Potential involvement of Fas and its ligand in the pathogenesis of Hashimoto's thyroiditis

The mechanisms responsible for thyrocyte destruction in Hashimoto's thyroiditis (HT) are poorly understood. Thyrocytes from HT glands, but not from nonautoimmune thyroids, expressed Fas. Interleukin-1beta (IL-1beta), abundantly produced in HT glands, induced Fas expression in normal thyrocytes, and cross-linking of Fas resulted in massive thyrocyte apoptosis. The ligand for Fas (FasL) was shown to be constitutively expressed both in normal and HT thyrocytes and was able to kill Fas-sensitive targets. Exposure to IL-1beta induced thyrocyte apoptosis, which was prevented by antibodies that block Fas, suggesting that IL-1beta-induced Fas expression serves as a limiting factor for thyrocyte destruction. Thus, Fas-FasL interactions among HT thyrocytes may contribute to clinical hypothyroidism.

Nitric oxide primes pancreatic beta cells for Fas-mediated destruction in insulin-dependent diabetes mellitus

Fas is an apoptosis-inducing surface receptor involved in controlling tissue homeostasis and function at multiple sites. Here we show that beta cells from the pancreata of newly diagnosed insulin-dependent diabetes mellitus (IDDM) patients express Fas and show extensive apoptosis among those cells located in proximity to Fas ligand-expressing T lymphocytes infiltrating the IDDM islets. Normal human pancreatic beta cells that do not constitutively express Fas, become strongly Fas positive after interleuken (IL)-1beta exposure, and are then susceptible to Fas-mediated apoptosis. NG-monomethyl-L-arginine, an inhibitor of nitric oxide (NO) synthase, prevents IL-1beta-induced Fas expression, whereas the NO donors sodium nitroprusside and nitric oxide releasing compound (NOC)-18, induce functional Fas expression in normal pancreatic beta cells. These findings suggest that NO-mediated upregulation of Fas contributes to pancreatic beta cell damage in IDDM.

Visceral adiposity index is associated with significant fibrosis in patients with non-alcoholic fatty liver disease

BACKGROUND

Metabolic factors have been associated with liver damage in patients with non-alcoholic fatty liver disease (NAFLD).

AIMS

To test a new marker of adipose dysfunction, the visceral adiposity index (VAI), in NAFLD patients to assess whether or not it is associated with host factors, and to investigate a potential correlation with histological findings.

METHODS

One hundred and forty-two consecutive NAFLD patients were evaluated by liver biopsy, and clinical and metabolic measurements, including insulin resistance with the homeostasis model assessment (HOMA), and VAI by using waist circumference, body mass index, triglycerides and HDL. Serum levels of TNFα, IL-6, adiponectin and leptin were also assessed. All biopsies were scored for NAFLD activity score (NAS) and its components, and for staging (Kleiner).

RESULTS

By multiple linear regression analysis, VAI was independently associated with higher HOMA (P = 0.04), and fibrosis (P = 0.04). In addition, an independent association was found between higher VAI and lower adiponectin levels (P = 0.002). Higher HOMA (OR 1.149, 95% CI 1.003-1.316, P = 0.04), higher VAI (OR 1.446, 95% CI 1.023-2.043, P = 0.03), lobular inflammation (OR 3.777, 95% CI 1.771-8.051, P = 0.001), and ballooning (OR 2.884, 95% CI 1.231-6.757, P = 0.01) were correlated with significant fibrosis (F2-F4) on multiple logistic regression analysis. In particular, the prevalence of significant fibrosis progressively increased from patients with a VAI ≤ 2.1 and HOMA ≤ 3.4 (26%) to those with a VAI > 2.1 and HOMA > 3.4 (83%).

CONCLUSIONS

In NAFLD patients, visceral adiposity index is an expression of both qualitative and quantitative adipose tissue dysfunction and, together with insulin resistance, is independently correlated with significant fibrosis.

Cytokine profiles in drug-naive schizophrenic patients

A large body of evidence concerning immunological abnormalities in schizophrenic patients seems to suggest a role of the immune system in the multifactorial pathogenesis of schizophrenia. We investigated the production of various cytokines [interleukin (IL)-2, IL-4, IL-10, interferon (INF)-gamma] in drug-free (n=26) and drug-naive (n=7) schizophrenic patients and in healthy controls (n=33). Production of IL-2 and INF-gamma was significantly higher (respectively P=0.021 and P=0.001) in patients than in controls. These findings provide further evidence that immunological abnormalities are present in some schizophrenic patients.

