STAT-5 is activated constitutively in T cells, B cells and monocytes from patients with primary Sjögren's syndrome.

The expression and phosphorylation of signal transducer and activator of transcription-1 (STAT-1) have been shown to be markedly increased in the salivary gland epithelial cells of patients with primary Sjögren's syndrome (pSS). The present aim was to investigate the activation status of different STAT proteins in peripheral blood (PB) lymphocytes and monocytes, and their correlations with clinical parameters in patients with pSS. To this end, PB samples were drawn from 16 patients with active pSS and 16 healthy blood donors, and the phosphorylation of STAT-1, -3, -4, -5 and -6 proteins was studied in T cells, B cells and monocytes using multi-colour flow cytometry. In addition, mRNA expression of STAT molecules in PB mononuclear cells (PBMC) was studied with quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Basal phosphorylation of STAT-5 was found to be significantly higher in PB T cells, B cells and monocytes in patients with pSS than in healthy controls. The expression of STAT-5 mRNA was not increased in PBMC. pSTAT-5 levels in B cells and monocytes showed a significant correlation with serum immunoglobulin (Ig)G levels and anti-SSB antibody titres. Constitutive STAT-5 activation in monocytes and CD4(+) T cells was associated with purpura. There were no major differences in the activation of other STATs between pSS patients and healthy controls. In conclusion, STAT-5 is activated constitutively in PB leucocytes in patients with pSS, and basal STAT-5 phosphorylation seems to associate with hypergammaglobulinaemia, anti-SSB antibody production and purpura.

Serum amyloid A is independently associated with metabolic risk factors but not with early atherosclerosis: the Cardiovascular Risk in Young Finns Study.

BACKGROUND: Serum amyloid A (SAA) is a sensitive marker of inflammation and its elevation has been implicated in obesity and in cardiovascular disease, yet data on its regulation in young adults or on its role in early atherosclerosis is scarce. We investigated which factors explain the variation in SAA and analysed whether SAA could be associated with preclinical atherosclerosis. METHODS: Serum amyloid A levels were measured in participants of the Cardiovascular Risk in Young Finns Study (n = 2280, n = 1254 women, n = 1026 men). Correlates and determinants of SAA were analysed and the effect of SAA on subclinical atherosclerosis, measured as intima-media thickness (IMT) and carotid artery compliance, was evaluated with risk-factor adjusted models. RESULTS: Serum amyloid A correlated directly and independently of BMI with C-reactive protein (CRP), waist circumference and leptin in both sexes, with total cholesterol, LDL cholesterol and ApolipoproteinA1 (ApoA1) in women and with triglycerides, insulin levels and insulin resistance in men. Use of combined oral contraceptives and intrauterine device was also associated with SAA levels. Determinants for SAA included CRP, leptin and ApoA1 in women, and CRP, leptin and HDL cholesterol in men. SAA levels correlated with carotid compliance in both sexes and with IMT in men, yet SAA had no independent effect on IMT or carotid compliance in multivariable analysis. CONCLUSIONS: Serum amyloid A was associated with several metabolic risk factors but was not an independent predictor of IMT or carotid artery compliance. Further longitudinal studies will show whether SAA holds a prognostic value as a risk marker, analogously to CRP.

Indoleamine 2,3-dioxygenase activity associates with cardiovascular risk factors: the Health 2000 study.

Indoleamine 2,3-dioxygenase (IDO) is an important immunomodulator suppressing the activation of T lymphocytes, and its level in blood is increased in several autoimmune and inflammatory diseases. We have previously shown that this activity associates with several signs and risk factors of atherosclerosis in 24 to 39-year-old females. Now we repeat this analysis in an older population (n = 921, age range 46-76 years), i.e. in a population with more advanced atherosclerosis. IDO activity had a significant positive correlation in both sexes with carotid artery intima/media thickness (IMT), an early marker of atherosclerosis. In females, a significant negative correlation with HDL cholesterol and a positive correlation with triglycerides levels was observed. The association with IMT did not remain significant after adjustment with classical risk factors of atherosclerosis. It is thus concluded that IDO is a sensitive marker of atherosclerosis--or the inflammatory response associated with it--but does not have an independent role in the pathogenesis of this disease.

CRP gene is involved in the regulation of human longevity: a follow-up study in Finnish nonagenarians.

