Control of autoimmune diseases by the vitamin D endocrine system

1,25-Dihydroxyvitamin D3 inhibits proliferation but not the suppressive function of regulatory T cells in the absence of antigen-presenting cells

Vitamin D3 is known to induce regulatory T (Treg) cells by rendering antigen-presenting cells tolerogenic, its direct effect on human naturally occurring Treg cells is unclear. Here, we investigated if and how 1,25-dihydroxyvitamin D(3) [1,25(OH)2D3] can directly affect the proliferation and function of human naturally occurring Treg cells in vitro. First, we demonstrated that these Treg cells express vitamin D receptors that were up-regulated following anti-CD3/CD28-bead stimulation. 1,25(OH)2D3 inhibited proliferation of Treg cells even when exogenous interleukin-2 was provided. Treg cells were more susceptible to the inhibitory effect of 1,25(OH)2D3 than conventional T cells(.) 1,25(OH)2D3 neither affected the anergic state nor the suppressive function of Treg cells but induced a subtle increase in interleukin-10-secreting cells. The cell-division-inhibiting effect of 1,25(OH)2D3 on Treg cells was also demonstrated in vivo by supplementing vitamin D-deficient HIV-1-infected patients with 2000 IU cholecalciferol (vitamin D3). Increased serum 1,25(OH)2D3 levels were associated with a drop in the number and percentage of Treg cells, which may be attributed to a decrease in the proliferating Foxp3+ Treg cell population. In conclusion, 1,25(OH)2D3 directly affects Treg cell growth and promotes interleukin-10 production without apparent effects on activation status and suppressive phenotype whereas in vivo, high serum 1,25(OH)2D3 levels are associated with reduced Treg cell proliferation and a reduced number of Treg cells.

Vitamin D deficiency is associated with mortality in the medical intensive care unit

Introduction

The incidence of vitamin D deficiency in critically ill patients has been reported to range from as low as 17% to as high as 79%. Data regarding the relationship between 25-hydroxyvitamin D levels and outcomes in the medical intensive care unit are sparse. The goal of the study was to evaluate the prevalence of 25-hydroxyvitamin D deficiency in the medical intensive care unit and its relationship with outcomes.

Method

This was a retrospective study in a medical intensive care unit (MICU) at an inner city community hospital. The study period was between October 2009 and February 2010.

Results

Of the 932 patients admitted during the study period, 25-hydroxyvitamin D vitamin D (25(OH)D) levels were available in 523 (53%); 86 of them were excluded from the study due to readmission to the intensive care unit. Deficiency was defined as 0 to 19.9 ng/dL 25(OH)D levels, insufficiency as 20 to 29.9 ng/dL, and normal levels as ≥30 ng/dL. Of the 437 patients studied, 25(OH)D deficiency was identified in 340 (77.8%), insufficiency in 74 (16.9%), and normal levels in 23 (5.3%) patients. Patients with 25(OH)D deficiency/insufficiency were younger (P = 0.015), were male (P = 0.001), and had kidney disease (P = 0.017) and lower total serum calcium levels (P = 0.003). Hospital mortality was higher in patients with 25(OH)D deficiency (P = 0.01). No differences in ventilator days or length of stay in the MICU were evident among the three groups. Analysis by multiple logistic regression demonstrated that acute physiology and chronic health evaluation (APACHE) IV score ((odds ratio (OR) 1.036; 95% confidence interval (CI) 1.024-1.048, P < 0.0001), ventilator requirement (OR 7.7; 95% CI 4.3-13.98, P < 0.0001), 25(OH) D levels(OR 0.942; 95% CI 0.942-0.904, P < 0.0005) and 25(OH) D deficiency (OR 8.7; 95% CI 1.03-72.8, P < 0.0469) showed statistical significance. There was no association between 25(OH)]D insufficiency and hospital mortality. The mean 25(OH)D level of survivors (27.9 ± 9.7 ng/dL) was higher than for non-survivors (9.7 ± 4.7 ng/dL; P < 0.0001).

Conclusions

The study results demonstrate an association between 25(OH)D deficiency and hospital mortality in MICU patients. A randomized prospective study to evaluate the effect of vitamin D replacement therapy on mortality is warranted.

Effects of 1,25(OH)2 vitamin D3 on cytokine production by endometrial cells of women with recurrent spontaneous abortion

OBJECTIVE

To investigate immunomodulatory effect of 1,25(OH)2 vitamin D3 (1,25(OH)2D3) on cytokine production by endometrial cells of women with unexplained recurrent spontaneous abortion (URSA).

DESIGN

In vitro study.

SETTING

Academic research center.

PATIENT(S)

Patients with URSA and healthy controls.

INTERVENTION(S)

Treatment with 1,25(OH)2D3.

MAIN OUTCOME MEASURE(S)

Production of interferon γ (IFN-γ), interleukin-10 (IL-10), transforming growth factor β (TGF-β), IL-17, IL-6, and IL-8 by whole endometrial cells (WECs) and endometrial stromal cells in the presence and absence of 1,25(OH)2D3 and 1α-hydroxylase activity of these cell populations were measured in patients with URSA and healthy controls.

RESULT(S)

1,25(OH)2D3 interfered with production of cytokines by WECs of the control and URSA groups, except IL-8 which was increased in URSA group. In endometrial stromal cells, 1,25(OH)2D3 down-regulated cytokine production as well with stimulatory effect on the production of TGF-β in patients with URSA. Cytokine profile of WECs from patients with URSA skewed toward TH2 phenotype after treatment with 1,25(OH)2D3. Endometrial cells of both groups had comparable capacity to produce 1,25(OH)2D3.

CONCLUSION(S)

Considering the complex network of immunoregulation at the fetomaternal interface, potential beneficial effects of vitamin D3 in patients with URSA need to be investigated in clinical practice. Comparable levels of 1,25(OH)2D3 production and similar trend of cytokine expression by WECs of URSA and control groups after vitamin D3 treatment reflect the same local metabolic machinery of this hormone.

Vitamin D deficiency as marker for disease activity and damage in systemic lupus erythematosus: a comparison with anti-dsDNA and anti-C1q

Objectives: To study the sensitivity and specificity of vitamin D deficiency for predicting disease activity and damage of systemic lupus erythematosus (SLE) in comparison with anti-dsDNA and anti-C1q. Methods: Consecutive patients who fulfilled four or more ACR criteria for SLE were studied. Levels of 25-hydroxyvitamin D3, anti-C1q, anti-dsDNA and complement levels were measured. Relationship among these markers, concurrent disease activity and damage scores of SLE was studied by Spearman's rank correlation method. Results: In total, 290 SLE patients were studied (95% women; mean age 38.9 ± 13.1 years; SLE duration 7.7 ± 6.7 years). Clinical or serological lupus activity (SLEDAI ≥ 1) was present in 225 (78%) patients. Vitamin D deficiency (< 15 ng/ml) was detected in 78 (27%) patients. Levels of 25-hydroxyvitamin D3 correlated inversely with the clinical SLE disease activity score (Rho = −0.26; p < 0.001). A negative correlation was also observed between 25-hydroxyvitamin D3 and anti-dsDNA levels (Rho = −0.13; p = 0.02), or anti-C1q (Rho = −0.14; p = 0.02). However, there was no significant relationship between levels of 25-hydroxyvitamin D3 and complement C3 (Rho = 0.09; p = 0.12) or C4 (Rho = 0.09; p = 0.13). Both 25-hydroxyvitamin D3 deficiency and anti-C1q were more specific but less sensitive than anti-dsDNA for concurrent clinical renal and non-renal SLE activity. Levels of 25-hydroxyvitamin D3, anti-dsDNA or anti-C1q did not correlate significantly with the SLE damage scores. Conclusions: 25-hydroxyvitamin D3 correlated inversely and significantly with clinical SLE activity, anti-C1q and anti-dsDNA titers, but not with complement levels or damage scores. Deficiency of 25-hydroxyvitamin D3 was as specific as anti-C1q, but less sensitive than anti-dsDNA, for detecting concurrent renal and non-renal clinical activity of SLE.