Patterns of brain structural changes in first-contact, antipsychotic drug-naive patients with schizophrenia

BACKGROUND AND PURPOSE

Previous studies have suggested that structural changes do occur in the brain of patients with schizophrenia compared with healthy control participants. However, findings from such studies are inconclusive, probably because of the different methodologic approaches, the clinical heterogeneity of patient samples, and also the fact that patients enrolled were treated with antipsychotic drugs. The aim of this study was to investigate brain GM volumes and intrinsic structural WM changes in first-contact, antipsychotic drug-naïve patients with schizophrenia.

MATERIALS AND METHODS

A total of 43 first-contact, drug-naïve, patients with schizophrenia and 17 age-matched control participants were studied. All participants underwent T1-weighted MR imaging and DTI scans. Voxel-based morphometry and tract-based spatial statistics were used to compare GM volumes and WM DTI metrics between groups. MR imaging measures were correlated with the duration of the untreated psychosis and the clinical positive and negative symptoms.

RESULTS

Compared with control participants, patients with schizophrenia showed smaller volumes of the temporal, parietal, and occipital GM, and a pattern of decreased mean diffusivity and increased fractional anisotropy in the brain stem and cerebellum bilaterally, interhemispheric and cortico-cortical connections bilaterally, and right anterior and posterior limb of the internal capsule. In patients, decreased mean diffusivity and increased fractional anisotropy in several brain regions were related to a longer duration of the untreated psychosis and the severity of positive symptoms.

CONCLUSIONS

First-contact, drug-naïve, patients with schizophrenia present with volumetric and DTI changes, which correlated with their clinical features. This study increases our knowledge on the neural networks involved in the pathophysiologic mechanisms of schizophrenia.

Metabolic parameters and adipokine profile during GH replacement therapy in children with GH deficiency

OBJECTIVE

GH replacement therapy in children with GH deficiency (GHD) mainly promotes linear growth. Not only have very few studies fully analyzed the metabolic consequences of GH therapy, but also the question as to whether GH may affect adipokine secretion has been insufficiently investigated. Our aim was to study the effects of GH replacement therapy on auxological data, lipid and glycemic profiles, insulin homeostasis (HOMA-IR) and serum adipokines in children.

METHODS

This was a 1-year prospective study. Thirty-four GHD children (11.6 +/- 2.6 years) and thirty healthy matched controls were enrolled. Children affected by GHD were studied both before beginning continuous GH replacement therapy and again at 12 months.

RESULTS

At the beginning of the study, total and LDL cholesterol were higher in GHD children than in controls (P<0.001), whereas HDL cholesterol, triglycerides, insulin, HOMA-IR, leptin, and adiponectin were similar. At 12 months of continuous GH replacement therapy in the GHD group, there was a significant increase in both auxological data and IGF-I (P<0.001); total cholesterol (P<0.001), LDL (P<0.001), triglycerides (P<0.005), and leptin (P<0.001) decreased significantly; HDL (P<0.003), insulin (P<0.001), HOMA-IR (P<0.001) increased while adiponectin was unmodified. Furthermore, IGF-IDelta showed an inverse correlation with leptin Delta (rho = -0.398, P = 0.02).

CONCLUSIONS

In GHD children, the evaluation of metabolic parameters proves to be a useful tool for the evaluation of auxological parameters during GH replacement therapy. In our study, GH replacement therapy in GHD children improved final height, restored IGF-I levels, reduced leptin levels, and improved the lipid profile, without producing any unfavorable effects on glucose metabolism.

Defective T cell receptor/CD3 complex signaling in human type I diabetes

The autoimmune process leading to the destruction of pancreatic beta-cells is mediated by T lymphocytes. Peripheral T cells from subjects with preclinical and clinical type I diabetes respond weakly in vitro to lectin stimulation. We, therefore, investigated in a group of newly diagnosed diabetic patients the presence of a defect in the signal transduction pathway of the T cell receptor (TcR)/CD3 complex. Following stimulation with anti-CD3-coupled beads, the proliferative response in diabetic T cells was significantly decreased in comparison with that from normal T cells. Interestingly, addition of either recombinant interleukin (IL)-2 or phorbol 12-myristate 13-acetate to the cell culture was able to completely restore impaired anti-CD3-induced proliferation in diabetic T cells, suggesting the presence of a defect through the TcR/CD3 pathway, located upstream of protein kinase C (PKC) activation and resulting in low IL-2 production and proliferation. Intracellular Ca2+ measurements by Fluo-3 labeling and flow cytometry analysis on diabetic and control T cells after anti-CD3 stimulation gave comparable results, indicating that this defect does not involve events leading to intracellular Ca2+ mobilization. In contrast, anti-CD3 stimulation of diabetic T cells resulted in a marked impairment of PKC translocation and CD69 antigen expression, as assessed by peptide substrate phosphorylation and by flow cytometry analysis, respectively. Taken together, our data clearly show the presence in individuals at the onset of the disease of an in vitro defect in the signal transduction pathway of the TcR/CD3 complex, resulting in ineffective PKC activation which is not able to induce normal IL-2 production and proliferation of diabetic T cells.