Chronic low-grade inflammation is involved in the pathogenesis of many disease conditions in humans and it is frequently quantified by measuring the blood concentration of C-reactive protein (CRP). Here we show that the CRP concentration in old people (nonagenarians) is, at least partially, genetically determined, and that the high producer genotype is associated with a shorter life expectancy during follow-up. Thus, the data imply that the CRP gene may be a longevity gene in humans.

Indoleamine 2,3-dioxygenase activity is increased in patients with systemic lupus erythematosus and predicts disease activation in the sunny season.

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-degrading enzyme which suppresses T lymphocyte activity. IDO activity can be determined by relating kynurenine, the main metabolite of tryptophan, to tryptophan (kyn/trp). We have demonstrated recently that systemic lupus erythematosus (SLE) is activated during the sunny season as measured by the European Consensus Lupus Activity Measurement Index (ECLAM) activity score. Our aim here was to establish whether IDO-dependent mechanisms are involved in the activation process of SLE. Kyn/trp was measured by reverse-phase high-performance liquid chromatography (HPLC) in 33 (30 female, three male) SLE patients in winter, spring and summer and in 309 healthy control subjects. At the same time-points the SLE patients were examined by a rheumatologist and a dermatologist and the activity of SLE assessed by the ECLAM score. IDO activity was higher in SLE patients than in healthy subjects. There was no seasonal variation in IDO activity in SLE patients and it did not correlate with the ECLAM activity score in winter. However, there was a significant correlation between IDO activity and the ECLAM score both in spring and in summer. High IDO activity in winter predicted subsequent activation of SLE in spring and summer. Our results indicate that IDO-dependent immunosuppressive mechanisms are activated in SLE patients. Exposure to sunlight or another factor causing seasonal variation in SLE activity leads to insufficiency of this suppression in a subgroup of patients, causing activation of SLE. High IDO activity in winter predicts activation of SLE in the sunny season.

Autoimmunity and longevity: presence of antinuclear antibodies is not associated with the rate of inflammation or mortality in nonagenarians.

There are reports demonstrating elevated levels of autoantibodies in elderly people. We now analyzed whether the strong inflammatory response associated with aging is interrelated with the production of autoantibodies, antinuclear antibodies (ANA). In a cohort of 284 nonagenarians the rate of ANA positivity was 12.3%, which is significantly (p<0.001) higher than that in the middle-aged controls (2.8%). The mortality data of this cohort was collected after a 4-year follow-up. The ANA positivity at the age of 90 did not have any effect on the rate of survival, or on the levels of serum markers of inflammation.

Indoleamine 2,3-dioxygenase enzyme activity correlates with risk factors for atherosclerosis: the Cardiovascular Risk in Young Finns Study.

Indoleamine 2,3 dioxygenase (IDO), an enzyme involved in the catabolism of tryptophan, suppresses T cell activity and is up-regulated by various inflammatory stimuli. The ratio of kynurenine, the main metabolite of tryptophan, to tryptophan (kyn/trp) reflects IDO activity. We calculated IDO activity and measured carotid intima-media thickness (IMT), a presymptomatic predictor of atherosclerosis, in 986 young adults (544 female, 442 male) for whom data on levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride, high sensitive C-reactive protein (CRP), body mass index (BMI), waist circumference, waist-to-hip ratio, systolic and diastolic blood pressure and smoking habits were available. IDO activity correlated significantly with IMT in female subjects, but not in males. In a multivariate linear regression model, IDO did not correlate independently with IMT in female subjects. However, IDO activity correlated significantly with several risk factors for atherosclerosis in females, i.e. with age, LDL-C, BMI, weakly with CRP and inversely with HDL-C and triglyceride. In males IDO activity correlated significantly with CRP and inversely with HDL-C. In conclusion, our results suggest that the IDO enzyme is involved in the immune regulation of early atherosclerosis, particularly in young female adults, and could constitute a novel marker of immune activation in early atherosclerosis in females.

Autoimmunity and atherosclerosis: functional polymorphism of PTPN22 is associated with phenotypes related to the risk of atherosclerosis. The Cardiovascular Risk in Young Finns Study.

