Correlation between intracellular interferon-gamma (IFN-gamma) production by CD4+ and CD8+ lymphocytes and IFN-gamma gene polymorphism in patients with type 2 diabetes mellitus and latent autoimmune diabetes of adults (LADA)

IFN-gamma is considered to be involved in the pathogenesis of diabetes mellitus. In this study, the presence of T/A mutation at position -874 in IFN-gamma gene was assessed in patients with latent autoimmune diabetes of adults (LADA), in patients with type 2 diabetes and in healthy individuals. Subsequently, an attempt was made to correlate the presence of this mutation with the ability of CD4+ or CD8+ lymphocytes from these individuals to release IFN-gamma following mitogenic stimulation. There were no significant differences in the distribution of genotypes and haplotypes in the three study groups. However, the frequency of the low IFN-gamma production allele (IFN-gamma 874( *)A) was significantly higher in type 2 diabetics compared to controls. CD4+ and CD8+ cells obtained from type 2 diabetics released significantly lower amounts of IFN-gamma in the intracellular space, compared to those released by cells obtained from LADA patients and healthy volunteers. Furthermore, even CD4+ and CD8+ from type 2 diabetics bearing the TT genotype (high producers) released significantly lower amounts of IFN-gamma than LADA patients carrying the same genotype, probably due to the activity of molecules directly or indirectly inhibiting IFN-gamma production. The results of this study indicate that IFN-gamma may contribute to the development of type 2 diabetes, based on a combination of molecular and immunological observations.

TNF-alpha, TGF-beta1, IL-10, IL-6, gene polymorphisms in latent autoimmune diabetes of adults (LADA) and type 2 diabetes mellitus

Abundant evidence suggests that cytokines involve in the pathogenesis of latent autoimmune diabetes of adults (LADA). This is a slowly progressive form of type 1 diabetes, which is initially diagnosed as type 2 diabetes. In this study, healthy individuals LADA and type 2 diabetic patients were genotyped for IL-6-174G/C, TNF-alpha-308A/G, TGF-beta1-codon10T/C, TGF-beta1-codon25G/C, IL-10-1082A/G, IL-10-819T/C, IL-10-592A/C gene polymorphisms, by sequence-specific-primer polymerase chain reaction methodology. A significant difference in the frequencies of -1082A/G IL-10 alleles was observed, with the -1082*A allele (known to be associated with low IL-10 production), predominating in LADA diabetics than type 2 diabetics (p=0.036). No significant differences of genotypes, phenotypes, or haplotype frequencies in the remaining cytokine polymorphisms were observed. Analysis of allele combinations revealed a significant involvement of the low and high in vitro production IL-10 alleles in the development of LADA and type 2 diabetes, respectively. These results suggest that the G/A mutation at position -1082 of IL-10 promoter gene region might be one of the factors participating to the pathogenesis of LADA diabetes and that identification of cytokine gene polymorphisms might contribute to the characterization of the different types of diabetes mellitus.

Intracellular IFN-gamma production and IL-12 serum levels in latent autoimmune diabetes of adults (LADA) and in type 2 diabetes

Th1 cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), and Th1-inducing cytokines, such as IL-12, are involved in the pathogenesis of various organ-specific autoimmune diseases, including autoimmune diabetes. In this study, we investigated intracellular IFN-gamma release by T lymphocytes and IL-12 serum levels in 48 type 2 and 36 latent autoimmune diabetes of adults (LADA) diabetics and 25 control subjects in an attempt to evaluate their role in the pathogenesis of these clinical entities. Ionomycin (ION) and phorbol-12-myristate-13-acetate (PMA)-activated peripheral blood mononuclear cells (PBMCs) were stained with anti-CD4-FITC or anti-CD8-FITC and anti-IFN-gamma phycoerythrin (PE) monoclonal antibodies (mAbs) and analyzed by flow cytometry. IL-12 serum levels were determined by enzyme-linked immunosorbent assay (ELISA). In all study groups, IFN-gamma content of CD4(+) and CD8(+) lymphocytes was significantly upregulated by stimulation. Furthermore, it was observed that CD4(+) and CD8(+) lymphocytes from type 2 diabetics produced significantly lower levels of IFN-gamma compared with LADA patients and controls. However, the percentages of CD4(+)/IFN-gamma(+) and CD8(+)/IFN-gamma(+) cells from type 2 diabetics were significantly higher compared with controls. The flow cytometric picture of intracellular IFN-gamma release in LADA patients did not differ from that observed in controls. However, IL-12 serum levels in type 2 and LADA diabetics were lower than in controls. Because Th1 cytokines have been associated with the pathogenesis of autoimmune diabetes, these results preclude Th1 involvement in the autoimmune phenomena observed in LADA patients. In contrast, the low IFN-gamma levels observed in type 2 diabetics in combination with the low IL-12 serum levels might be a contributing factor in the frequently observed chronic complications in these patients.