Expression of miR-146a and miR-155 in the urinary sediment of systemic lupus erythematosus

We studied the levels of miR-146a and miR-155 in the urine sediment of SLE patients. The levels of miR-146a and miR-155 in the urine sediment of 40 SLE patients who were receiving calcitriol treatment and 13 healthy controls were determined with real-time quantitative polymerase chain reaction. The levels of urinary miR-146a and miR-155 in patients with SLE were significantly higher than that in healthy controls. Calcitriol treatment reduced the levels of urinary miR-155 in patients with SLE. The level of urinary miR-146a significantly correlated with estimated glomerular filtration rate (r = 0.242, P = 0.008). The level of urinary miR-155 significantly correlated with proteinuria (r = 0.407, P < 0.001) and systemic lupus erythematosus disease activity index (r = 0.278, P = 0.002). The level of urinary miR-146a reversely correlated with the urinary expression of TNF-α (r = -0.247, P = 0.012). Our results suggested that miR-146a and miR-155 might play important roles in the pathophysiology of SLE and the levels of urinary miR-146a and miR-155 could be used as potential markers for diagnosis, disease activity, and therapeutic response.

Bone density in Moroccan women with systemic scleroderma and its relationships with disease-related parameters and vitamin D status

In this case-control study, our first aim was to evaluate the bone mineral density (BMD) in women with systemic sclerosis (SSc) and its correlates. Secondarily, we aimed to evaluate 25-hydroxyvitamin D3 status and its relationships with disease parameters and BMD. Sixty patients with SSc and 60 age-and gender-matched controls were included in the absence of confounding factors that interfere with bone metabolism. Body mass index, menopausal status, familial history of osteoporosis and/or fractures; personal fracture history; exercise activity and laboratory parameters of bone metabolism were assessed in patients and controls. BMD was measured by using a dual-energy X-ray absorptiometry in lumbar spine (L1-L4) and femoral neck. The 25-hydroxyvitamin D3 was measured in a subgroup of 30 patients and in a subgroup of 30 matched controls. Systemic manifestations of SSc, biological inflammatory parameters, functional disability (scleroderma health assessment questionnaire (S-HAQ)) and immunological status of disease were collected in patients' group. The mean age of patients was 49.44 ± 13.07 years versus 49.55 ± 12.11 in controls. The mean disease duration was 9.63 ± 5.9 years. SSc patients had a significantly earlier age and longer duration of menopause than controls (P = 0.003). Phosphocalcic metabolism parameters were within normal ranges in both groups. BMD was significantly lower in SSc patients than in controls both in lumbar spine (-2.97 ± 0.25 in patients vs. 0.46 ± 0.11 in controls) and femoral neck (-1.93 ± 0.32 in patients vs. -0.81 ± 0.69 in controls) (P < 0.01). Thirty-six (60%) patients versus 15 (25%) controls had osteoporosis and 19 (31.7%) patients versus 13 (21.7%) controls had osteopenia (P < 0.01). In correlation analysis and in multiple regression models, there were significant correlations between BMD and longer duration of SSc, severe joint involvement (severe joint pain and erosive arthropathy), malabsorption syndrome and the positivity of anti-DNA topoisomerase I antibodies. Also, we found very low levels of vitamin D (10.88 ± 2.68 ng/ml) comparing to controls (57.41 ± 4.18 ng/ml) (P = 0.001). Vitamin D levels were correlated with the severity of joint pain, with immunological status and with BMD in lumbar spine and femoral neck (P < 0.01). In our sample, we state the importance of decreased BMD in Moroccan women with SSc with a high frequency of osteoporosis comparing to healthy controls. Bone loss seems to be associated with prolonged disease duration, severe joint involvement, malabsorption syndrome and immunological status. Also, SSc patients had lower levels of 25-hydroxyvitamin D3 than controls. Larger studies are needed to confirm those findings.

Vitamin D deficiency is associated with an increased autoimmune response in healthy individuals and in patients with systemic lupus erythematosus

OBJECTIVES

Vitamin D deficiency is widespread and has been associated with many chronic diseases, including autoimmune disorders. A study was undertaken to explore the impact of low vitamin D levels on autoantibody production in healthy individuals, as well as B cell hyperactivity and interferon α (IFNα) activity in patients with systemic lupus erythematosus (SLE).

METHODS

Serum samples from 32 European American female patients with SLE and 32 matched controls were tested for 25-hydroxyvitamin D (25(OH)D) levels, lupus-associated autoantibodies and serum IFNα activity. Isolated peripheral blood mononuclear cells were tested for intracellular phospho-ERK 1/2 as a measure of B cell activation status.

RESULTS

Vitamin D deficiency (25(OH)D <20 ng/ml) was significantly more frequent among patients with SLE (n=32, 69%) and antinuclear antibody (ANA)-positive controls (n=14, 71%) compared with ANA-negative controls (n=18, 22%) (OR 7.7, 95% CI 2.0 to 29.4, p=0.003 and OR 8.8, 95% CI 1.8 to 43.6, p=0.011, respectively). Patients with high B cell activation had lower mean (SD) 25(OH)D levels than patients with low B cell activation (17.2 (5.1) vs 24.2 (3.9) ng/ml; p=0.009). Patients with vitamin D deficiency also had higher mean (SD) serum IFNα activity than patients without vitamin D deficiency (3.5 (6.6) vs 0.3 (0.3); p=0.02).

CONCLUSIONS

The observation that ANA-positive healthy controls are significantly more likely to be deficient in vitamin D than ANA-negative healthy controls, together with the finding that vitamin D deficiency is associated with certain immune abnormalities in SLE, suggests that vitamin D plays an important role in autoantibody production and SLE pathogenesis.

Vitamin D and immune function: an overview

Immunomodulatory actions of vitamin D have been recognised for over a quarter of a century, but it is only in the last few years that the significance of this to normal human physiology has become apparent. Two key factors have underpinned this revised perspective. Firstly, there are increasing data linking vitamin insufficiency with prevalent immune disorders. Improved awareness of low circulating levels of precursor 25-hydroxyvitamin D in populations across the globe has prompted epidemiological investigations of health problems associated with vitamin D insufficiency. Prominent among these are autoimmune diseases such as multiple sclerosis, type 1 diabetes and Crohn's disease, but more recent studies indicate that infections such as tuberculosis may also be linked to low 25-hydroxyvitamin D levels. The second factor expanding the link between vitamin D and the immune system is our improved knowledge of the mechanisms that facilitate this association. It is now clear that cells from the immune system contain all the machinery needed to convert 25-hydroxyvitamin D to active 1,25-dihydroxyvitamin D, and for subsequent responses to 1,25-dihydroxyvitamin D. Mechanisms such as this are important for promoting antimicrobial responses to pathogens in macrophages, and for regulating the maturation of antigen-presenting dendritic cells. The latter may be a key pathway by which vitamin D controls T-lymphocyte (T-cell) function. However, T-cells also exhibit direct responses to 1,25-dihydroxyvitamin D, notably the development of suppressor regulatory T-cells. Collectively these observations suggest that vitamin D is a key factor linking innate and adaptive immunity, and both of these functions may be compromised under conditions of vitamin D insufficiency.