There is a growing body of evidence attesting the significance of inflammation in the pathogenesis of atherosclerosis. Protein tyrosine phosphate PTPN22 C/T single nucleotide polymorphism (SNP) at + 1858 has been identified recently as a susceptibility factor for various inflammatory autoimmune diseases. We hypothesized that data on the genetic polymorphism of the PTPN22 enzyme associated with an increased risk of autoimmunity could also provide insight into the possible role of autoimmunity in the pathogenesis of atherosclerosis. Therefore we analysed the PTPN22 + 1858 C/T polymorphism in a population of young Finnish adults (n = 2268) for whom data on carotid artery intima-media thickness (IMT), a presymptomatic predictor of atherosclerosis, and risk factors for atherosclerosis were available. In males carriage of the T allele of PTPN22 + 1858 was associated significantly with IMT in univariate and multivariate analyses, while in females it was associated with several risk factors for atherosclerosis (BMI, waist circumference, waist-to-hip ratio, serum concentrations of C-reactive protein and triglycerides) but not with IMT. Our results indicate that the genetic polymorphism of PTPN22 + 1858 known to predispose to autoimmunity also enhances the development of atherosclerosis and thereby links the genetics of autoimmunity and atherosclerosis.

The activity of the immunoregulatory enzyme indoleamine 2,3-dioxygenase is decreased in smokers.

Indoleamine 2,3-dioxygenase (IDO), an enzyme involved in the degradation of the essential amino acid tryptophan (trp) to its main metabolite kynurenine (kyn), suppresses T cell activity. Smoking has marked immunomodulatory effects, above all immunosuppressive, causing a reduction in the levels of immunoglobulins and an increased risk of infections. The immunostimulatory effects of smoking are manifested, for example, in increased autoantibody production. We sought to establish whether IDO activity is involved in the immunomodulatory effects of smoking. To this end we measured the ratio of kyn to trp, reflecting IDO activity, by reverse-phase high-performance liquid chromatography (HPLC) in 784 (464 female, 230 male) subjects of a population-based sample of the adult Finnish population. Serum cotinine concentration as an indicator of active smoking was measured in the patients by radioimmunoassay and detailed data gathered on smoking habits. IDO activity was lower in smokers in this population-based sample compared with non-smokers when active smoking was classified according to serum cotinine concentration or history of smoking habits. Moreover, serum IDO activity correlated inversely with serum cotinine concentration. In conclusion, the activity of the IDO enzyme is decreased in smoking subjects, and the reduction in IDO-dependent immunosuppression could thus be responsible for the known immunostimulatory effects of smoking.

Indoleamine 2,3-dioxygenase activity in nonagenarians is markedly increased and predicts mortality.

Indoleamine 2,3-dioxygenase (IDO), an enzyme degrading tryptophan (trp) to kynurenine (kyn), suppresses T cell activity. Ageing of the immune system, immunosenescence, includes a decline in T cell function. We therefore sought to establish whether IDO activity is involved in immunosenescence and whether it predicts mortality in aged subjects. We measured kyn/trp, reflecting IDO activity, in 284 nonagenarians and 309 blood donor controls. IDO activity was significantly higher in nonagenarians compared with controls and IDO activity at study entry predicted subsequent mortality in nonagenarians. Thus, increased IDO activity might be a mechanism involved in the decline of T cell responses in immunosenescence.

Th2 cytokine genotypes are associated with a milder form of primary Sjogren's syndrome.

BACKGROUND: Immunohistological studies on salivary and lacrimal glands have yielded conflicting results on the Th1/Th2 balance in primary Sjögren's syndrome (pSS). OBJECTIVE: To establish whether pSS is a Th1 or Th2 directed autoimmune disease by analysing the polymorphism of the genes encoding for cytokines involved in the regulation of Th1/Th2 differentiation. METHODS: The polymorphisms of the genes encoding for interleukin 4 (IL4) -590 C/T, interleukin 13 (IL13) +2044 G/A, and interferon gamma (IFNG) +874 T/A were analysed in 63 white Finnish patients with pSS (61 female, two male) and in 63 healthy controls. The clinical and immunological data on the pSS patients were analysed in relation to these cytokine gene polymorphisms. RESULTS: There were no significant differences in the genotype or allele frequencies of IL4 -590, IL13 +2044, or IFNG +874 between pSS patients and controls. The erythrocyte sedimentation rate and concentrations of serum IgA and serum beta2 microglobulin were lower in pSS patients carrying the IL4 -590 T allele or the IL13 +2044 A allele than in those not carrying the respective alleles. The IL4 -509 T allele and IL13 +2044 A allele carriers less often had purpura than the corresponding non-carriers. CONCLUSIONS: The frequencies of the cytokine genotypes regulating Th1/Th2 differentiation did not differ between pSS patients and controls. However, the presence of cytokine genotypes with increased susceptibility to atopic and other Th2 diseases was associated with signs of a milder form of pSS. This finding would favour a hypothesis envisaging pSS as primarily a Th1 mediated autoimmune disease.