Peripheral sensory neuropathy associated with short-term oral acitretin therapy

A 57-year-old female patient with widespread chronic plaque psoriasis and a 32-year-old male patient with severe oral lichen planus are reported, who developed sensory symptoms in the extremities 3 and 4 months after the onset of oral acitretin therapy, respectively. Both patients showed clinical and electrophysiological evidence of a sensory peripheral neuropathy, which completely resolved 2 and 2.5 years after discontinuation of oral acitretin administration, respectively.

Flow cytometric detection of intracellular IL-12 release: in vitro effect of widely used immunosuppressants

Interleukin 12 (IL-12) is a potent regulator of the Th1/Th2 pathway, enhancing alloantigen-specific immune functions. In the present study, we developed a flow cytometric assay detecting intracellular IL-12 production by human CD14+ monocytes in order to assess the in vitro effects of widely used immunosuppressants, such as cyclosporine (CsA), sirolimus (SRL) and dexamethasone (DXM). For the purpose of the study, a two-step activation procedure was developed involving the preactivation of peripheral blood mononuclear cells (PBMC) with interferon-gamma (IFN-gamma) and reactivation with IFN-gamma and lipopolysaccharide (LPS). All immunosuppressive agents were added at the initiation of the preactivation or the reactivation step. Following this activation protocol, a fourfold to fivefold up-regulation of the percentage of CD14+/IL-12+ cells and of the mean fluorescence intensity was observed. CsA did not significantly affect the intracellular IL-12 release by CD14+ cells, independent of the time point of the addition. SRL exerted an up-regulatory effect when added at the initiation of the IFN-gamma pre-incubation, and this was manifested as a significant increase in the percentage of CD14+/IL-12+ cells. In contrast, DXM effectively repressed both the percentage and the fluorescence intensity of IL-12-producing CD14+ cells when added at the initiation of the reactivation step. Since only the steroid preparation was shown to down-regulate the intracellular release of IL-12, it is tempting to assume that steroid addition in immunosuppressive schemes is beneficial for the suppression of Th1-inducing cytokine production, as well as for the compensation of possible up-regulation induced by other immunosuppressive agents administered concurrently.

Physical training reduces peripheral markers of inflammation in patients with chronic heart failure

AIMS

Previous studies have shown an abnormal expression of cellular adhesion molecules and cytokines in chronic heart failure, which may be related to endothelial dysfunction characterizing this syndrome. Our study investigates the effects of physical training on serum activity of some peripheral inflammatory markers associated with endothelial dysfunction, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage chemoattractant protein-1 (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) in patients with chronic heart failure.

METHODS AND RESULTS

Serum levels of GM-CSF, MCP-1, sICAM-1 and sVCAM-1 were determined in 12 patients with stable chronic heart failure (ischaemic heart failure: 6/12, dilated cardiomyopathy: 6/12, New York Heart Association: II-III, ejection fraction: 24+/-2%) before and after a 12-week programme of physical training in a randomized crossover design. In addition, the functional status of chronic heart failure patients was evaluated by using a cardiorespiratory exercise stress test to measure peak oxygen consumption. Physical training produced a significant reduction in serum GM-CSF (28+/-2 vs 21+/-2 pg. ml(-1), P<0.001), MCP-1 (192+/-5 vs 174+/-6 pg. ml(-1), P<0.001), sICAM-1 (367+/-31 vs 314+/-29 ng. ml(-1), P<0.01) and sVCAM-1 (1247+/-103 vs 1095+/-100 ng. ml(-1), P<0.01) as well as a significant increase in peak oxygen consumption (14.6+/-0.5 vs 16.5+/-0.5 ml. kg(-1)min(-1), P<0.005). A significant correlation was found between the training-induced improvement in peak oxygen consumption and percentage reduction in soluble adhesion molecules sICAM-1 (r=-0.72, P<0.01) and sVCAM-1 (r=-0.67, P<0.02).

CONCLUSION

Physical training affects beneficially peripheral inflammatory markers reflecting monocyte/macrophage-endothelial cell interaction. Training-induced improvement in exercise tolerance is correlated with the attenuation of the inflammatory process, indicating that inflammation may contribute significantly to the impaired exercise capacity seen in chronic heart failure.

Cell adhesion molecules in relation to simvastatin and hormone replacement therapy in coronary artery disease

AIMS

To assess the effect of simvastatin, hormone replacement therapy and their combination on soluble cell adhesion molecules and plasma lipids, in hypercholesterolaemic post-menopausal women with coronary artery disease.