Regulation of apoptosis in endocrine autoimmunity: insights from Hashimoto's thyroiditis and Graves' disease

Dysregulation of apoptosis is associated with the pathogenesis of organ-specific autoimmune diseases, through altered target organ susceptibility. Apoptosis signaling pathways can be initiated through activation of death receptors such as Fas. A comparative analysis of the expression of Fas and FasL, the antiapoptotic molecule Bcl-2, and apoptosis in both thyrocytes and thyroid-infiltrating lymphocytes (TILs) from patients with either Graves' disease (GD) or Hashimoto's thyroiditis (HT) was performed. GD thyrocytes expressed less Fas than HT thyrocytes, whereas GD TILs had higher levels of Fas and FasL than HT TILs. GD thyrocytes expressed higher levels of Bcl-2 compared with HT thyrocytes. The opposite pattern was observed in GD (low Bcl-2) and HT (high Bcl-2) TILs. Consistently, thyrocyte apoptosis was marked in HT and poor in GD thyroids, and TIL apoptosis was marked in GD and poor in HT. Our findings suggest that in GD thyroid the regulation of Fas/FasL/Bcl-2 favors apoptosis of infiltrating lymphocytes. Moreover, the reduced levels of Fas/FasL and increased levels of Bcl-2 should favor thyrocyte survival and hypertrophy associated with stimulatory thyroid-stimulating hormone receptor antibodies. In contrast, the regulation of Fas/FasL/Bcl-2 expression in HT can promote thyrocyte apoptosis via homophylic Fas-FasL interactions, and a gradual reduction in thyrocyte numbers leading to hypothyroidism. Fas-mediated apoptosis may be a general mechanism of cell damage in destructive organ-specific autoimmunity.

Outcome of pregnancy in type 1 diabetic patients treated with insulin lispro or regular insulin: an Italian experience

Some studies have shown that fetal outcome observed in patients using insulin lispro is much the same as in pregnant women using regular insulin. This study aims to analyze the Italian data emerging from a multinational, multicenter, retrospective study on mothers with type 1 diabetes mellitus before pregnancy, comparing those treated with insulin lispro for at least 3 months before and 3 months after conception with those treated with regular insulin. The data collected on pregnant women with diabetes attending 15 Italian centers from 1998 to 2001 included: HbA1c at conception and during the first and third trimesters, frequency of severe hypoglycemic episodes, spontaneous abortions, mode and time of delivery, fetal malformations and mortality. Seventy-two diabetic pregnancies treated with lispro and 298 treated with regular insulin were analyzed, revealing a trend towards fewer hypoglycemic episodes in the former, who also had a significantly greater reduction in HbA1c during the first trimester. The rate of congenital malformations was similar in the offspring of the two groups of women treated with insulin lispro or regular insulin. These findings suggest that insulin lispro could be useful for the treatment of hyperglycemia in type 1 diabetic pregnant women.

Differential regulation of Fas-mediated apoptosis in both thyrocyte and lymphocyte cellular compartments correlates with opposite phenotypic manifestations of autoimmune thyroid disease

Several mechanisms are probably involved in determining the evolution of autoimmune thyroid disease (AITD) towards either hypothyroidism and the clinical syndrome known as Hashimoto's thyroiditis (HT) or toward hyperthyroidism and the symptoms of Graves' disease (GD). To gain further insight into such mechanisms we performed an exhaustive comparative analysis of the expression of key molecules regulating cell death (Fas, Fas ligand [FasL], Bcl-2) and apoptosis in both thyrocytes and thyroid infiltrating lymphocytes (TILs) from patients with either GD or HT. GD thyrocytes expressed less Fas/FasL than HT thyrocytes, whereas GD TILs had higher levels of Fas/FasL than HT TILs. GD thyrocytes expressed increased levels of the antiapoptotic molecule Bcl-2 compared to the low levels detected in HT thyrocytes. The opposite pattern was observed in GD (low Bcl-2) and HT (high Bcl-2) TILs. The patterns of apoptosis observed were consistent with the regulation of Fas, FasL, and Bcl-2 described above. Our findings suggest that in GD thyroid the regulation of Fas/FasL/Bcl2 favors apoptosis of infiltrating lymphocytes, possibly limiting their autoreactive potential and impairing their ability to mediate tissue damage. Moreover, the reduced levels of Fas/FasL and increased levels of Bcl-2 should favor thyrocyte survival and favor the thyrocyte hypertrophy associated with immunoglobulins stimulating the thyrotropin (TSH) receptor. In contrast, the regulation of Fas/FasL/Bcl2 expression in HT promotes thyrocyte apoptosis, tissue damage, and a gradual reduction in thyrocyte numbers leading to hypothyroidism. These findings help define key molecular mechanisms contributing to the clinical outcome of thyroid autoimmunity.