Mechanisms dependent on tryptophan catabolism regulate immune responses in primary Sjögren's syndrome.

To investigate the possible role of tryptophan metabolism in immune regulation of primary Sjögren's syndrome (pSS) the serum concentrations of tryptophan and its metabolite kynurenine were measured by reverse-phase high-performance liquid chromatography (HPLC) in 103 patients with pSS, 56 patients with sicca symptoms and 309 healthy blood donors. The kynurenine per tryptophan ratio (kyn/trp), which reflects the activity of the indoleamine-pyrrole 2,3-dioxygenase (IDO) enzyme involved in tryptophan catabolism, was calculated. Both female and male patients with pSS had significantly higher serum kynurenine concentrations and kyn/trp than subjects with sicca symptoms or healthy blood donors. The median (quartile range) concentration of kynurenine in female patients with pSS was 2.41 micromol/l (1.86-3.26) compared with 1.85 micromol/l (1.58-2.38, P < 0.0001) in subjects with sicca symptoms and 1.96 micromol/l (1.65-2.27, P < 0.0001) in healthy blood donors. Their kyn/trp x 1000 was 34.0 (25.1-44.3) compared with 25.3 (21.1-31.5, P < 0.0001) in subjects with sicca symptoms and 24.3 (21.0-28.9, P < 0.0001) in healthy blood donors. Female pSS patients with high IDO activity (kyn/trp x 1000 > or = 34.0) had significantly higher ESR, serum C-reactive protein, serum IgA and serum beta-2 microglobulin concentrations as well as higher serum creatinine levels, and they had positive antinuclear antibodies more frequently and presented with more American-European consensus group criteria than those with low IDO activity (kyn/trp x 1000 < 34.0). These data suggest that mechanisms dependent on tryptophan catabolism regulate immune responses in pSS. Tryptophan degradation is enhanced in patients with pSS, and high IDO activity is associated with severity of pSS.

Association of interferon-gamma +874(T/A) single nucleotide polymorphism with the rate of tryptophan catabolism in healthy individuals.

Abstract Mechanisms induced by tryptophan (trp) catabolism are important in the regulation of both normal and pathogenetic immune responses. The key enzyme is indoleamine-pyrrole 2,3-dioxygenase (EC 1.13.11.42) (IDO) which converts trp to kynurenine (kyn), the main toxic metabolite. It is known that interferon-gamma (IFN-gamma) is able to activate IDO. We wanted to analyse whether the strength of this mechanism would be under genetic control. To this end, we analysed the IFN-gamma+874(T/A) genotypes, which are known to have an effect on IFN-gamma production, of 309 healthy blood donors and correlated these to the levels of trp and kyn in their blood. The data obtained demonstrate that the presence of the high producer T allele was associated with increased IDO activity (i.e. elevated kyn and kyn/trp levels), but this effect was observed only in females. These data show that trp catabolism is genetically controlled by the IFN-gamma gene and may thus be operative in those disease conditions associated with the polymorphisms of the IFN-gamma gene.

Seasonal variation of disease activity of systemic lupus erythematosus in Finland: a 1 year follow up study.

OBJECTIVES: To study the role of different seasons in the disease activity of patients with systemic lupus erythematosus (SLE). Additionally, to evaluate whether the outdoor behaviour during the summer or a photoprovocation test affects disease activity. METHODS: 33 patients with SLE were examined by a rheumatologist and a dermatologist at a university hospital in winter, spring, and summer. The activity of SLE was assessed by the ECLAM index. Their outdoor behaviour was recorded by a questionnaire during the summer. In the winter, 12 patients were photoprovoked by ultraviolet A and B radiation on a small skin area. RESULTS: The ECLAM scores were higher in spring and tended to be higher in summer than in winter (p = 0.006 and p = 0.051). This finding, as well as the outdoor behaviour, were independent of the patients' own impression of their photosensitivity. Overall, the sun protection actions were inadequate. The photoprovocation had no statistical effect on disease activity, but one patient had a violent exacerbation of SLE manifestations shortly after the photoprovocation. CONCLUSIONS: In the northern climate SLE may be activated during the sunny season. Therefore, more effort should be focused on sun protection of patients with SLE.

Long-term follow-up study of pulmonary findings in patients with primary Sjögren's syndrome.

