Biomedical subjects

Luca Piacentini

Publications and source records attributed to Luca Piacentini.

6 recordsLinked to original sources

PubMed2007

Immune activation and normal levels of endogenous antivirals are seen in healthy adolescents born of HIV-infected mothers.

Immunological analyses performed in healthy adolescents born of HIV-infected (seroreverters) or healthy mothers (healthy controls; HC) showed that immune activation and a skewing of postthymic differentiation are present in adolescent seroreverters. In-utero HIV exposure results in long-lasting imprinting on the immune system. Alternatively, an immune response naturally more prone to activation could prevent vertical infection. Endogenous antivirals (APOBEC, TRIM5alpha) were comparable in seroreverters and HC, and might not play a role in resistance to vertical HIV infection.

Adolescent↗

PubMed2006

Thalidomide in the treatment of chronic hepatitis C unresponsive to alfa-interferon and ribavirin.

Immunomodulation of thalidomide is represented by the antiinflammatory effect through inhibition of tumor necrosis factor alpha and costimulatory effect on human CD8+ T cells. We investigated the efficacy and safety of a 24-wk course of thalidomide at a dosage of 200 mg/day in eight patients with HCV chronic hepatitis nonresponders to interferon alpha plus ribavirin. We observed a significant mean decrease of serum aminotransferases and gamma-glutamyltransferases of 39% and 61%, respectively (p = 0.017 and 0.02). Tumor necrosis factor-alpha in vitro production in mononuclear cells decreased with thalidomide in all the subjects (p = 0.028). Perforin- and granzyme-specific mRNA expression increased under thalidomide without statistical significance. A positive correlation between biochemical and immunological parameters was observed with higher increase of granzyme and perforin values in patients showing reduction of aminotransferases. Finally upregulation of T-helper 1 cytokine expression as mean interferon gamma/IL-10 ratio was evidenced. Thalidomide was well tolerated. In conclusion, thalidomide was able to reduce liver enzymes in six out of eight patients with chronic hepatitis C and to reduce tumor necrosis factor alpha production, representing a promising new approach for the treatment of HCV infection.

Adult↗

PubMed2005

Decrease in pathology and progression of scrapie after immunisation with synthetic prion protein peptides in hamsters.

Effective therapy for prion diseases is currently unavailable. Recently, vaccination was shown to be effective in mouse models of a particular neurodegenerative conditions: Alzheimer's disease (AD). Here, we report that vaccination with synthetic oligopeptides homologous to the hamster (Mesocricetus auratus) prion protein augments survival time in animals infected intraperitoneally with 263K scrapie agent. For each hamster included in the study, prion-specific serum antibodies as well as deposition of pathological prion protein (PrP(res)), glial fibrillary acidic protein (GFAP), and mRNA expression for cytokines (TNF alpha, IL-1beta, IL-10) in brain tissues were evaluated. In immunized animals, increased survival after challenge was associated with a reduction of cerebral lesion, PrP deposition and GFAP expression; in these animals, anti-prion protein peptide antibody levels were increased, and the expression of pro-inflammatory cytokines (TNF alpha and IL-1beta) was reduced. Vaccination could be an effective therapeutic approach to postpone disease onset.

Amino Acid Sequence↗

PubMed2004

Granule-dependent mechanisms of lysis are defective in CD8 T cells of HIV-infected, antiretroviral therapy-treated individuals.

BACKGROUND: HIV-specific cytotoxic T-cell (CTL) responses are defective in HIV-infected patients undergoing antiretroviral therapy (ART). This defect has been attributed to the decreased antigenic burden secondary to ART-associated suppression of HIV-replication, and is responsible for the rebounds of viraemia that occur when patients interrupt therapy. CTL are stimulated by type 1 cytokines and can kill targets via granule-dependent (perforin and granzymes) and -independent (tumour necrosis factor-alpha, CD95) mechanisms. METHODS: Granule-dependent and granule-independent mechanisms of CTL killing, as well as type 1 cytokine production by CD4 T cells, were analysed in 57 chronically HIV-infected ART-treated or ART-untreated individuals. RESULTS: The results can be summarized as follows: the frequency of gp160 (env)-specific interferon-gamma-secreting CD8 T lymphocytes correlates positively with HIV viraemia in ART-treated and -untreated patients; Env-specific perforin- and granzymes-expressing CD8 T lymphocytes, and Env-stimulated perforin and granzymes mRNA, are reduced in ART-treated patients independently of HIV viral load and of type 1 cytokine production; tumour necrosis factor-alpha production is increased in ART-treated individuals; and Env-specific immature CD8+28+27+ cells are only marginally augmented in ART-treated patients, Similar results are observed in cytomegalovirus-specific CD8 T cells and peripheral blood mononuclear cells. CONCLUSIONS: A defect of CTL function that selectively affects the granule-dependent mechanisms of lysis is observed in ART-treated individuals. Because interferon-gamma production is higher in these patients, this could be a defect primarily involving CTL. These data suggest an independence of CD8 T-cell numbers and their lytic ability in HIV-infected, ART-receiving patients. Immunomodulants are needed to successfully treat HIV infection.

Adult↗

PubMed2003

IL-4 and CXCR4 upregulation in HIV-infected and uninfected individuals from Maharashtra-Mumbai.

We extended the investigation of the virus-host interaction in developing countries by analysing Indian HIV-infected and uninfected individuals from Maharashtra-Mumbai. Results showed that CXCR4 messenger RNA and surface expression, as well as IL-4 mRNA and T allele frequency at the -589 site in the IL-4 gene (high IL-4 production) were significantly increased in Indian compared with Italian individuals. Because IL-4 stimulates CXCR4 expression this observation could be explained by the higher frequency of the -589T IL-4 polymorphism.

CD4-Positive T-Lymphocytes↗

PubMed2002

B7-H1 is up-regulated in HIV infection and is a novel surrogate marker of disease progression.

The ligation of programmed death-ligand 1 (B7-H1) to T cells results in the preferential production of interleukin 10 (IL-10). We investigated if B7-H1 would be up-regulated in HIV infection, a disease characterized by increased IL-10 production, by measuring B7-H1, B7-1 (CD80), and B7-2 (CD86) expression and mRNA in 36 HIV-infected patients and in 22 healthy controls (HCs). Results showed that (1) B7-H1 expression and mRNA are augmented in cells of HIV patients; (2) increased IL-10 production in these patients is largely induced by B7-H1-expressing CD14(+) cells; (3) an inverse correlation is detected between B7-H1 expression and CD4 counts, whereas the up-regulation of B7-H1 is directly associated with HIV plasma viremia; (4) antiviral therapy results in the parallel down modulation of IL-10 production and B7-H1 expression/synthesis; and (5) B7-H1/CD80 and B7-H1/CD86 mRNA ratios are increased in peripheral blood mononuclear cells (PBMCs) of HIV patients compared with HCs. B7-H1 synthesis and expression are up-regulated in HIV infection, and the degree of dysregulation correlates with the severity of disease. Aberrant antigen presentation by antigen-presenting cells (APCs) that exhibit increased B7-H1 expression and IL-10 production in HIV infection could be responsible for T-lymphocyte unresponsiveness and loss of protective immunity. B7-H1 is a surrogate marker potentially involved in AIDS disease progression.

Antigens, CD↗