Interleukin 2 and soluble interleukin 2-receptor secretion defect in vitro in newly diagnosed type I diabetic patients

In this study, we investigated whether an interleukin 2 (IL-2) secretion defect by peripheral blood mononuclear cells (PBMCs) after in vitro stimulation with phytohemagglutinin (PHA-M) occurs in either newly diagnosed or long-standing type I (insulin-dependent) diabetic patients and whether it is accompanied by a dysregulation of soluble IL-2-receptor (IL-2RS) production. PBMC cultures (2.5 x 10(6) cells), unstimulated or stimulated with PHA-M (25 micrograms/ml), from 20 type I diabetic patients (10 with time since onset less than 3 mo and 10 with long-term diabetes of less than 3 yr) and 10 control subjects were studied for the production of IL-2 and IL-2RS in their respective supernatants. No difference was found in IL-2 production in unstimulated cultures of type I patients compared with control subjects, although a significant decrease from PHA-M-stimulated cultures were seen (newly diagnosed, 1.7 +/- 0.3 ng/2.5 x 10(6) cells; long-standing, 2.2 +/- 0.3 ng/2.5 x 10(6) cells; P less than .001 and P less than .05, respectively) compared with control subjects (3.6 +/- 0.4 ng/2.5 x 10(6) cells). In regard to the production of IL-2RS, no difference exists for unstimulated cultures, whereas, after PHA-M stimulation, both newly diagnosed and long-term-diabetic patients showed a decrease in the IL-2RS levels (318 +/- 50 and 331 +/- 62 U/2.5 x 10(6) cells; P less than .02 and P less than .05, respectively) compared with normal subjects (463 +/- 34.2 U/2.5 x 10(6) cells). Thymus-activated cell phenotypes confirmed the T-lymphocyte activation after a 48-h culture period.(ABSTRACT TRUNCATED AT 250 WORDS)

Possible pathogenetic relevance of interleukin-1 beta in "destructive" organ-specific autoimmune disease (Hashimoto's thyroiditis)

Thyroid follicular cells (TFC) abundantly express a variety of immunologically relevant surface molecules in Hashimoto's thyroiditis (HT), for example, MHC antigens and adhesion molecules such as ICAM-1. Cytokines produced by infiltrating type 1 helper and cytotoxic T cells are importantly involved in de novo expression or up-regulation of such molecules. We recently demonstrated that TFC from HT patients almost invariably bear on their surface two additive functional molecules: Fas/Apo1/CD95, an important participant in apoptosis, and B7.1, a member of a family of "co-stimulatory" molecules that are crucial for efficient antigen presentation. To date, 12 out of 14 surgical HT thyroid specimens that we studied by immunohistochemistry showed B7.1-positive TFC, and all showed Fas-positive TFC, different from Graves' disease (GD) or nonautoimmune specimens. We have investigated the role of a number of cytokines (IL-1 beta, TNF-alpha, IL-4, IL-6, IL-10, IL-12, TGF-beta 1, IFN-gamma) in regulating B7.1 and Fas expression. The experiments were performed by immunofluorescence flow cytometry on TFC purified from nontoxic goiter specimens which were Fas- and B7.1-negative at baseline, and one B7.1/Fas-positive HT specimen. IFN-gamma (500 U/mL) and TNF-alpha (200 ng/mL) were unable to induce de novo expression of B7.1 or Fas on cultured TFC. At higher doses (2000 U/mL and 800 ng/mL, respectively), they were unable to induce B7.1, but potentiated the spontaneous expression of Fas. Type 2 cytokines (IL-4 and IL-10) were unable to induce Fas or B7.1 on TFC at all, or to down-regulate Fas or B7.1 when expressed. On the other hand, IL-1 beta was the only cytokine able to induce Fas expression on Fas-negative TFC at doses ranging from 100 to 1000 pg/mL. Moreover, at a dose of 400 pg/mL, it was also able to induce B7.1. We demonstrated by immunohistochemistry that IL-1 beta is abundantly present on HT thyroids, including follicular structures. It is conceivable that IFN-gamma, or other cytokines secreted by infiltrating T-lymphocytes, are able to promote IL-1 beta secretion by TFC. In conclusion, a crucial role of IL-1 beta in "destructive" organ-specific autoimmunity may be suggested both for the perpetuation of the autoimmune reaction (induction of efficient autoantigen presentation by TFC, via co-stimulatory molecules) and in induction of tissue damage via "suicide" Fas/FasL-mediated TFC interaction.