Identification of novel immunoregulatory molecules in human thymic regulatory CD4+CD25+ T cells by phage display

Thymic CD4+CD25+ cells play an important role in immune regulation and are continuously developed in the thymus as an independent lineage. How these cells are generated, what are their multiple pathways of suppressive activity and which are their specific markers are questions that remain unanswered. To identify molecules involved in the function and development of human CD4+CD25+ T regulatory cells we targeted thymic CD4+CD25+ cells by peptide phage display. A phage library containing random peptides was screened ex vivo for binding to human thymic CD4+CD25+ T cells. After four rounds of selection on CD4+CD25+ enriched populations of thymocytes, we sequenced several phage displayed peptides and selected one with identity to the Vitamin D Receptor (VDR). We confirmed the binding of the VDR phage to active Vitamin D in vitro, as well as the higher expression of VDR in CD4+CD25+ cells. We suggest that differential expression of VDR on natural Tregs may be related to the relevance of Vitamin D in function and ontogeny of these cells.

Vitamin D receptor agonists inhibit pro-inflammatory cytokine production from the respiratory epithelium in cystic fibrosis

BACKGROUND

1,25-Dihydroxycholecalciferol (1,25(OH)(2)D(3)) has been shown to mitigate epithelial inflammatory responses after antigen exposure. Patients with cystic fibrosis (CF) are at particular risk for vitamin D deficiency. This may contribute to the exaggerated inflammatory response to pulmonary infection in CF.

METHODS

CF respiratory epithelial cell lines were exposed to Pseudomonas aeruginosa lipopolysaccharide (LPS) and Pseudomonas conditioned medium (PCM) in the presence or absence of 1,25(OH)(2)D(3) or a range of vitamin D receptor (VDR) agonists. Levels of IL-6 and IL-8 were measured in cell supernatants, and cellular total and phosphorylated IκBα were determined. Levels of human cathelicidin antimicrobial peptide (hCAP18) mRNA and protein were measured in cells after treatment with 1,25(OH)(2)D(3).

RESULTS

Pretreatment with 1,25(OH)(2)D(3) was associated with significant reductions in IL-6 and IL-8 protein secretion after antigen exposure, a finding reproduced with a range of low calcaemic VDR agonists. 1,25(OH)(2)D(3) treatment led to a decrease in IκBα phosphorylation and increased total cellular IκBα. Treatment with 1,25(OH)(2)D(3) was associated with an increase in hCAP18/LL-37 mRNA and protein levels.

CONCLUSIONS

Both 1,25(OH)(2)D(3) and other VDR agonists significantly reduce the pro-inflammatory response to antigen challenge in CF airway epithelial cells. VDR agonists have significant therapeutic potential in CF.

Vitamin D: evidence for its role as a prognostic factor in multiple sclerosis

Vitamin D insufficiency has been shown to be associated with increased susceptibility to multiple sclerosis (MS), but until recently, it was unclear if vitamin D status also influences the prognosis of the disease. In experimental autoimmune encephalomyelitis, a mouse model of MS, the administration of vitamin D reduces the severity of the disease. Initial reports in MS of inverse associations between vitamin D levels and disability or relapse rate were encouraging, but the cross-sectional or retrospective study designs limited their interpretability. More recently, studies of pediatric-onset and adult MS have demonstrated that among those with established MS, those with lower vitamin D levels are at higher risk for subsequent relapse. These observational data provide strong support for randomized controlled trials of vitamin D supplementation in MS.

Vitamin D regulation of immune function

Although the best known actions of vitamin D involve its regulation of bone mineral homeostasis, vitamin D exerts its influence on many physiologic processes. One of these processes is the immune system. Both the adaptive and innate immune systems are impacted by the active metabolite of vitamin D, 1,25(OH)(2)D. These observations have important implications for understanding the predisposition of individuals with vitamin D deficiency to infectious diseases such as tuberculosis as well as to autoimmune diseases such as type 1 diabetes mellitus and multiple sclerosis. However, depending on the disease process not all actions of vitamin D may be beneficial. In this review, I examine the regulation by 1,25(OH)(2)D of immune function, then assess the evidence implicating vitamin D deficiency in human disease resulting from immune dysfunction.

Vitamin D and inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are the main forms of inflammatory bowel disease (IBD), chronic relapsing-remitting inflammatory conditions of uncertain origin affecting the gastrointestinal tract. Much effort has recently been made both in defining the mechanisms underlying the development of IBD, and in broadening the spectrum of effective treatment. Substantial progress has been made in characterising immune-cell populations and inflammatory mediators in IBD. 1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], the bioactive form of Vitamin D(3), besides having well-known control findings of calcium and phosphorus metabolism, bone formation and mineralization, also has a role in the maintenance of immune- omeostasis. The immune-regulatory role of vitamin D affects both the innate and adaptive immune system contributing to the immune-tolerance of self-structures. Impaired vitamin D supply/regulation, amongst other factors, leads to the development of autoimmune processes in animal models of various autoimmune diseases, including IBD. The administration of vitamin D in these animals leads to improvement of immune-mediated symptoms. Future studies now need to focus on the potential of vitamin D and its derivatives as therapeutic adjuncts in the treatment of IBD.

Vitamin D-mediated immune regulation in multiple sclerosis

Although Vitamin D is best known as a modulator of calcium homeostasis, it also has immune modulating potential. A protective effect of Vitamin D on Multiple Sclerosis (MS) is supported by the reduced risk associated with sun exposure and use of Vitamin D supplements. Moreover, high circulating levels of Vitamin D have been associated with lower risk of MS. To gain more insight into putative regulatory mechanisms of Vitamin D in MS pathogenesis, we studied 132 Hispanic patients with clinically definite MS, 58 with relapsing remitting MS (RR MS) during remission, 34 RR MS patients during relapse, and 40 primary progressive MS cases (PP MS). Sixty healthy individuals matched with respect to place of residence, race/ethnicity, age and gender served as controls. Levels of 25(OH) Vitamin D and 1,25(OH)(2) Vitamin D, measured by ELISA were significantly lower in RR MS patients than in controls. In addition, levels in patients suffering relapses were lower than during remissions. By contrast, PP MS patients showed similar values to controls. Proliferation of both freshly isolated CD4+ T cells and MBP-specific T cells was significantly inhibited by 1,25(OH)(2) Vitamin D. Moreover, activated Vitamin D enhanced the development of IL-10 producing cells, and reduced the number of IL-6 and IL-17 secreting cells. Notably, VDR expression was induced by 1,25(OH)(2) Vitamin D in both activated and resting cells. Interestingly, T cells were able to metabolize 25(OH) Vitamin D into biologically active 1,25(OH)(2) Vitamin D, since T cells express 1α-hydroxylase constitutively. Finally, 1,25(OH)(2) Vitamin D also increased the expression and biological activity of IDO, triggering significant increase in the number of CD4+CD25+ T regulatory cells. Collectively, these findings suggest that 1,25(OH)(2) VitaminD plays an important role in T cell homeostasis during the course of MS, suggesting correction of its deficiency may be useful during treatment of the disease.

Vitamin D levels in Chinese patients with systemic lupus erythematosus: relationship with disease activity, vascular risk factors and atherosclerosis

OBJECTIVES

To study the relationship of 25(OH)D(3) level with disease activity, vascular risk factors and atherosclerosis in SLE.

METHODS

Consecutive patients who fulfilled four or more ACR criteria for SLE were recruited for assay of 25(OH)D(3) level. Disease activity was assessed by the SLEDAI and physicians' global assessment (PGA). Patients with vascular risk factors were screened for atherosclerosis at the coronary or carotid arteries. Correlation between 25(OH)D(3) levels and SLEDAI scores was studied by linear regression. The link between vascular risk factors, atherosclerosis and vitamin D deficiency was also examined.