METHODS

We studied 16 post-menopausal women with coronary artery disease and hypercholesterolaemia (total cholesterol >200mg x dl(-1) and LDL cholesterol >130 mg x dl(-1)). We compared simvastatin (20 mg daily) with hormone replacement therapy (0.625 mg conjugated oestrogen and 2.5 mg medroxyprogesterone acetate daily) and their combination, in a randomized, crossover, placebo controlled study. Each treatment period was 8 weeks long with a 4 week washout interval between treatments. Circulating cell adhesion molecules and plasma lipids were evaluated at the end of each treatment period.

RESULTS

All three active treatments--simvastatin, hormone replacement therapy and the combination therapy--significantly reduced total and LDL cholesterol, compared to placebo (P<0.001). Only hormone replacement therapy, alone and in combination with simvastatin, significantly decreased lipoprotein(a) when compared to placebo (P<0.05), whereas simvastatin had no significant effect. Likewise, hormone replacement therapy and the combination therapy significantly reduced the intercellular adhesion molecule (ICAM-1) plasma levels (P=0.03 and P=0.02, respectively), while simvastatin, which was superior to hormone replacement therapy in lowering total and LDL cholesterol, did not modify ICAM-1 levels; the combination therapy was not more effective than hormone replacement therapy alone in ICAM-1 reduction. Neither the effect, on any treatment when compared to placebo, of VCAM-1 nor E-selectin levels differed significantly.

CONCLUSIONS

Hormone replacement therapy may limit the inflammatory response to injury by modulating the expression of cell adhesion molecules from the endothelial cells, possibly in association with lipoprotein (a) reduction.

Polymorphism and distribution of HLA-DR2 alleles and haplotypes in a Greek population

HLA-DR2 serological subtyping has indicated that the DR16 serotype appears at a higher frequency relative to the DR15 serotype in the Greek population, differing from the distribution observed in most other Caucasian groups. In this study, we have analyzed by the PCR-SSP technique a DR2-positive group of unrelated Greek individuals selected from our normal control panel for the different DRB1, DRB5, DQB1 and DQA1 DR2-associated alleles present. Six of the 50 individuals analyzed were homozygous for DR2, contributing a total of 56 haplotypes for DR2. The observed frequencies of the DR2-related DRB1 alleles were as follows: 58.9% for the DRB1*1601, 7.1% for the DRB1*1602, 25.0% for the DRB1*1501 and 7.1 % for the DRB1*1502 allele. The rare allele DRB1*1605 was detected in one heterozygous sample and its presence was definitively established by DNA sequencing. The alleles *1503, *1504, *1505, *1603 and *1604 were not detected. Three DRB5 alleles were identified: DRB5*0202 (67.8%), DRB5*0101 (25.0%) and DRB5*0102 (7.1%). Ten different DRB1/DQB1/ DQA1 DR2-associated haplotypes were defined. The most frequently observed haplotype was DRB1*1601-DQB1*0502-DQA1*0102 (relative frequency=57%) followed by DRB1*1501-DQB1*0602-DQA1*0102 (relative frequency=14.3%). In conclusion, the refined analysis of the DR2-associated DRB1 alleles in the Greek population revealed the prevalence of the DRB1*1601 allele. The rare allele DRB1*1605 was demonstrated once. A considerable variety of different DR2-related DR/DQ haplotypes was detected and the overall haplotypic frequencies in the Greek population are distributed differently compared to those reported for most other Caucasian populations.

In vitro effects of retinoids on mitogen-induced peripheral blood leucocyte responses

The aim of the present study was to investigate the influence of three different retinoids, isotretinoin, etretinate and acitretin, on the mitogenic response of peripheral blood mononuclear cells (PBMCs) to PHA and PMA in vitro. All three retinoids at high concentrations (10(-4)M) significantly inhibited the mitogenic response of PBMCs to these mitogens. At lower concentrations (10(-5) M and 10(-6) M) none of the three retinoids had any effect on PBMC proliferation in response to PHA. Interestingly, isotretinoin and etretinate significantly enhanced the PMA-induced stimulation of proliferation, whereas acitretin at 10(-5) M failed to influence the mitogenic response to PMA but enhanced it at 10(-6) M. The enhancing effects of retinoids on the proliferative response of PMA-stimulated PBMCs were reversed by rapamycin (10 ng/ml), an immunosuppressant known to inhibit the phorbol ester-induced protein kinase C pathway of lymphocyte activation. In conclusion, our study indicates that retinoids directly trigger the PMA-induced protein kinase C pathway of lymphocyte activation in a concentration-dependent manner. This observation could explain the findings of previous studies showing an in vivo immunopotentiating effect of retinoids on certain immune functions.