Cornea in acromegalic patients as a possible target of growth hormone action

BACKGROUND

GH exerts its effects on many organs and the eye also seems to be a target site, although few authors have investigated the corneal thickness in patients with acromegaly.

AIM

To perform a detailed ophthalmological evaluation in acromegalic patients, in relation to disease activity.

MATERIAL AND METHODS

Twenty-eight acromegalic patients (11 males, 17 females) and 22 voluntary healthy subjects underwent complete metabolic and ophthalmological evaluation, including retinal thickness (RT), central corneal thickness (CCT), and intraocular pressure values (IOP).

RESULTS

Significantly greater CCT values were found in all acromegalic patients in comparison with controls (567 vs 528.5 μm; p<0.001), without concomitant greater corrected IOP. No difference was found for RT. Analyzing these data according to disease activity, uncontrolled patients showed greater CCT values (573.5 vs 559 μm; p=0.002) and corrected IOP (17.4 vs 16 mmHg; p=0.001) than the controlled ones. CCT also correlated with basal and nadir GH after oral glucose load levels, IGF-I levels, and duration of active disease.

CONCLUSIONS

Acromegaly is characterized by greater CCT values, supporting the hypothesis that GH excess may have stimulatory effects on the cornea as well as on other target organs. Higher GH levels, disease control status and duration of active disease seem to be the main causes of increased corneal thickness. We suggest a careful and detailed corneal evaluation in acromegalic patients to prevent the potential risk of increased IOP, in addition to the already-known complications.

Influences of obesity and weight loss on thyroid hormones. A 3-3.5-year follow-up study on obese subjects with surgical bilio-pancreatic by-pass

The effects of changing body size, energy intake and substrate oxidation on serum T4, FT4, T3, FT3 and TSH were investigated in ten morbidly obese subjects (4 men/6 women; age: 37 +/- 6 years; BMI: 53.8 +/- 6.5 kg/m2; mean +/- SD) who had undergone a surgical bilio-pancreatic by-pass in order to reduce their body weight. The starting value of serum FT3 was inversely related to the BMI (r = -0.63; p < 0.05). After 1-3 months, all the subjects were losing weight and their intake of carbohydrates was almost negligible; at this time a significant reduction of T3 (-14.6%; p < 0.0001), T4 (-19.5%; p < 0.0001), and FT3 (-10.5%; p < 0.001) was observed. Nine to 16 months after surgery, all the subjects were still losing weight, although there was no carbohydrate restriction; T3, T4, and FT3 were lower than prior to surgery but were beginning to increase. Finally, after 36-42 months the body weight of all the patients had been stable for at least the previous six months (final BMI: 32.9 +/- 4.1) and their body composition, as assessed by bio-impedance, was almost normal; only the concentrations of FT3 proved to be significantly lower than the basal value (-11.2%; p < 0.03). The change in FT3 proved to be independently influenced by the degree of fat malabsorption but not by changes in any of the physical characteristics considered. All values were always in the normal range; FT4 and TSH did not change significantly during the whole period of study. The final concentrations of TSH proved to be independently related to the postabsorptive protein oxidation (g/24h) (TSH = 2.37-0.018* protein oxidation). These results would suggest that nutritional factors have some influence on the blood levels of thyroid hormones, especially of FT3, while the removal of obesity does not seem to have any independent effect in the long-run.

Defective expression of the apoptosis-inducing CD95 (Fas/APO-1) molecule on T and B cells in IDDM

Triggering of CD95 (Fas/APO-1) cell surface receptors regulates the elimination of autoreactive T and B lymphocytes through a mechanism of cell suicide called apoptosis. Three different mutations involving CD95 or its ligand are responsible for induction of autoimmunity in susceptible mouse strains. To determine whether a defect involving the CD95 receptor is associated with human insulin-dependent diabetes mellitus (IDDM), we have studied the expression of CD95 on peripheral blood mononuclear cells from IDDM patients at different stages of the disease. Three-colour flow cytometry and mean fluorescence analysis showed that T and B lymphocytes from newly diagnosed IDDM and patients with long-standing disease, and subjects at high risk of developing the disease were highly defective in CD95 expression (p < 0.001), whereas monocytes from all the groups studied expressed normal amounts of CD95 molecules on their cell surface. T-cell subset analysis showed that the impairment of CD95 expression in IDDM patients and high-risk subjects involved both CD3+ CD4+ (p < 0.001) and CD3+ CD8+ cells (p range: < 0.01-0.001), suggesting that this alteration concerns both helper and cytotoxic T cells. Moreover, after activation in vitro with anti-CD3 monoclonal antibody, T cells from newly diagnosed IDDM patients maintained a reduced CD95 expression during the entire cell culture period (24-72 h) in comparison to the control population (p < 0.001). In conclusion, we found a reduced expression of the apoptosis-inducing CD95 receptor on T and B lymphocytes of individuals with clinical and preclinical IDDM. We hypothesize that this defective expression may impair the capacity of autoreactive lymphocytes to undergo CD95-mediated apoptosis, contributing to the lack of control on beta-cell specific B- and T-cell clones.