RESULTS

A total of 290 SLE patients were studied [94% women; mean (s.d.) age 38.9 (13.1) years; disease duration 7.7 (6.7) years; 78% patients had clinical or serological lupus activity]. Two hundred and seventy-seven (96%) patients had vitamin D insufficiency [25(OH)D(3) < 30 ng/ml] and 77 (27%) patients had vitamin D deficiency (<15 ng/ml). Levels of 25(OH)D(3) correlated inversely with PGA (β -0.20; P = 0.003), total SLEDAI scores (β -0.19; P = 0.003) and subscores due to active renal, musculoskeletal and haematological disease. Subjects with vitamin D deficiency had significantly higher total/high-density lipoprotein (HDL) cholesterol ratio [3.96 (2.94) vs 3.07 (0.80); P = 0.02] and prevalence of aPLs (57 vs 39%; P = 0.007). Of 132 patients, 58 (44%) with vascular risk factors screened were positive for subclinical atherosclerosis. No association could be demonstrated between 25(OH)D(3) level and atherosclerosis, which was mainly associated with increasing age, menopause, obesity and hyper-triglyceridaemia.

CONCLUSIONS

In this large cross-sectional study of SLE patients, 25(OH)D(3) level correlates inversely with disease activity. Vitamin D deficiency is associated with dyslipidaemia. In patients with vascular risk factors, subclinical atherosclerosis is not associated with hypovitaminosis D.

Vitamin D deficiency and its association with disease activity in new cases of systemic lupus erythematosus

Evidence has shown a relationship between vitamin D deficiency and systemic lupus erythematosus (SLE). We evaluated the frequency of vitamin D deficiency and its association with disease activity in new cases of SLE. Women with newly diagnosed SLE, based on the American College of Rheumatology (ACR) criteria, were enrolled consecutively. Those receiving vitamin D supplements and postmenopausal women were not included. Disease activity was measured by the BILAG index (2004) and serum concentration of 25-hydroxyvitamin D (25[OH]D) was measured by radioimmunoassay method. Forty SLE patients with mean age of 25.3 ± 4.2 years were studied. Severe, moderate, and mild vitamin D deficiency, corresponding to serum 25[OH]D concentrations of <12.5, 12.5-24.9, and 25-39.9  nmol/l, were found in 12.5%, 62.5%, and 17.5% of the patients, respectively. Serum 25[OH]D concentration was inversely correlated with the British Isles Lupus Assessment Group (BILAG) index score (r = -0.486, p = 0.001). Those with a more severe vitamin D deficiency had also higher concentrations of liver enzymes (p < 0.05), lower serum albumin and hemoglobin concentrations (p < 0.05), and higher titers of antibodies to double-stranded DNA (ds-DNA) (p < 0.001). This study showed that most of the SLE patients in our society have vitamin D deficiency at the time of diagnosis that is associated with a higher disease activity. Routine screening for vitamin D deficiency and its prompt treatment in patients with newly diagnosed SLE is recommended.

Predominance of Th2 polarization by vitamin D through a STAT6-dependent mechanism

Background

Vitamin D has several reported immunomodulatory properties including the reduced generation of pro-inflammatory CD4+ T helper 1 (Th1) cells and the increase in levels of the anti-inflammatory Th2 subset. Less clear has been the impact of vitamin D on the pro-inflammatory Th17 subset, and whether and how vitamin D may preferentially drive the polarization of one of the T helper subsets.

Methods

Using human peripheral blood-derived mononuclear cells and mouse splenocytes and lymph node cells in culture, we examined whether and how vitamin D preferentially skews T cells towards the Th1, Th2 or Th17 subsets. Mice afflicted with the multiple sclerosis-like condition, experimental autoimmune encephalomyelitis (EAE), were examined in vivo for the relevance of the tissue culture-derived results.

Results

We report that the biologically active form of vitamin D, 1,25-dihydroxyvitamin D3 {1,25(OH)2D3}, consistently generates human and murine Th2 cells in culture, frequently leaving unchanged the levels of Th1/Th17 cytokines. As a result, the ratio of Th2 to Th1 and Th17 is increased by 1,25(OH)2D3. The upregulation of Th2 to Th1 or Th17 subsets by 1,25(OH)2D3 is enabled by an increase of the GATA-3 transcription factor, which itself is promoted upstream by an elevation of the STAT6 transcription factor. In mice, the alleviation of EAE severity by 1,25(OH)2D3 is accompanied by elevation of levels of GATA-3 and STAT6. Significantly, the efficacy of 1,25(OH)2D3 in ameliorating EAE is completely lost in mice genetically deficient for STAT6, which was accompanied by the inability of 1,25(OH)2D3 to raise GATA-3 in STAT6 null lymphocytes.

Conclusions

These results of vitamin D promoting a Th2 shift through upstream GATA-3 and STAT6 transcription factors shed mechanistic understanding on the utility of vitamin D in MS.

Calcitriol stimulates prolactin expression in non-activated human peripheral blood mononuclear cells: breaking paradigms

Calcitriol, the hormonal form of vitamin D(3), exerts immunomodulatory effects through the vitamin D(3) receptor (VDR) and increases prolactin (PRL) expression in the pituitary and decidua. Nevertheless, the effects of calcitriol upon lymphocyte PRL have not been evaluated. Therefore, we investigated calcitriol effects upon PRL in resting and phytohemagglutinin-activated human peripheral blood mononuclear cells (PBMNC) and Jurkat T lymphoma cells. Immunoblots showed constitutive expression of the 50-kDa VDR species in activated PBMNC and Jurkat cells, while a 75-kDa species was recognized in both resting and activated-PBMNC. Only in resting PBMNC calcitriol significantly stimulated PRL expression in a dose-dependent manner. The positive control CYP24A1, a highly VDR-responsive gene, was stimulated by calcitriol, effect that was stronger in resting than in activated-PBMNC (P<0.05), and without effect in Jurkat cells. Calcitriol upregulation of PRL and CYP24A1 was significantly inhibited by the VDR antagonist TEI-9647. EMSA showed that resting PBMNC contain a protein that binds to DR3-type VDRE. Cell activation reduced basal CYP24A1 while induced CYP27B1, VDR and pregnane X receptor (PXR) expression. In summary, calcitriol stimulated PRL and CYP24A1 gene expression in quiescent lymphocytes through a VDR-mediated mechanism. Our results suggest that the 75-kDa VDR species could be participating in calcitriol-mediated effects, and that activation induces factors such as PXR that restrain VDR transcriptional processes. This study supports the presence of a functional VDR in quiescent lymphocytes, providing evidence to reevaluate the VDR paradigm that assumes that lymphocytes respond to calcitriol only after activation. Altogether, our results offer new insights into the mechanisms whereby PRL is regulated in immune cells.

Vitamin D receptor gene polymorphisms in multiple sclerosis patients in northwest Greece

Background

Polymorphisms of the vitamin D receptor (VDR) gene have been linked to both multiple sclerosis (MS) and osteoporosis. We examined the frequency of the Taq-I and Bsm-I polymorphisms of the vitamin D receptor (VDR) gene in 69 patients with MS and 81 age and sex-matched healthy individuals. Genotyping of Taq-I (rs731236) and Bsm-I (rs1544410) was performed using TaqMan^® SNP Genotyping Assay. All patients and controls had determination of body mass index (BMI), bone mineral density (BMD) and smoking history.

