from mouse models, which may not fully phenocopy human Trousseau syndrome, we suggest that valuable clues to progression and thrombosis risk may be obtained by monitoring multiple hemostatic variables in cancer patients ("coagulomics").

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Antigen-presenting cell function during Plasmodium yoelii infection.

Antigen-presenting cells (APC) play a key role in orchestrating immune responses. T-cell proliferative responses are inhibited during the erythrocyte stages of malaria infection, and a number of studies have suggested that APC are responsible for this phenomenon. In the present studies we examine individual components of the T-cell-activating function of APC: expression of costimulatory and major histocompatibility complex (MHC) class II proteins, the ability to process and present antigen to T cells, and the ability to support cytokine production. We find that during the acute phases of Plasmodium yoelii erythrocyte stage infection, APC upregulate the expression of class II MHC and CD80, maintain expression of CD86, process and present antigen, and support gamma interferon production. However the CD11b(+) subpopulation produces a soluble factor or factors that specifically inhibit interleukin-2 (IL-2) production by responding CD4 T cells. This factor is distinct from prostaglandin E(2), NO, or transforming growth factor beta. The data suggest that IL-2 suppression observed during malaria infection is not due to functional defects of APC but is triggered by production of a factor(s) that actively suppresses production of IL-2 by T cells.

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