Immunoregulatory T-lymphocyte subset deficiency in newly diagnosed type 1 (insulin-dependent) diabetes mellitus

Humoral and cell-mediated disorders in Type 1 (insulin-dependent) diabetes suggest that an imbalance of immunoregulatory T-cell subsets exists. In 23 newly diagnosed (onset less than 3 months) and 21 long-standing Type 1 diabetic patients, T lymphocyte subsets were analyzed using monoclonal antibodies (OKT3, OKT4, OKT8, OKM1). The newly diagnosed patients showed a reduction with a significant difference from healthy controls in total T cells (OKT3+: 58.1 +/- 8.5% versus 70.7 +/- 8.0%), helper/inducer cells (OKT4+: 33.8 +/- 7.0% versus 47.1 +/- 8.3%), suppressor/cytotoxic cells (OKT8+: 18.5 +/- 7.3% versus 32 +/- 6.8%) and monocytes (OKM1+: 11.5 +/- 3.8% versus 19.9 +/- 5.2%) (p less than 0.001). The long-standing diabetic patients also revealed a low number of immunoregulatory T cells compared with control subjects, although to a lesser extent (p less than 0.01-0.05). The helper/suppressor ratio (OKT4+/OKT8+) was higher in newly diagnosed patients than in control subjects (2.2 +/- 1.3 versus 1.5 +/- 0.3; p less than 0.02). When compared with 95% tolerance limits in the control subjects, the reduction of OKT8+ cells in the newly diagnosed diabetic patients appeared more marked: the mean (18.5%) coincided with the lower limit of normal subjects (18.3%). Ten of the newly diagnosed Type 1 diabetic patients had a value below the normal lower limit. Out data point to the occurrence of different immunoregulatory abnormalities in newly diagnosed Type 1 diabetic patients, especially in OKT8+ and OKT4+ cells. The imbalance in T lymphocyte subsets is further proof of the role of cellular autoimmunity in the pathogenesis of the early phases of Type 1 diabetes.

Visual evoked potentials in insulin-dependent diabetics

The latency of pattern-reversal VEPs was studied in type I insulin-dependent diabetics without retinal and extraocular involvement. One hundred eyes of 50 diabetics (mean age 19.8 +/- 7.2 years) formed the study group; the duration of the disease ranged between 1 month and 15 years. The latencies of VEPs were progressively delayed in relation to the duration of the disease, becoming more and more evident and stabilizing after about 6 years from the onset of diabetes. The VEP alterations probably indicate alteration of membrane balance or demyelinization.

Importance of premeal injection time in insulin therapy: Humalog Mix25 is convenient for improved post-prandial glycemic control in type 2 diabetic patients with Italian dietary habits

We investigated the use, in a short period, of Humalog Mix25 (Mix25) in a twice-daily administration regimen compared to a twice-daily injection therapy with Humulin 30/70 (30/70) in diabetic patients with Italian dietary habits. We studied 33 type 2 diabetic patients aged 59.1 +/- 8.1 years, BMI 29.8 +/- 2.7 kg/m2, duration of diabetes and insulin therapy of 14.4 +/- 9.8 and 4.2 +/- 4.6 years, respectively. After a 4-day lead-in period of twice-daily human insulin 30/70 treatment, patients were randomized to one of two treatment sequences: (1) a twice-daily regimen with Mix25 just 5 minutes before the morning and evening meals for 12 days, followed by a twice-daily therapy with human insulin 30/70 given 30 minutes before the morning and evening meals for an additional 12 days; or (2) the alternate sequence. Each patient underwent a mixed meal test: Humulin 30/70 was administered 30 minutes before the meal, while Mix25 was given 5 minutes before. The 2-hour post-prandial glucose concentration after breakfast was significantly lower during treatment with Mix25 than with Humulin 30/70 (157 +/- 43.2 vs. 180 +/- 43.2 mg/dl, p<0.05). The glycemic excursion after dinner on Mix25 treatment was significantly lower than with Humulin 30/70 (12.2 +/- 48.01 vs. 35.5 +/- 36.92 mg/dl, p<0.05). AUCglucose after Mix25 was lower than after Humulin 30/70. Glycemia after test meal was significantly lower with Mix25 than with Humulin 30/70. Insulin and free insulin concentrations after the test meal were significantly higher with Mix25 in comparison to Humulin 30/70. AUC serum insulin and free insulin curves after Mix25 were significantly higher than after Humulin 30/70 (p=0.028 and p=0.005, respectively). Twice-daily injections of Humalog Mix25, compared to human insulin 30/70 in type 2 diabetic patients with Italian dietary habits, provide improved and lasting post-prandial glycemic control, with the great convenience of the injection just before the meal.