Results

The mean age of patients was 39 ± 10.5 years compared to 38.7 ± 10.7 years of the controls (p = 0.86), the BMI was 24.8 ± 4.2 kg/m² compared to 25.7 ± 4.8 kg/m² of the controls (p = 0.23), the BMD in the lumbar spine 0.981 ± 0.15 compared to 1.025 ± 013 of the controls (p = 0.06) and the total hip BMD was 0.875 ± 0.14 compared to 0.969 ± 0.12 of the controls (p < 0.001). There were no differences of the Taq-I (TT, CT, CC) and Bsm-I genotypes (GG, GA, AA) and allelic frequencies between MS and control individuals. Multivariate analysis also failed to show any association of the Taq-I and Bsm-I polymorphisms and MS or sex, BMI, BMD and smoking history.

Conclusions

This study suggests that the Taq-I and Bsm-I polymorphisms of the VDR gene are not associated with MS risk, BMI or BMD in the Greek population studied.

Environmental factors and thyroid autoimmunity

Thyroid autoimmune disease, a multifactorial organ-specific autoimmune disorder, is marking a constant increase worldwide. It is thought to be caused by multiple environmental factors triggering autoimmune response in genetically susceptible individuals, though the exact mechanisms linking environmental factors to thyroid autoimmunity are not as yet well understood. Nevertheless, there is increasing evidence that mainly nutritive factors and environmental pollution by metals and chemicals (e.g. organochlorines, pesticides) are the main factors in the present-day spread of this disease. This review presents an overview of the current knowledge regarding environmental factors, their association with genetics and their impact on the immune system.

1α,25(OH)2-3-epi-vitamin D3, a natural physiological metabolite of vitamin D3: its synthesis, biological activity and crystal structure with its receptor

Background

The 1α,25-dihydroxy-3-epi-vitamin-D₃ (1α,25(OH)₂-3-epi-D₃), a natural metabolite of the seco-steroid vitamin D₃, exerts its biological activity through binding to its cognate vitamin D nuclear receptor (VDR), a ligand dependent transcription regulator. In vivo action of 1α,25(OH)₂-3-epi-D₃ is tissue-specific and exhibits lowest calcemic effect compared to that induced by 1α,25(OH)₂D₃. To further unveil the structural mechanism and structure-activity relationships of 1α,25(OH)₂-3-epi-D₃ and its receptor complex, we characterized some of its in vitro biological properties and solved its crystal structure complexed with human VDR ligand-binding domain (LBD).

Methodology/Principal Findings

In the present study, we report the more effective synthesis with fewer steps that provides higher yield of the 3-epimer of the 1α,25(OH)₂D₃. We solved the crystal structure of its complex with the human VDR-LBD and found that this natural metabolite displays specific adaptation of the ligand-binding pocket, as the 3-epimer maintains the number of hydrogen bonds by an alternative water-mediated interaction to compensate the abolished interaction with Ser278. In addition, the biological activity of the 1α,25(OH)₂-3-epi-D₃ in primary human keratinocytes and biochemical properties are comparable to 1α,25(OH)₂D₃.

Conclusions/Significance

The physiological role of this pathway as the specific biological action of the 3-epimer remains unclear. However, its high metabolic stability together with its significant biologic activity makes this natural metabolite an interesting ligand for clinical applications. Our new findings contribute to a better understanding at molecular level how natural metabolites of 1α,25(OH)₂D₃ lead to significant activity in biological systems and we conclude that the C3-epimerization pathway produces an active metabolite with similar biochemical and biological properties to those of the 1α,25(OH)₂D₃.

Efficacy and mechanisms of action of vitamin D in experimental polyarthritis

Vitamin D (vit D) status has been linked to the occurrence and severity of auto-immune and inflammatory diseases. This study evaluates the effects of vit D status on adoptive transfer of adjuvant-induced arthritis (ATA). Rats maintained on diets replete or deficient in vit D3 received arthritogenic thoracic duct cells and were monitored for severity of arthritis. CD45(+) cells obtained by collagenase digestion of hind-paw synovium-rich tissues (SRTs) were analysed to observe the effects of dietary vit D3 on the inflammatory process. Arthritis was more severe in vitamin D-deficient (vit-D(-)) rats compared with vitamin D-replete (vit-D(+)) rats. Resolution was delayed in vit-D(-) rats compared with vit-D(+) rats, or rats fed standard chow. During the acute phase of ATA, numbers of CD45(+) cells were significantly increased in the SRTs of vit-D(-) rats compared with vit-D(+) rats. This increase involved T-cells, polymorphonuclear leukocytes, macrophages, dendritic cells (DCs) and MHC II(hi) cells that resemble activated monocytes. A major difference between the dietary groups was that most DCs at the peak of inflammation in vit-D(-) rats were CD4(-), whereas in convalescent vit-D(+) rats most expressed CD4. Multiple categories of genes expressed by DCs differed between deficient and replete rats, with deficiency being associated with relative upregulation of certain pro-inflammatory genes and replete status being associated with upregulation of genes associated with resolution of inflammation. The findings indicate that ATA is more severe and prolonged in vit-D deficiency, that vit-D deficiency promotes accumulation of CD4(-) DCs in synovium during ATA and that a gene-expression profile is likely to contribute to the observed increased severity and duration of arthritis.

Vitamin D and aging: beyond calcium and bone metabolism

BACKGROUND

Low serum 25-hydroxyvitamin D (25[OH]D) levels are common and may be associated with morbidity and mortality (and indeed with frailty more generally). This association is not restricted to the links between vitamin D and calcium and bone metabolism.

OBJECTIVE

To review the influences of vitamin D on the aging process other than those related to bone and calcium. Its effect on mortality is also assessed.

METHODS

The PubMed database was searched for English-language articles relating to vitamin D, using the following MeSH terms: vitamin D, mortality, cardiovascular diseases, and frailty. In addition, searches were carried out with Google.

RESULTS

Although some of the reported results have proved controversial, overall the evidence seems to support an association between low serum 25[OH]D levels and mortality rates (all-cause and cardiovascular). Frailty is a condition frequently associated with low serum 25[OH]D levels.

CONCLUSION

The aging process and mortality are associated with low vitamin D levels. Prospective controlled trials are warranted to determine whether vitamin D supplements can increase longevity and reduce the incidence of certain conditions.

The role of vitamin D in pulmonary disease: COPD, asthma, infection, and cancer

The role of vitamin D (VitD) in calcium and bone homeostasis is well described. In the last years, it has been recognized that in addition to this classical function, VitD modulates a variety of processes and regulatory systems including host defense, inflammation, immunity, and repair. VitD deficiency appears to be frequent in industrialized countries. Especially patients with lung diseases have often low VitD serum levels. Epidemiological data indicate that low levels of serum VitD is associated with impaired pulmonary function, increased incidence of inflammatory, infectious or neoplastic diseases. Several lung diseases, all inflammatory in nature, may be related to activities of VitD including asthma, COPD and cancer. The exact mechanisms underlying these data are unknown, however, VitD appears to impact on the function of inflammatory and structural cells, including dendritic cells, lymphocytes, monocytes, and epithelial cells. This review summarizes the knowledge on the classical and newly discovered functions of VitD, the molecular and cellular mechanism of action and the available data on the relationship between lung disease and VitD status.