BACKGROUND: In a previous study pulmonary hyperinflation was observed frequently in patients with primary Sjogren's syndrome (pSS) and elevated serum beta-2 microglobulin (beta2m) concentrations were associated with hyperinflation. OBJECTIVE: To evaluate the significance of baseline serum beta2m concentration and to identify other possible risk factors for pulmonary involvement in long-term follow-up of patients with pSS. METHODS: Nineteen pSS patients whose pulmonary function tests (PFTs) had been previously studied were reexamined after a median follow-up of 10 years. Pulmonary symptoms were recorded, chest radiograph, and high-resolution computed tomography (HRCT) were evaluated and methacholine provocation and PFTs including flow-volume spirometry, body plethysmography, and diffusing capacity performed. RESULTS: Baseline serum beta2m concentrations correlated inversely with follow-up total lung capacity (TLC), vital capacity (VC), and diffusing capacity (DL), and positively with residual volume (RV), all expressed as percentage of predicted values. Diminished airways resistance (Raw) and, correspondingly, elevated specific conductance (SGaw) were frequent findings in pSS patients at follow-up, indirectly implying stiffness of the lungs and a restrictive decrease in lung volumes. Baseline serum protein concentration was higher and IgG concentration tended to be higher in pSS patients who at follow-up had elevated SGaw compared with others. Interstitial changes in HRCT were found more frequently in patients with elevated SGaw than in those without. CONCLUSION: Our results suggest that subtle restrictive changes in pulmonary function are more prone to develop in the long term in pSS patients with elevated serum beta2m concentration and other signs of immunological activity at baseline.

Matrix metalloproteinase 9 (MMP-9) gene polymorphism and MMP-9 plasma levels in primary Sjogren's syndrome.

OBJECTIVES: To determine whether plasma matrix metalloproteinase 9 (MMP-9) and MMP9 (-1562C-->T) polymorphism have an effect on the disease phenotype in primary Sjogren's syndrome (pSS). METHODS: Plasma MMP-9 concentrations and polymorphism of the MMP9 gene were analysed in 66 patients with pSS. These data were studied in relation to the clinical data of the patients. The genetic data of patients were compared with the data of 66 healthy subjects. RESULTS: Plasma MMP-9 was higher in patients with definite pSS than in patients with possible pSS. This association was principally caused by higher plasma MMP-9 in patients with a positive Schirmer test and keratoconjunctivitis sicca. pSS patients with purpura, SS-A autoantibodies and RF had significantly lower plasma MMP-9 than patients without these characteristics. The overall MMP9 (-1562C-->T) allele frequencies were similar in patients and control subjects. The frequency of the allele T was higher in patients without Raynaud's phenomenon than in the control group. CONCLUSIONS: MMP9 (-1562C-->T) could not be used for risk assessment in pSS. The presence of the rarer allele T may decrease the risk of Raynaud's phenomenon in pSS. High plasma MMP-9 is indicative of definite pSS but may paradoxically have a preventive effect on the eruption of purpura and on the development of autoantibody reaction in pSS.

Presence of apolipoprotein E epsilon4 allele predisposes to early onset of primary Sjogren's syndrome.

BACKGROUND: Apolipoprotein E (apoE) polymorphism plays a central role in lipid metabolism, but has recently also been suggested to regulate inflammation, as judged by levels of serum C-reactive protein (CRP). OBJECTIVE: To establish whether polymorphism of the apoE genes affects susceptibility to primary Sjogren's syndrome (pSS), degree of inflammation or age of onset of pSS. METHODS: ApoE genotype distribution and allelic frequencies were analysed using PCR and the TaqMan system in 63 Finnish Caucasian patients with pSS and in 64 healthy controls matched for sex, ethnic origin and area of residence. The clinical and immunological data on the pSS patients were analysed in relation to the apoE genotypes. RESULTS: There was no difference between pSS patients and controls in apoE genotype and allelic frequencies. The apoE epsilon4 allele was significantly associated with early onset of pSS in the entire population and in female patients (Kaplan-Meier log rank test, P = 0.0407 and P = 0.0168, respectively). The average age (+/- S.D.) of onset of pSS in all apoE epsilon4 allele carriers was 46 +/- 12 and in other genotypes it was 53 +/- 10 yr (P = 0.031, t-test). ApoE polymorphism was not associated with signs of inflammation evaluated by such markers as concentration of plasma CRP, plasma interleukin-6, plasma TNF-alpha, immunoglobulin G and haemoglobin, or leucocyte count or ESR. CONCLUSIONS: ApoE polymorphism does not affect susceptibility to pSS or levels of plasma inflammatory indices in patients with pSS. However, a clear association prevails between apoE epsilon4 and early onset of pSS.