Abnormal production of tumor necrosis factor (TNF) -- alpha and clinical efficacy of the TNF inhibitor etanercept in a patient with PAPA syndrome [corrected

We report a family with pyogenic sterile arthritis, pyoderna and acne syndrome (PAPA). The proband presented several episodes of sterile pyogenic arthritis and became unresponsive to glucocorticoids. After treatment with the tumor necrosis factor inhibitor etanercept, the disease underwent rapid and sustained clinical remission. Production of tumor necrosis factor-alpha by mononuclear cells of the proband and of the affected relatives was abnormally elevated.     

In vitro and ex vivo evidence for modulation of P-glycoprotein activity by progestins

The well known gender-related differences in drug action may partly be explained by changes in activity and expression of drug metabolising enzymes, but also by modulation of active drug transport systems (e.g. P-glycoprotein, Pgp) by sexual steroids, which is yet not well investigated. Because many women are using hormones (e.g. as oral contraceptives) we investigated the influence of different synthetic progestins on Pgp activity. Pgp inhibition of progesterone, medroxyprogesterone, chlormadinone, cyproterone, levonorgestrel, norethisterone, desogestrel, and norgestimate was measured in vitro in two Pgp over-expressing cell lines (L-MDR1, P388/dx cells) and the corresponding parental cell lines by means of calcein assay, and ex vivo in human peripheral blood mononuclear cells (PBMCs) by rhodamine123 efflux. For most progestins tested, concentrations needed to double baseline fluorescence (f2) in L-MDR1 cells were similar to that of the potent Pgp inhibitor quinidine, whereas levonorgestrel and norethisterone did not reach f2. The results in P388/dx cells essentially confirmed our findings in L-MDR1 cells. Additionally, Pgp inhibitory activity of all progestins tested was also shown ex vivo in PBMCs. The potent Pgp inhibition by several synthetic progestins in vitro and ex vivo suggests that such an interaction might be clinically relevant despite generally low plasma concentrations of progestins. The results may be of particular importance for Pgp substrates, such as protease inhibitors and chemotherapeutic agents, for which intracellular concentrations are critical.     

Role of leptin as an immunomodulator of blood mononuclear cells: mechanisms of action

Leptin is a an adipocyte-secreted hormone that regulates weight centrally. However, the leptin receptor is expressed not only in the central nervous system, but also in peripheral tissues, such as haematopoietic and immune systems. Therefore, the physiological role of leptin should not be limited to the regulation of food intake and energy expenditure. Moreover, the leptin receptor bears homology to members of the class I cytokine family, and recent data have demonstrated that leptin is able to modulate the immune response. Thus, the leptin receptor is expressed in human peripheral blood mononuclear cells, mediating the leptin effect on proliferation and activation. In vitro activation and HIV infection in vivo induce the expression of the long isoform of the leptin receptor in mononuclear cells. Also, leptin stimulates the production of proinflammatory cytokines from cultured monocytes and enhances the production of Th1 type cytokines from stimulated lymphocytes. Moreover, leptin has a trophic effect on monocytes, preventing apoptosis induced by serum deprivation. Leptin stimulation activates JAK-STAT, IRS-1-PI3K and MAPK signalling pathways. Leptin also stimulates Tyr-phosphorylation of the RNA-binding protein Sam68 mediating the dissociation from RNA. In this way, leptin signalling could modulate RNA metabolism. These signal transduction pathways provide possible mechanisms whereby leptin may modulate activation of peripheral blood mononuclear cells. Therefore, these data support the hypothesis regarding leptin as a proinflammatory cytokine with a possible role as a link between the nutritional status and the immune response. Moreover, these immunoregulatory functions of leptin could have some relevance in the pathophysiology of obesity.     

In vitro susceptibility of CD4+ and CD8+ T cell subsets to fludarabine

Administration of the adenosine analogue fludarabine (FLU) in vivo induces a profound and prolonged T lymphopenia which mainly affects CD4(+) cells. To better understand the mechanistic basis underlying this preferential depletion, we analyzed the in vitro susceptibility of T cell subsets to FLU-induced apoptosis. Contrasting with observations in vivo, our results showed that treatment of peripheral blood mononuclear cells with FLU induced a higher level of apoptosis in CD8(+) than in CD4(+) T lymphocytes. This increased sensitivity of CD8(+) T cells to FLU was observed in samples from both, healthy donors and B cell chronic lymphocytic leukemia patients, and resulted in higher CD4:CD8 ratios in FLU-treated than in untreated cultures (P<0.01). Expression of factors involved in FLU transport and metabolism was then evaluated by quantitative real time-PCR in normal T cell subsets. It was found that mRNA levels of human equilibrative nucleoside transporter-1 nucleoside transporter were higher whereas deoxycytidine kinase and IMP/GMP selective 5'-nucleotidase mRNA levels were lower in CD4(+) cells. However the dCK/cN-II ratio was 2-fold greater in CD8(+) than in CD4(+) T lymphocytes, which could account for the higher apoptosis levels observed in the CD8(+) subset. These results favor the view that decreased CD4:CD8 ratios in FLU-treated patients should be attributed to differences in cell recovery and/or homing between T cell subsets.     