Mechanism of 1α,25-dihydroxyvitamin D(3)-dependent repression of interleukin-12B

Interleukin 12 (IL-12) is a heterodimeric, pro-inflammatory cytokine that plays a central role in activation and differentiation of CD4(+) T cells into interferon-γ secreting T-helper type 1 cells. IL-12B, a gene encoding the larger subunit of active IL-12, has been reported to be down-regulated by the nuclear hormone 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)), but the mechanism of the regulation is unknown. In this study, we have examined the molecular mechanism of transcriptional regulation of the IL-12B gene by 1α,25(OH)(2)D(3) in lipopolysaccharide (LPS)-treated human monocytes (THP-1). Quantitative RT-PCR showed that IL-12B mRNA displays a cyclical expression profile and is down-regulated 2.8-fold during the first 8h and even 12.1-fold 24h after exposure to 1α,25(OH)(2)D(3). Gel shift and quantitative chromatin immunoprecipitation (ChIP) assays demonstrated vitamin D receptor (VDR) binding to genomic regions 480 and 6300bp upstream of the IL-12B transcription start site (TSS). Quantitative ChIP assays also revealed that together with VDR and its partner RXR the above regions recruited the co-repressor NCOR2/SMRT and histone deacetylase 3 leading to a decreased histone 4 acetylation and increased histone 3 trimethylation at the IL-12B promoter and its TSS. We suggest that these repressive epigenetic changes eventually cause down-regulation of IL-12 expression. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.

Efficient tetanus toxoid immunization on vitamin D supplementation

BACKGROUND/OBJECTIVES

Vitamin D mediates immunomodulatory functions, and its deficiency has been associated with an increased prevalence of immunological diseases. The supplementation of vitamin D might be therapeutically beneficial, for example, in lupus erythematosus patients. However, its affect on established recall immune responses is undefined.

SUBJECTS/METHODS

In all, 32 individuals were randomized in a placebo controlled, double-blind setting, and received vitamin D (daily 2000 IU) for 10 weeks followed by tetanus toxoid (TT) booster immunization.

RESULTS

During vitamin D supplementation the median 25-hydroxyvitamin D serum concentration increased to 80.3 nM, which as expected decreased in the placebo group to 29.1 nM during the ultraviolet-deprived winter months. The TT-specific immunoglobulin G (IgG) boost efficiency was marginal higher in the vitamin D group (P = 0.04). The increase of the 25-hydroxyvitamin D levels correlated with the increase of TT-IgG serum concentrations. The induction of specific serum IgA and specific antibody secreting cells was comparable between both groups. Accordingly, the TT-specific and polyclonally triggered T-cell cytokine profiles were stable as well.

CONCLUSIONS

Vitamin D supplementation was successful and booster immunization induced efficiently specific antibodies titers.

Vitamin D, disease and therapeutic opportunities

The discovery of the vitamin D endocrine system and a receptor for the hormonal form, 1α,25-dihydroxyvitamin D(3), has brought a new understanding of the relationship between vitamin D and metabolic bone diseases, and has also established the functions of vitamin D beyond the skeleton. This has ushered in many investigations into the possible roles of vitamin D in autoimmune diseases, cardiovascular disorders, infectious diseases, cancers and granuloma-forming diseases. This article presents an evaluation of the possible roles of vitamin D in these diseases. The potential of vitamin D-based therapies in treating diseases for which the evidence is most compelling is also discussed.

Vitamin D insufficiency defined by serum 25-hydroxyvitamin D and parathyroid hormone before and after oral vitamin D₃ load in Japanese subjects

Vitamin D insufficiency is a risk for both skeletal and nonskeletal health. However, some ambiguity remains about threshold serum 25(OH)D for vitamin D insufficiency. To determine the threshold serum 25(OH)D to maintain normal calcium availability without elevation in serum parathyroid hormone (PTH) among Japanese subjects with various calcium intakes, we conducted a multicenter prospective open-labeled study. We recruited 107 ambulatory subjects without disorders affecting vitamin D metabolism to whom oral vitamin D₃ 800 IU/day for 4 weeks or 1,200 IU/day for 8 weeks was given. Serum 25(OH)D, PTH, calcium, phosphate, and magnesium were measured before and after vitamin D₃ supplementation. Calcium intake was assessed by questionnaires. When all the data were combined, serum 25(OH)D was negatively correlated with PTH. The cubic spline curve between serum 25(OH)D and PTH indicated PTH reached its plateau between 35 and 40 pg/ml at 25(OH)D between 25 and 30 ng/ml. Vitamin D₃ supplementation increased serum 25(OH)D and decreased PTH. Change in PTH correlated positively with baseline serum 25(OH)D. From the regression analyses, baseline serum 25(OH)D above 28 ng/ml corresponded to the threshold level without reduction in PTH after vitamin D₃ supplementation. In multivariate regression analyses, age but not calcium intake was a significant determinant of PTH. We concluded that a serum 25(OH)D level of 28 ng/ml was identified as a threshold for vitamin D insufficiency necessary to stabilize PTH to optimal levels.

Vitamin D endocrine system and the immune response in rheumatic diseases

Epidemiological evidence indicates a significant association between vitamin D deficiency and an increased incidence of autoimmune diseases. The presence of vitamin D receptors (VDRs) in the cells of the immune system and the fact that several of these cells produce the vitamin D hormone suggested that vitamin D could have immunoregulatory properties, and now potent immunomodulatory activities on dendritic cells, Th1 and Th17 cells, as well as B cells have been confirmed. Serum levels of vitamin D have been found to be significantly lower in patients with systemic lupus erythematosus, undifferentiated connective tissue disease, and type-1 diabetes mellitus than in the healthy population. In addition, it was also found that lower levels of vitamin D were associated with higher disease activity in rheumatoid arthritis. Promising clinical results together with evidence for the regulation of multiple immunomodulatory mechanisms by VDR agonists represent a sound basis for further exploration of their potential in the treatment of rheumatic autoimmune disorders.

Vitamin D effects on lung immunity and respiratory diseases

Our understanding of vitamin D metabolism and biological effects has grown exponentially in recent years and it has become clear that vitamin D has extensive immunomodulatory effects. The active vitamin D generating enzyme, 1α-hydroxylase, is expressed by the airway epithelium, alveolar macrophages, dendritic cells, and lymphocytes indicating that active vitamin D can be produced locally within the lungs. Vitamin D generated in tissues is responsible for many of the immunomodulatory actions of vitamin D. The effects of vitamin D within the lungs include increased secretion of the antimicrobial peptide cathelicidin, decreased chemokine production, inhibition of dendritic cell activation, and alteration of T-cell activation. These cellular effects are important for host responses against infection and the development of allergic lung diseases like asthma. Epidemiological studies do suggest that vitamin D deficiency predisposes to viral respiratory tract infections and mycobacterial infections and that vitamin D may play a role in the development and treatment of asthma. Randomized, placebo-controlled trials are lacking but ongoing.

Vitamin D insufficiency in a large MCTD population

OBJECTIVES

The aim of the present study was to evaluate the vitamin D status in patients with mixed connective tissue disease (MCTD) and to determine which clinical symptoms, laboratory parameters and endothelial cell markers are associated with low vitamin D levels.

METHODS

125 female MCTD patients and 48 age- and sex-matched healthy controls were enrolled in the study. The clinical symptoms, autoantibodies (anti-U1-RNP, anti-cardiolipin - anti-CL and anti-endothelial cell antibody - AECA), serum cytokines (IFN-γ, IL-6, IL-12, IL-23, IL-17 and IL-10), soluble endothelial cell markers (endothelin, thrombomodulin - TM, and von Willebrand factor antigen - vWFAg) and serum lipids (total cholesterol, triglyceride, LDL-C, HDL-C, apolipoprotein A1, and apolipoprotein B) were investigated for an association with vitamin D levels by univariate and multivariate statistical analyses.

