Biomedical subjects

Volkan Ozenci

Publications and source records attributed to Volkan Ozenci.

7 recordsLinked to original sources

PubMed2025

Global guideline for the diagnosis and management of candidiasis: an initiative of the ECMM in cooperation with ISHAM and ASM.

Candida species are the predominant cause of fungal infections in patients treated in hospital, contributing substantially to morbidity and mortality. Candidaemia and other forms of invasive candidiasis primarily affect patients who are immunocompromised or critically ill. In contrast, mucocutaneous forms of candidiasis, such as oral thrush and vulvovaginal candidiasis, can occur in otherwise healthy individuals. Although mucocutaneous candidiasis is generally not life-threatening, it can cause considerable discomfort, recurrent infections, and complications, particularly in patients with underlying conditions such as diabetes or in those taking immunosuppressive therapies. The rise of difficult-to-treat Candida infections is driven by new host factors and antifungal resistance. Pathogens, such as Candida auris (Candidozyma auris) and fluconazole-resistant Candida parapsilosis, pose serious global health risks. Recent taxonomic revisions have reclassified several Candida spp, potentially causing confusion in clinical practice. Current management guidelines are limited in scope, with poor coverage of emerging pathogens and new treatment options. In this Review, we provide updated recommendations for managing Candida infections, with detailed evidence summaries available in the appendix.

Humans↗

PubMed2006

A short-term dietary supplementation with high doses of vitamin E increases NK cell cytolytic activity in advanced colorectal cancer patients.

Cancer patients with advanced disease display signs of immune suppression, which constitute a major obstacle for effective immunotherapy. Both T cells and NK cells are affected by a multitude of mechanisms of which the generation of reactive oxygen species is of major importance. Therefore, we hypothesized that two weeks of high-dose treatment with the anti-oxidant vitamin E may enhance NK cell function in cancer patients by protecting from oxidative stress. Seven patients with colorectal cancer (Dukes stage C and D) received a daily dose of 750 mg of vitamin E during a period of two weeks and the function, phenotype and receptor expression of NK cells were analyzed. The short-term vitamin E treatment significantly improved NK cell cytolytic activity in six out of the seven patients analyzed. The increased NK cell activity in patients' PBMC was not due to increased numbers of NK cells or an increase in the proportion of the CD56(dim) NK cell subpopulation. Furthermore, neither an increased perforin expression nor an enhanced ability of NK cells to produce IFN-gamma was observed as a result of vitamin E treatment. Finally, vitamin E treatment was associated with a minor, but consistent, induction of NKG2D expression in all patients analyzed. In conclusion, this pilot study demonstrates that vitamin E may boost NK cell function in patients with colorectal cancer. Further studies are warranted to explore the potential of vitamin E as an adjuvant for immunotherapy against cancer and to determine the underlying mechanism(s) behind vitamin E induced NK cell activation.

Antioxidants↗

PubMed2006

CD4+CD25high T cells are enriched in the tumor and peripheral blood of prostate cancer patients.

In this study, we investigated whether CD4+CD25high regulatory T cells (Treg) are increased in the tumor tissue and peripheral blood of early-stage prostate cancer patients undergoing prostatectomy. We show that the prevalence of CD4+CD25high T cells inside the prostate was significantly higher in the tumor compared with benign tissue from the same prostate. Furthermore, the frequency of CD4+CD25high T cells in peripheral blood was significantly higher in prostate cancer patients compared with normal donors. A proportion of the CD4+CD25high T cells was also shown to be glucocorticoid-induced TNF receptor, ICOS, and FOXP3 positive. Moreover, CD4+CD25+ T cells from blood and supernatants from cultured prostate tumor tissue samples exhibited immunosuppressive function in vitro. Furthermore, supernatants from cultured prostate tissue samples and prostate cancer ascites fluid induced migration of CD4+CD25+ T cells and were shown to contain the regulatory T cell chemokine CCL22 by ELISA. Our findings indicate that Tregs are an important cellular component of early-stage prostate tumors, and thus new therapeutic strategies aimed at inhibition or depletion of Tregs may improve prostate cancer immunotherapy.

Aged↗

PubMed2005

Presence and specificity of tumor associated lymphocytes from ascites fluid in prostate cancer.

