Lymphocyte subset patterns and cytokine production in Alzheimer's disease patients.

To investigate the signs of inflammatory processes in Alzheimer's disease (AD), we examined peripheral blood mononuclear cells (PBMC) from 51 AD patients (29 with mild and 22 with moderately severe dementia) and 51 age-matched healthy controls (HC), using flow cytometry to analyse the absolute number and the percentage of T, B and NK cells. We also studied the surface expression of CD25, CD28, CD57, CD71, CD45RA and CD45RO markers on cells CD4+ and CD8+. In 30 AD patients and 20 HC the production of IL-2, IFN-gamma, IL-10 and TNF-alpha by PBMC after stimulation with [25-35], [1-40] and [1-16] beta-amyloid (betaA) fragments was also evaluated. A significant decrease in circulating B and CD8+CD28- cells, as well as an increase in CD8+ cells expressing CD71+ and CD28+, was observed in AD patients. A significant decrease in IL-10 production was also found after stimulation of PMBC with betaA [1-40]. The decreased IL-10 production was not related to disease severity. The observed imbalance of immune peripheral cell subpopulations and decreased IL-10 production point to a reduction of suppressor cell function in AD patients.

Big endothelin-1 and interleukin-6 modulation in human microvascular endothelial cells after human herpesvirus 8 infection.

Endothelin (ET)-1 is an angiogenic factor that, among others, is secreted by endothelial cells during development of several neoplasias. In particular, Kaposi sarcoma (KS) skin lesions show overexpression of the ET-1 system. Spindle cells, which characterize tumor lesions, are of endothelial origin and during disease are infected by human herpesvirus 8 (HHV-8). The majority of these cells are latently infected, suggesting that latent genes are sufficient for maintenance of viral infection and development of KS. The establishment of a reliable infection system is required to better understand the role of viral and cellular angiogenic factors involved in KS progression. For this purpose, we used human microvascular endothelial cells (HMEC-1) to establish an ET-1-producing model of infection with HHV-8. Viral particles purified from BCBL-1 cells were used to infect HMEC-1 monolayer, and infection was assessed by polymerase chain reaction, reverse transcription polymerase chain reaction, and confocal microscopy. Mitochondrial activity and cell viability, measured at 24, 48, and 72 hours after infection by 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, was reduced in HHV-8-infected cells compared with control. In contrast, 1 week after infection, HHV-8-positive cells showed higher mitochondrial functionality. Endothelin production was measured in culture media collected at 24, 48, and 72 hours after infection. The levels of endothelin precursor big endothelin-1 was increased 3 days after infection, although big ET-1 and ET-1 production did not differ significantly between infected and uninfected cells. These results indicate this model as a useful tool to further characterize the effects of HHV-8 in the early and late phases of infection, and to determine its ability to interfere with the endothelin system.

Programmed cell death of myelin basic protein-specific T lymphocytes is reduced in patients with acute multiple sclerosis.

We investigated the apoptosis of myelin basic protein (MBP)-specific T lymphocytes in multiple sclerosis (MS) patients with acute (AMS) or stable (SMS) MS by evaluating the expression of apoptosis markers on peripheral cells. Cells of healthy controls (HC) were evaluated as well. Results showed that mitogen-stimulated apoptosis was comparable among patients and controls, whereas MBP-stimulated CD4+ and CD8+ 7-AAD+ and 7-AAD+ Fas+ cell (apoptotic cells) were significantly reduced in AMS patients. A reduction of the apoptotic rate of myelin-specific CD4+ and CD8+ T lymphocytes could be involved in the immune-mediated destruction of the myelin sheath seen in AMS patients.

1-40 Beta-amyloid protein fragment modulates the expression of CD44 and CD71 on the astrocytoma cell line in the presence of IL1beta and TNFalpha.

The modulation of CD44, VCAM-1 and CD71 expression was analysed by flow cytometry in the 1321N1 astrocytoma cell line in the presence of interleukin-1beta (IL1beta), tumour necrosis factor-alpha (TNFalpha) and 1-40 or 25-35 beta-amyloid (Abeta) fragments. The percentage of 1321N1 astrocytoma cell line expressing these markers increased significantly after treatment with TNFalpha or IL1beta. The presence of Abeta 1-40 fragment, alone or in combination with IL1beta, induced an increase in the percentage of cells expressing CD44, but not VCAM-1. However, the concomitant presence of Abeta 1-40 fragment and of IL1beta or TNFalpha caused an increase in the percentage of CD71 positive cells. In contrast, the shorter Abeta 25-35 fragment was always inactive. These results indicates that Abeta 1-40 fragment, in association with cytokines, can activate this astrocyte-derived cell line and add further elements in favour of the hypothesis that beta-amyloid can act as immunological mediator.

Endothelin-1 production by a microvascular endothelial cell line treated with Plasmodium falciparum parasitized red blood cells.

In this study, we investigated the production of endothelin 1 (ET-1) by a human microvascular endothelial cell line, HMEC-1, co-cultured with Plasmodium falciparum-parasitized red blood cells (pRBCs). The results indicate that hypoxia increased the basal level of ET-1 production by HMEC-1 cells after 24 or 48 h of treatment. However, the co-incubation of HMEC-1 cells with pRBCs, but not with uninfected RBCs, induced a dose-dependent decrease of both constitutive and hypoxia-induced ET-1 production. The inhibition was not due to a decrease in cell viability, as lactate dehydrogenase release remained constant. These results indicate that pRBCs are able to interfere with both the constitutive and stimulated ET-1 release from the microvascular endothelium, thus inducing local modifications of the vascular tone and of the inflammatory response. This could be of relevance in the pathogenesis of the most severe forms of P. falciparum infections, such as cerebral malaria or malaria during pregnancy.