Study of T-cell activation in type I diabetic patients and pre-type I diabetic subjects by cytometric analysis: antigen expression defect in vitro

In Type I diabetes the observation of a decreased release of interleukin-2 (IL-2) and soluble IL-2 receptors by means of stimulated lymphocytes in vitro indicates that a primary immunoregulatory defect may be involved. To confirm this hypothesis we investigated the T-cell activation trend, evaluating the surface expression of IL-2 receptor (CD25), transferrin (CD71), HLA class II (DR), and CD69 phenotypes after in vitro stimulation with phytohemagglutinin (PHA; 1 and 10 micrograms/ml) and concanavalin A (12.5 micrograms/ml) in six newly diagnosed Type I diabetics and six islet cell- and insulin autoantibody-positive first-degree relatives. As controls were studied six long-standing Type I diabetics and six healthy subjects. T-cell cultures from the four groups were performed on the same day and examined at 0, 24, 48, 96, 120, and 144 hr. Cytometric analysis was performed, keeping PBMC gating constant on the basis of physical parameters (scatter and volume). Using both PHA concentrations, a lower level of CD25, CD71, CD69, and DR antigen expression was found in newly diagnosed patients at all observation times with respect to control cultures (P < 0.001). Unexpectedly, pre-Type I diabetic subjects, after 1 microgram/ml of PHA, showed a significantly reduced expression of CD69 (P < 0.001) and CD71 (P < 0.001). The levels remained low, also with high PHA, at the different observation periods, while CD25 expression was found to be reduced in prediabetics only after 1 micrograms/ml of PHA (P < 0.001). The long-standing patients showed a T cell activation trend very close to the latter. Our data show that in Type I diabetes and in the early phases of the disease, the initial activation signal(s) appears to be affected, particularly with one or more subsequent events necessary to initiate the appearance of "activation antigens." This study suggests that the natural history of immunoregulation in pre-Type I and Type I diabetes is characterized by a primary defect in this system, which also persists in patients with long-standing disease.

Depression of CD4 T cell subsets and alteration in cytokine profile in boutonneuse fever

Interferon (IFN)-gamma, interleukin (IL)-10, IL-6, and tumor necrosis factor (TNF)-alpha were significantly increased in sera from Sicilian patients with acute boutonneuse fever (BF) compared with those of healthy controls. IFN-gamma levels dropped sharply within the second week after infection. IL-6, IL-10, and TNF-alpha levels gradually declined; in convalescent patients only were they in the normal range. In contrast, peripheral blood mononuclear cells (PBMC) stimulated in vitro with phytohemagglutinin (PHA) produced low levels of IL-10 and IFN-gamma in acute BF that were compatible with the reduction in the levels of CD4+, CD4+/CD45RO+, and CD4+/CD45RA+ cells. In vitro production of TNF-alpha and IL-6 from PBMC stimulated with PHA was not significantly modified during the various phases of the infection compared with control PBMC, which could be due to the persistence of high levels of CD14+ monocytes compensating for the decrease in CD20+ B cells.

Defective expression of CD95 (FAS/APO-1) molecule suggests apoptosis impairment of T and B cells in HLA-B8, DR3-positive individuals

Activation-induced apoptosis is one of the primary control mechanisms for the negative selection of an immune response, leading to maintenance of immune homeostasis and selective T cell deletion. The interaction between the surface molecule Fas and its ligand (FasL) has been proposed as a primary mechanism initiating T cell apoptosis. The T cell receptor modulates the expression and function of these molecules. Defects in the Fas/FasL apoptosis pathway have been shown to result in autoimmune disease in humans and in murine models. Because subjects carrying the HLA-B8, DR3 haplotype show a number of immune dysfunctions, including membrano-proliferative glomerulonephritis, systemic lupus erythematosus, Graves' disease, and others, we investigated Fas expression on T and B cells, and sensitivity to Fas-mediated apoptosis of activated T cells, to determine whether abnormalities of the Fas pathway might be associated with the development of autoimmune diseases in this group of individuals. Our findings show that B cells and resting T cells from HLA-B8+, DR3+ subjects express markedly reduced levels of Fas compared with those isolated from HLA-B8-, DR3+ individuals. Reduced levels of Fas were also evident on the surface of T cells from HLA-B8+, DR3+ subjects activated in vitro by stimulation with OKT3 and phytohemoagglutinin. Cycling T cells from these subjects, evaluated for apoptotic nuclei by flow cytometry after incubation with a cytolytic anti-Fas mAb, showed a significantly lower percentage of Fas-mediated apoptosis than did those from HLA-B8-, DR3- individuals. Normal levels of apoptosis were restored after exposure to a synthetic ceramide analog (C2). Further elucidation of the interaction of these molecules in autoimmune diseases may lead to better understanding of the pathogenesis of these disorders.

