ΠPOTEYΣ

In this issue, Proteus examines the merits and dismerits of an uncommonly voiced debate: the retention of the foreskin in preventing transmission of infectious diseases, as well as progress in Neisseria meningitidis research which is developing energy akin to the disease process itself.     

Synergistic effects of interferon γ and tumour necrosis factor α on T84 cell function

BACKGROUND: Inflammatory bowel disease (IBD) is characterised by chronic intestinal inflammation and increased epithelial permeability. Both tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) have been implicated in IBD. AIMS: To understand better the effects of these cytokines on epithelial cell function. METHODS: T84 cells were cultured with IFN-gamma and TNF-alpha and changes in transepithelial resistance (TER), fluorescein isothiocyanate (FITC) dextran flux, short circuit current (I(sc)), cystic fibrosis transmembrane conductance regulator (CFTR) protein levels, cell morphology, TNF receptor gene expression, and apoptosis were assayed. RESULTS: Relative to controls, significant changes (p<0.05) occurred in cells incubated with IFN-gamma for two days: TER was decreased to 20 (6.2)%, FITC-dextran flux was increased by 109 (19)-fold, cAMP and Ca dependent I(sc) were decreased to 51 (6.4)% and 24 (2.2)%, respectively, and CFTR levels were decreased to 47 (11)%. Cell morphology was altered but cell death was not induced. TNF receptor mRNA levels were increased. When added with IFN-gamma, TNF-alpha accelerated IFN-gamma dependent changes. Relative to controls, significant changes occurred after one day of culture with IFN-gamma plus TNF-alpha: TER was decreased to 27 (3.5)%, FITC-dextran flux was increased by 185 (45)-fold, and cAMP and Ca dependent I(sc) were decreased to 66 (12)% and 35 (6.8)%, respectively. TNF-alpha also enhanced IFN-gamma dependent changes in cell morphology but did not induce cell death. CONCLUSION: IFN-gamma alters T84 cell epithelial properties and TNF-alpha can enhance these effects, perhaps due to IFN-gamma dependent increases in TNF receptor gene expression. Overall, these studies suggest that in IBD, TNF-alpha may have synergistic effects on IFN-gamma mediated alterations of epithelial cell function.     

A new β0‐thalassemia frameshift mutation [β 48 (‐T)] in a Uruguayan family

We describe here a new frameshift mutation of β‐thalassemia in a Uruguayan family with Italian ancestry [β48 (‐T); HBB:c.146delT]. This frameshift results in formation of premature stop codon (TGA) 40 bp downstream and in a short unstable product that is degraded in the cell.     

The immune suppressive effect of dexamethasone in rheumatoid arthritis is accompanied by upregulation of interleukin 10 and by differential changes in interferon γ and interleukin 4 production

OBJECTIVES: The influence of dexamethasone on interleukin 10 (IL10) production and the type 1 (T1)/type 2 (T2) T cell balance found in rheumatoid arthritis (RA) was studied. METHODS: Peripheral blood mononuclear cells (PB MNC) were isolated from 14 RA patients both before and 7 and 42 days after high dose dexamethasone pulse therapy. The ex vivo production of IL10, interferon gamma (IFN gamma) (T1 cell), and IL4 (T2 cell) by PB MNCs was assessed, along with parameters of disease activity (erythrocyte sedimentation rate, C reactive protein, Visual Analogue Scale, Thompson joint score). In addition, the in vitro effect of dexamethasone (0.02, 0.2, and 2 microM) on PB MNC IL10, IFN gamma, and IL4 production was studied. RESULTS: Dexamethasone pulse therapy resulted in a rapid and sustained decrease in RA disease activity. IL10 production increased after dexamethasone treatment and this was sustained for at least six weeks. A transient strong decrease in IFN gamma was seen shortly after corticosteroid treatment, while IL4 only decreased slightly. This led to an increased IL-4/IFN gamma ratio. In vitro, IL10 production was not detectable, IFN gamma and IL4 decreased, but the effect was more pronounced for IFN gamma than for IL4, which again resulted in an increased IL4/IFN gamma ratio. CONCLUSION: Dexamethasone therapy in RA patients leads to a rapid, clinically beneficial effect. The upregulation of IL10 production may be involved in the prolonged clinical benefit. The strong immunosuppressive effect is most evident in the decrease in IFN gamma, and is therefore accompanied by a relative shift towards T2 cell activity. In vitro evaluation showed that this shift in T cell balance was a direct effect of dexamethasone and thus independent of the hypothalamic-pituitary-adrenal axis.