BACKGROUND: In the present study, we had the rare opportunity to study immunological responses of TAL from ascites fluid in a patient with hormone-refractory prostate cancer. METHODS: We evaluated tumor antigen-specific T-cell responses, induced by either prostate specific antigen (PSA) pulsed dendritic cells (DCs) or PSA peptides, in TAL and peripheral blood lymphocytes. RESULTS: DC stimulation with PSA protein induced recognition of naturally processed PSA epitopes by both blood and ascites T cells. In contrast, only ascites T cells recognized the PSA-3 peptide, after stimulation with PSA-pulsed DCs or peptides. Finally, although IFNgamma secreting T cells were detectable in both blood and ascites by ELISPOT, multiplex cytokine assay detected the presence of predominantly Th2 cytokines. CONCLUSIONS: Although tumor antigen-specific TAL were detected in ascites fluid, these cells were producing immunosuppressive cytokines which may contribute to tumor escape from recognition and/or destruction by the immune system.

Ascitic Fluid↗

PubMed2004

Splenic denervation suppresses mRNA gene expression and protein production of IL-1beta and IL-6 by peritoneal macrophages in both Trypanosoma brucei brucei-infected and non-infected rats.

OBJECTIVE: To test the hypothesis that the nervous system participates in modulating the immune response during experimental African trypanosomiasis caused by Trypanosoma brucei brucei. METHODS AND RESULTS: Using in situ hybridization and immunochemistry, we studied the effects of splenic sympathectomy on mRNA gene expression and protein production of IL-1beta and IL-6 in splenic and peritoneal macrophages (PMPhi) of Sprague-Dawley rats infected with T. brucei brucei and non-infected rats. The enhancements of mRNA gene expression and production of IL-1beta and IL-6 by peritoneal macrophages were significantly suppressed by the splenic sympathectomy in both infected and non-infected rats. CONCLUSIONS: Our data indicate a probably stimulatory role of the sympathetic nervous system during the host immune response in both normal and T. brucei brucei-infected rats.

Animals↗

PubMed2002

Monocyte-derived dendritic cells express and secrete matrix-degrading metalloproteinases and their inhibitors and are imbalanced in multiple sclerosis.

Dendritic cells (DC) are antigen-presenting cells (APC) that most efficiently initiate and control immune responses. Migration processes of blood DC are crucial to exert their professional antigen-presenting functions. Matrix-degrading metalloproteinases (MMP) are proteolytic enzymes, which are considered to be key enzymes in extracellular matrix (ECM) turnover and mediators of cell migration. Tissue inhibitors of metalloproteinases (TIMP) are important regulators of MMP activity. Here we investigate whether blood monocyte-derived immature DC (iDC) and mature DC (mDC) express, produce and secrete functionally active MMP-1, -2, -3 and -9 and their inhibitors TIMP-1 and -2, and examine their involvement in multiple sclerosis (MS). On mRNA level, we observed high numbers of MMP-2 and TIMP-2 mRNA expressing iDC in MS. On protein level, high percentages of MMP-1, -2 and -9 expressing iDC by flow cytometry, and high MMP-1 secretion by Western blot together with high MMP-2 and -9 activities in iDC supernatants as studied with zymography were observed. Similarly, MS is associated with high percentages of MMP-2 and -3 and of TIMP-1 expressing mDC by flow cytometry together with high MMP-3 secretion and high MMP-9 activity in culture supernatants. Spontaneous migratory capacity of both iDC and mDC over ECM-coated filters was higher in MS compared to healthy controls (HC). In conclusion, blood monocyte-derived iDC and mDC express, produce and secrete several MMP and TIMP. Alterations in these molecules as observed in MS may be functionally important for DC functioning.

Adult↗

PubMedDate not supplied

Immune monitoring in a phase 1 trial of a PSA DNA vaccine in patients with hormone-refractory prostate cancer.

Prostate cancer remains a leading cause of cancer illness and death among men in Europe. No curative treatment exists when the disease has spread beyond the prostate. Immunotherapy with DNA vaccines has emerged as a potential therapeutic approach for the induction of antitumor specific cytotoxic T lymphocytes. In this study six patients with hormone-refractory prostate cancer were monitored for their ability to mount PSA-specific cellular responses after receiving a pVAX/PSA DNA vaccine (patients 1-3, 100 microg; patients 7-9, 900 microg) with recombinant GM-CSF and IL-2 as adjuvants. IFNgamma ELISPOT showed that naturally processed PSA protein and PSA peptides are recognized by T cells in the blood of some prostate cancer patients after a PSA DNA vaccine. Analysis of other cytokines showed the production of IL-4 and IL-6 but importantly did not show an increase in the number of IL-10-producing cells after vaccination in any of the patients. The authors conclude that a pVAX/PSA DNA vaccine can induce PSA-specific cellular immune responses in patients with hormone-refractory prostate cancer, thus emphasizing the potential for PSA as a target molecule for the immunotherapy of prostate cancer.

Antigen Presentation↗