Aldosteronism revisited: perspectives on less well-recognized actions of aldosterone

Aldosterone is a mineralocorticoid with protean actions in both epithelial and nonepithelial cells. These include endocrine properties of circulating aldosterone that promote Na(+) resorption at the expense of well-recognized K(+) excretion and less well-recognized Mg(2+) excretion in classic target tissues: kidneys, colon, and sweat and salivary glands. The regulation of adrenal aldosterone secretion by [Mg(2+)](o) is also less well appreciated. More recently recognized endocrine actions of aldosterone include induction of Mg(2+) efflux in exchange for Na(+) in such nonepithelial cells as peripheral-blood mononuclear cells and influence on epithelial cells of the choroid plexus, where aldosterone alters the composition of cerebrospinal fluid that contributes to blood-pressure regulation. An association between primary aldosteronism and idiopathic intracranial hypertension has recently been reported. Extraadrenal steroidogenesis with de novo aldosterone production by the cardiovasculature, where its auto-/paracrine properties may contribute to tissue repair at sites of injury, has been observed. These less well-recognized actions of aldosterone have led to a revival of interest in how this steroid molecule contributes to the pathophysiology of various clinical disorders.     

鲨鱼肝提取肽诱导PBMC表达mIL-2R及CD25分子

探讨能有效促进成纤维细胞等多种组织细胞增殖分化的鲨鱼肝提取肽对人外周血单个核细胞（ＰＢＭＣ）表达ＩＬ－２、ｍＩＬ－２Ｒ及ＣＤ２５分子的影响。方法：将ＰＢＭＣ细胞悬液与鲨鱼肝提取肽共同孵育诱导后,分别采用放射免疫测定法、生物素－链霉亲和素（ＢＳＡ）免疫细胞化学法与流式细胞术检测ＩＬ－２的分泌及表达ｍＩＬ－２Ｒ与ＣＤ２５分子的淋巴细胞。结果：与鲨鱼肝提取肽共同孵育的ＰＢＭＣ,表达ｍＩＬ－２Ｒ的淋巴细胞数目比对照组增高１倍以上（Ｐ＜０．００５）,最适培养终浓度为５０ μｇ／ｍｌ;淋巴细胞表面ＣＤ２５分子表达也明显增加（Ｐ＜０．０５）;但不影响ＩＬ－２的分泌。结论：鲨鱼肝提取肽对改善机体的细胞免疫功能及免疫调节机制有一定的影响。     

A shift in the Th(1)/Th(2) ratio accompanies the clinical remission of systemic lupus erythematosus in patients with end-stage renal disease.

BACKGROUND: Patients suffering from systemic lupus erythematosus (SLE) with renal involvement often show remission of systemic clinical activity after progression to end-stage renal disease (ESRD). SLE is characterized by predominantly humoral, T-helper (Th)(2)-mediated autoimmune responses. Since ESRD induces a state of immunodeficiency that affects the balance of Th cell subsets, we hypothesized that a Th(1) shift induced by ESRD leads to clinical remission of SLE. METHODS: Using single-cell measurement of intracellular cytokines by flow cytometry after polyclonal stimulation with PMA/ionomycin, helper cell profiles were analysed in SLE patients with preserved renal function and in SLE patients with ESRD, from both isolated peripheral blood mononuclear cells (PBMC) and whole blood. RESULTS: Using the whole-blood assay, patients with SLE and preserved renal function showed a predominance of Th(2) cells compared to healthy controls (patients, Th(1)/Th(2) ratio 6.0+/-1.0 vs controls, 9.0+/-1.0; P<0.05). In contrast, SLE patients with ESRD have significantly more Th(1) cells (36.8+/-5.0%) than those without ESRD (23.4+/-3.6%; P<0.05). This results in an enhancement of the Th(1)/Th(2) ratio to 12.1+/-2.6, which is not significantly different from healthy controls. These data were confirmed using a PBMC-based assay. CONCLUSIONS: SLE patients with preserved renal function show a bias in the differentiation of Th cells towards Th(2). Once ESRD occurs, the Th(1)/Th(2) ratio normalizes. This may contribute to the remission of Th(2)-mediated autoimmune diseases such as SLE.