RESULTS

The mean vitamin D levels were significantly lower in MCTD patients, as compared with the control group (26.16±13.50ng/ml vs. 34.92±9.64ng/ml; p<0.001). In laboratory parameters, vitamin D levels were inversely associated with serum IL-6 (p<0.001), IL-23 (p=0.011), IL-10 (p=0.033) cytokine levels, TM (p=0.001) and endothelin (p=0.033) levels. Low vitamin D levels were also significantly associated with carotid artery intima media thickness (p<0.001), fibrinogen (p=0.010), total cholesterol (p=0.042) and ApoA1 (p=0.004) levels. Among the clinical symptoms, the cardiovascular involvement showed an inverse correlation with vitamin D status in MCTD (p<0.001).

CONCLUSIONS

The prevalence of vitamin D insufficiency is high in patients with MCTD. We assume that vitamin D insufficiency along with inflammatory parameters and lipid abnormalities may provoke cardiovascular events.

Does vitamin D affect risk of developing autoimmune disease?: a systematic review

OBJECTIVES

We evaluated the epidemiologic evidence that vitamin D may be related to human autoimmune disease risk.

METHODS

PubMed, limited to English from inception through April 2010, was searched using keywords: "vitamin D," "autoimmune," and autoimmune disease names. We summarized in vitro, animal, and genetic association studies of vitamin D in autoimmune disease pathogenesis. We sorted epidemiologic studies by design and disease and performed a systematic review of (a) cross-sectional data concerning vitamin D level and autoimmune disease; (b) interventional data on vitamin D supplementation in autoimmune diseases; and (c) prospective data linking vitamin D level or intake to autoimmune disease risk.

RESULTS

Vitamin D has effects on innate and acquired immune systems, and vitamin D receptor polymorphisms have been associated with various autoimmune diseases. In experimental animal models, vitamin D supplementation can prevent or forestall autoimmune disease. Of 1446 studies identified and screened, 76 studies examined vitamin D levels in autoimmune disease patients, particularly with active disease, and compared with controls. Nineteen observational or interventional studies assessed the effect of vitamin D supplementation as therapy for various autoimmune diseases (excluding psoriasis and vitiligo) with a range of study approaches and results. The few prospective human studies performed conflict as to whether vitamin D level or intake is associated with autoimmune disease risk. No interventional trials have investigated whether vitamin D affects human autoimmune disease risk.

CONCLUSIONS

Cross-sectional data point to a potential role of vitamin D in autoimmune disease prevention, but prospective interventional evidence in humans is still lacking.

Human prostatic urethra expresses vitamin D receptor and responds to vitamin D receptor ligation

BACKGROUND

Chronic inflammation is now considered a determinant of benign prostatic hyperplasia (BPH), promoting, together with the hormonal milieu, prostate overgrowth and lower urinary tract symptoms (LUTS). Prostatic urethra actively participates in determining progression of LUTS associated with BPH.

AIM

To investigate the expression of the vitamin D receptor (VDR) and the ability of the VDR agonist elocalcitol to reduce inflammatory responses in human prostatic urethra (hPU) cells.

MATERIALS AND METHODS

Human prostatic urethra, prostate and bladder neck were obtained from patients affected by BPH. Immunohistochemical studies for VDR expression were performed in tissue samples, from which primary cell cultures were also derived. In hPU cells, proliferation and chemiotaxis were studied, along with Rho kinase (ROCK) activity (MYPT-1 phosphorylation) by western blot. Quantitative RT-PCR was performed for VDR, cyclooxygenase (COX-2), and interleukin (IL)-8 expression.

RESULTS

Urethra displays higher VDR expression compared to prostate and bladder neck tissues. The VDR agonist elocalcitol partially reverts COX-2 and IL-8 mRNA upregulation induced by a pro-inflammatory cytokine mixture (IL-17, interferon-γ, tumor necrosis factor-α) and inhibits cell migration in urethral cells. Elocalcitol prevents activation of ROCK, as previously demonstrated in bladder and prostate cell cultures.

CONCLUSIONS

Our results suggest that prostatic urethra is, within the lower urinary tract, a novel target for VDR agonists, as shown by the capacity of elocalcitol to inhibit ROCK activity and to limit inflammatory responses in human primary urethra cells.

Serum and Urinary Cell–free MiR-146a and MiR-155 in Patients with Systemic Lupus Erythematosus

Objective.

Recent studies showed that micro-RNA play important roles in the pathogenesis of autoimmune diseases. We studied the levels of miR-146a and miR-155 in the serum and urinary supernatant of patients with systemic lupus erythematosus (SLE).

Methods.

The serum and urinary supernatant levels of miR-146a and miR-155 were determined by real-time quantitative polymerase chain reaction in 40 patients with SLE and 30 healthy controls.

Results.

Compared to controls, serum miR-146a and miR-155 levels were lower, and the urinary level of miR-146a was higher, in SLE. Estimated glomerular filtration rate (eGFR) correlated with both serum miR-146a (r = 0.519, p = 0.001) and miR-155 (r = 0.384, p = 0.014). Serum miR-146a inversely correlated with proteinuria (r = −0.341, p = 0.031) and the SLE Disease Activity Index (r = −0.465, p = 0.003). Serum miR-146a and miR-155 levels also correlated with red blood cell count, platelet count, and lymphocyte count. After treatment with calcitriol for 6 months, serum miR-146a level of SLE patients increased significantly (p < 0.001), and its change inversely correlated with the level of calcium-phosphate product (r = −0.466, p = 0.003).

Conclusion.

The results suggested that serum miR-146a and miR-155 participate in the pathophysiology of SLE and might be used as biomarkers of SLE.

Vitamin D status and clinical outcomes in incident dialysis patients: results from the NECOSAD study

BACKGROUND

The majority of dialysis patients suffer from vitamin D deficiency, which might contribute to an adverse health outcome. We aimed to elucidate whether European dialysis patients with low 25-hydroxyvitamin D (25(OH)D) levels are at increased risk of mortality and specific fatal events.

METHODS

This was a prospective cohort study of incident dialysis patients in the Netherlands (the NECOSAD). We selected all patients with measured 25(OH)D at 12 months after the start of dialysis, the baseline for our study. By Cox regression analyses, we assessed the impact of 25(OH)D levels on short-term (6 months of follow-up) as well as longer-term mortality (3 years of follow-up). Associations of 25(OH)D levels with cardiovascular and non-cardiovascular mortality were also determined.

RESULTS

The data from 762 patients (39% females, age 59 ± 15 years, 25(OH)D = 18 ± 11 ng/mL) were available. Fifty-one and 213 patients died during a follow-up of 6 months and 3 years, respectively. After adjustments for possible confounders, the hazard ratio (HR) (with 95% CI) for mortality was 2.0 (1.0-3.8) for short-term and 1.5 (1.0-2.1) for longer-term mortality when comparing patients with 25(OH)D levels ≤ 10 ng/mL with those presenting with 25(OH)D levels > 10 ng/mL. Adjusted HRs for cardiovascular mortality were 2.7 (1.1-6.5) and 1.7 (1.1-2.7) for short- and longer-term mortality, respectively. For non-cardiovascular mortality, we observed no relevant association overall. The impact of 25(OH)D levels on clinical events was modified by parathyroid hormone (PTH) status, with low 25(OH)D levels meaningfully affecting outcomes only in patients with PTH levels above the median of 123 pmol/L.

CONCLUSIONS

Vitamin D deficiency in dialysis patients is associated with an adverse health outcome, in particular with short-term cardiovascular mortality. Intervention studies are urgently needed to evaluate whether vitamin D supplementation improves health outcomes of dialysis patients.