Low bcl-2 expression and increased spontaneous apoptosis in T-lymphocytes from newly-diagnosed IDDM patients

The bcl-2 gene product has been shown to regulate apoptotic cell death, and its dysregulation has been shown to induce several abnormalities in the immune system. No data exist regarding bcl-2 expression in autoimmune diseases, such as human insulin-dependent diabetes mellitus (IDDM). We investigated bcl-2 protein expression by testing T lymphocytes from 15 newly-diagnosed (< 3 weeks) IDDM patients in comparison to 10 age-matched control subjects. The expression of bcl-2 on CD3+ lymphocyte subsets was investigated after membrane permeabilization by two- or three-colour immunofluorescence. When the percentage and mean fluorescence intensity (MFI) of bcl-2+/CD3+ cells from normal individuals and patients were compared, we found that bcl-2 expression within the CD3+ and CD4+ CD45R0+ T-cell populations was reduced significantly in IDDM patients (46.8 +/- 15.4 vs 79.6 +/- 11.7; 25.7 +/- 3.8 vs 47.15 +/- 5.7, respectively; p < 0.001). To establish whether low bcl-2 expression in T cells from newly-diagnosed patients reflects their susceptibility to death by an apoptotic process, we also evaluated DNA staining with propidium iodide in CD3+ lymphocyte suspension after a (24-72 h) culture period (spontaneous apoptosis). We found that IDDM patients have higher levels of spontaneous apoptosis (mean +/- SEM: 24 h = 4.6 +/- 0.8; 48 h = 9.9 +/- 1; 72 h = 12.8 +/- 1.1) than control subjects (24 h = 1.8 +/- 0.4; 48 h = 4.6 +/- 0.4; 72 h = 5.7 +/- 0.3; p < 0.02-0.001). Our study suggests that recent onset IDDM is characterised by reduced bcl-2 expression, which in turn may be associated with the increased spontaneous apoptosis we observed.

No independent association between HSP70 gene polymorphism and IDDM

A role for heat shock proteins (HSPs) in autoimmunity has recently been suggested by several authors. Autoantibodies against HSPs have been associated with such autoimmune diseases as systemic lupus erythematosus, polymyositis, and the NOD mouse model of diabetes. Moreover, genes for the major 70,000-M(r) HSP (HSP70) are located within the MHC. To investigate a potential association of an HSP70-2 gene polymorphism with insulin-dependent diabetes mellitus (IDDM), we analyzed restriction-fragment-length polymorphism (RFLP) of this gene in 29 families with one or more member affected by IDDM. With the enzyme PstI, as reported previously, two HSP70-2 alleles of 8.5- and 9.0-kb were found. The 8.5-kb allele was found more frequently on diabetic haplotypes compared with control haplotypes (41 of 66 [62%] vs. 20 of 46 [43%], P = 0.03). This association was due to the conservation of alleles on extended haplotypes we previously reported to be associated with diabetes on initial analysis of families. Twenty-three of 26 diabetic DR3 haplotypes and 3 of 3 normal DR3 haplotypes and all instances of [HLA-B8, SC01, DR3] and [HLA-B18, F1C30, DR3] had the 8.5-kb allele, whereas 0 of 9 normal DR2 haplotypes and 0 of 2 diabetic DR2 haplotypes had the 8.5-kb allele (P = 8 x 10(-7) DR3 vs. DR2 haplotypes). The alleles were equally distributed among DR4 haplotypes.(ABSTRACT TRUNCATED AT 250 WORDS)

Soluble interleukin-2 receptor secretion defect in vitro in HLA-B8, DR3 positive subjects

Several studies have shown that HLA-B8,DR3 positive subjects may display T cell dysfunctions. Recently, a soluble form of the receptor for IL-2 (sIL-2R) has been demonstrated in human sera and in vitro-stimulated culture supernatant from human T lymphocytes. In the present paper we report sIL-2R serum levels and sIL-2R production from peripheral blood mononuclear cells in HLA-B8,DR3 positive subjects. We found that HLA-B8,DR3 positive subjects have the highest values of serum sIL-2R, but comparing the values of these subjects with those of negative ones no significant difference was observed. As regards the in vitro production of sIL-2R, no difference exists for unstimulated cultures, whereas after stimulation, the HLA-B8,DR3 positive subjects showed the lowest values compared with negative ones. It is noteworthy that these changes are observed in autoimmune diseases linked to this HLA phenotype.