Study of the effects of Lemna minor extracts on human immune cell populations

OBJECTIVE: Lemna minor is a plant with a huge repertoire of secondary metabolites. The literature indicates that extracts of Lemna minor have antioxidant, antiradical, immunomodulatory and anti-inflammatory properties. The objective of the present study was to find a suitable technique to extract active compounds from this plant and verify whether these extracts have immunomodulatory activity. MATERIALS AND METHODS: We grew L. minor on a standard medium with Gamborg B5 and vitamins. We extracted compounds from the plant by maceration and decoction. The phytochemical profile of the extracts was characterized by chromatography, spectrophotometry, and spectroscopy. The extracts were tested on cultures of mononuclear cells from four human subjects. These cells were pulsed with carboxyfluorescein succinimidyl ester, grown in triplicate in standard culture medium without (control) and with increasing concentrations of Lemna extracts. Flow cytometry was used to evaluate cell death and proliferation of the total mononuclear cell population and of CD4+, CD8+, B cell and monocyte populations. RESULTS: The Lemna extracts were not cytotoxic and did not cause cell necrosis or apoptosis in immune cells. At low concentrations, they induced very limited proliferation of CD4+ cells within 48 hours. At high concentrations, they induced proliferation of CD8+ cells and B lymphocytes within 48 hours. CONCLUSIONS: Unfortunately, we failed to confirm any immunomodulatory activity of Lemna extracts. Growth and death rates of human immune cells were not significantly affected by adding Lemna extracts to the culture medium

Marked increase with age of type 1 cytokines within memory and effector/cytotoxic CD8+ T cells in humans: a contribution to understand the relationship between inflammation and immunosenescence

The ageing process is characterized by a progressive exhaustion of the na ̈ıve T cell reservoir that is accompanied by a compensatory expansion of effector/cytotoxic CD8þCD282 T cells. However, the origin and function of this subpopulation is not completely clarified. In this study, we examined the intracellular cytokine profile in purified CD8þ T cells obtained from 29 healthy subjects of different ages. Type 1 (IFN-g IL-2 and TNF-a) and type 2 (IL-4, IL-6 and IL-10) cytokines were determined in three CD8þ T subsets, i.e. CD952CD28þ (na ̈ıve), CD95þCD282 (effector/cytotoxic), and CD95þCD28þ (memory). As a general trend, we observed, in aged subjects, an increase of type 1 and type 2 intracellular cytokines within the three CD8þ subsets. In particular, we showed that type 1 cytokine-positive cells significantly increased, with age, among all the CD8þ subsets, while a marked increase of type 2 producing cells was observed only in memory CD8þ T cells. These profound changes are compatible with inflame-aging, an hypothesis which suggest that immunosenescence is mainly driven by a chronic antigenic load which not only induces an enormous expansion of CD282 T cells, but also increases their functional activity, exemplified by an high frequency of cells positive for pro-inflammatory cytokines

Different contribution of EBV and CMV infections in very long-term carriers to age-related alterations of CD8+ T cells

Abstract Aging is accompanied by a complex dynamics of CD8þ T cell subsets whose origin is unclear. To evaluate the impact of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) chronic infections on CD8þ T cells in far advanced age, we studied CD8þ T cells frequencies and phenotype in nonagenarians and centenarians by HLA-A*0201- and HLA-B*0702-tetramers incorporating epitopes specific of both viruses along with viral replication. The results demonstrate that EBV and CMV infections induce quantitatively and qualitatively different CD8þ Tcell responses in advanced aging. The frequency and absolute number of CD8þ T cells specific for one lytic and two latent EBV-epitopes, were relatively low and mostly included within CD8þ CD28þ cells. By contrast, CMV infection was characterized by highly variable numbers of CD8þ T cells specific for two differently restricted CMV-epitopes that, in some subjects, were strikingly expanded. Moreover, the great majority of anti-CMV CD8þ T cells did not bear CD28 antigen. Notwithstanding the expansion of CMV-specific CD8þ lymphocytes, CMV-DNA detection in blood samples was invariably negative. Altogether, we suggest that CMV, but not EBV, can sustain chronic activation of the HLA-class I restricted effector arm in elderly that might have detrimental effects on age-associated diseases

Different contribution of EBV and CMV infections in very long-term carriers to age-related alterations of CD8+ T cells

Abstract Aging is accompanied by a complex dynamics of CD8þ T cell subsets whose origin is unclear. To evaluate the impact of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) chronic infections on CD8þ T cells in far advanced age, we studied CD8þ T cells frequencies and phenotype in nonagenarians and centenarians by HLA-A*0201- and HLA-B*0702-tetramers incorporating epitopes specific of both viruses along with viral replication. The results demonstrate that EBV and CMV infections induce quantitatively and qualitatively different CD8þ Tcell responses in advanced aging. The frequency and absolute number of CD8þ T cells specific for one lytic and two latent EBV-epitopes, were relatively low and mostly included within CD8þ CD28þ cells. By contrast, CMV infection was characterized by highly variable numbers of CD8þ T cells specific for two differently restricted CMV-epitopes that, in some subjects, were strikingly expanded. Moreover, the great majority of anti-CMV CD8þ T cells did not bear CD28 antigen. Notwithstanding the expansion of CMV-specific CD8þ lymphocytes, CMV-DNA detection in blood samples was invariably negative. Altogether, we suggest that CMV, but not EBV, can sustain chronic activation of the HLA-class I restricted effector arm in elderly that might have detrimental effects on age-associated diseases

Safety and efficacy of rituximab plus bendamustine in relapsed or refractory diffuse large B-cell lymphoma patients: an Italian retrospective multicenter study

Abstract: Relapsed or refractory diffuse large B-cell lymphoma (DLBCL) not suitable for high dose chemotherapy with autologous stem cell transplantation (ASCT) has a dismal prognosis and no standard therapy. We designed an Italian multicenter retrospective study aimed at evaluating the safety and efficacy of rituximab plus bendamustine (R\u2013B) as salvage treatment in patients not eligible for ASCT because of age and/or comorbidity or in patients with post-ASCT recurrence. Fifty-five patients with a median age of 76 years were included. The overall response rate was 50%, including 28% complete remission and 22% partial remission. The median overall survival (OS) was 10.8 months. The median progression free survival (PFS) was 8.8 months. Eleven patients are still alive and in complete remission at last follow-up (12\u201371 months). Toxicity was moderate, mainly grades 1 and 2. R\u2013B showed promising efficacy results with an acceptable toxicity profile and should be further investigated, possibly in combination with novel drugs