Alfacalcidol treatment restores derailed immune-regulation in patients with undifferentiated connective tissue disease

Vitamin D deficiency may contribute to pathological changes in the number and function of CD4+ T helper cell subsets (CD4+Th1, CD4+Th17, CD4+CD25(bright)Foxp3-natural regulatory T cells-nTreg) in patients with undifferentiated connective tissue disease (UCTD). The aim of the present study was to evaluate, whether alfacalcidol could restore immune-regulatory changes in patients with UCTD. We assessed the optimal dose of alfacalcidol that could normalize the elevated levels of IFN-γ expressed by the CD4+Th1 cells and the IL-17 expressed by Th17 cells. Furthermore alfacalcidol decreased the Th1 and Th17 related cytokine levels, repaired the nTreg/Th7 balance, and restored the functional activity of nTreg cells. Twenty one UCTD patients with Vitamin D deficiency (<30 ng/ml) were administered with three different daily doses of alfacalcidol. Seven patients were supplemented with 0.5 μg/day, 7 patients with 1.0 μg/day, and 7 patients with 1.5 μg/day alfacalcidol treatment during 5 weeks. Our results indicated that 1.0 μg/day alfacalcidol during 5 weeks was the optimal therapeutic regime to increase the vitamin D levels, repair the nTreg/Th17 balance and raise the capacity of nTreg cells to suppress the proliferation of autologous CD4+CD25- cells. 1.5 μg daily dose alfacalcidol was not more effective than the 1.0 μg/day treatment. In this study we described that vitamin D deficiency can contribute to the complex immune-regulatory abnormalities in patients with UCTD and vitamin D substitution therapy can improve the fine balance of pro- and anti-inflammatory processes in the disease.

Upregulation of interleukin-1β production by 1,25-dihydroxyvitamin D(3) in activated human macrophages

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) plays important roles in the immune system. In contrast to its well known function in the adaptive immune system, much less is known about the immunoregulatory effects of 1,25(OH)(2)D(3) in the innate immune system, especially on activated human macrophages. Here we found that 1,25(OH)(2)D(3) strongly stimulated the production of interleukin-1β (IL-1β) in PMA-differentiated U937 cells and human monocyte-derived macrophages treated with lipopolysaccharide (LPS) or PMA. In this study, Erk1/2 appeared to mediate 1,25(OH)(2)D(3)-induced expression of IL-1β. Parallel to the increased production of IL-1β, 1,25(OH)(2)D(3) increased the expression and phosphorylation of the CCAAT enhancer-binding protein β (C/EBPβ), which is one of the key transcriptional regulatory factors for IL-1β transcription. These results suggest that 1,25(OH)(2)D(3) may function as a proinflammatory molecule in inflammatory macrophages.

SLE diagnosis and treatment: when early is early

Around 1980 antinuclear antibody testing became widely used in routine laboratory practice leading to a tapering in the lag time between SLE onset and diagnosis. Since then nothing relevant has been introduced which could help us in making the diagnosis of SLE earlier than now. Notably, there is increasing evidence that early diagnosis and treatment could increase SLE remission rate and improve patient prognosis. Although it has been shown that autoantibodies appear before clinical manifestations in SLE patients, currently we cannot predict which autoantibody positive subjects will eventually develop the disease. Thus, great effort should be made in order to identify new biomarkers able to improve our diagnostic potential. B lymphocyte stimulator (BLyS), anti-ribosomal P protein and anti-C1q antibodies are among the most promising. In recent years, some therapeutic options have emerged as appropriate interventions for early SLE treatment, including antimalarials, vitamin D, statins and vaccination with self-derived peptides. All these immune modulators seem to be particularly useful when introduced in an early stage of the disease.

Innovative management of lupus erythematosus

This article focuses on the management of discoid lupus erythematosus, subacute cutaneous lupus erythematosus, and systemic lupus erythematosus when the usual therapeutic arsenal such as oral antimalarial drugs and topical/oral steroids fail or provide insufficient treatment efficacy. Many of the treatments listed are the same or similar to each other because of similarities in the pathogenesis of various subtypes of cutaneous lupus. The clinical challenge is to determine the indications for topical versus systemic therapy, and to also identify the scenarios when combined therapy is necessary.

Is hypovitaminosis D one of the environmental risk factors for multiple sclerosis?

The role of hypovitaminosis D as a possible risk factor for multiple sclerosis is reviewed. First, it is emphasized that hypovitaminosis D could be only one of the risk factors for multiple sclerosis and that numerous other environmental and genetic risk factors appear to interact and combine to trigger the disease. Secondly, the classical physiological notions about vitamin D have recently been challenged and the main new findings are summarized. This vitamin could have an important immunological role involving a number of organs and pathologies, including autoimmune diseases and multiple sclerosis. Furthermore, human requirements for this vitamin are much higher than previously thought, and in medium- or high-latitude countries, they might not be met in the majority of the general population due to a lack of sunshine and an increasingly urbanized lifestyle. Thereafter, the different types of studies that have helped to implicate hypovitaminosis D as a risk factor for multiple sclerosis are reviewed. In experimental autoimmune encephalomyelitis, vitamin D has been shown to play a significant immunological role. Diverse epidemiological studies suggest that a direct chain of causality exists in the general population between latitude, exposure to the sun, vitamin D status and the risk of multiple sclerosis. New epidemiological analyses from France support the existence of this chain of links. Recently reported immunological findings in patients with multiple sclerosis have consistently shown that vitamin D significantly influences regulatory T lymphocyte cells, whose role is well known in the pathogenesis of the disease. Lastly, in a number of studies on serum levels of vitamin D in multiple sclerosis, an insufficiency was observed in the great majority of patients, including at the earliest stages of the disease. The questionable specificity and significance of such results is detailed here. Based on a final global analysis of the cumulative significance of these different types of findings, it would appear likely that hypovitaminosis D is one of the risk factors for multiple sclerosis.

Human T lymphocytes are direct targets of 1,25-dihydroxyvitamin D3 in the immune system

Besides its actions on minerals and bone, the bioactive vitamin D metabolite, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), has important immunomodulatory properties. Within the immune system, dendritic cells represent key targets for this hormone and 1,25(OH)2D3-induced changes in their phenotype and function ultimately affects T lymphocytes. However, the presence of vitamin D receptors (VDR) in activated T cells proposes additional mechanisms for 1,25(OH)2D3 to directly regulate T cell responses. Here, we investigated the expression and kinetics of vitamin D-related genes in human activated T lymphocytes. Different activation stimuli elicited increased VDR- and 1-alpha-hydroxylase expression, with a highly similar kinetic pattern. Addition of 1,25(OH)2D3 effectively triggered VDR signaling, as evidenced by 24-hydroxylase induction, but only when introduced to T lymphocytes expressing high levels of VDR. This enhanced degree of VDR signaling correlated with a stronger inhibition of cytokines (IFN-gamma, IL-10) and modulation of homing receptor expression (CCR10, CLA) in long-term T cell cultures. Importantly, chronic 1,25(OH)2D3-exposure further amplified VDR signaling and the concomitant T cell modulating effects. In conclusion, we validate T cells as direct targets for 1,25(OH)2D3 and provide this optimized in vitro model to improve our understanding of the role of vitamin D as a direct regulator of T cell responses.

Mycobacterium tuberculosis, autoimmunity, and vitamin D

Mycobacterium tuberculosis (TB) is a major cause of morbidity and mortality worldwide. Current anti-TB chemotherapies, although effective, are associated with side effects and are limited in treating drug-resistant strands. Autoimmune diseases are a leading cause of morbidity and mortality, with a growing mass of evidence implicating infections (e.g., TB) as their triggers. The burden of TB might further increase by reactivation threats hovering over millions harboring latent infection, thus, calling for novel approaches for this dire ailment. In recent years, the non-calcemic physiological actions of vitamin D have drawn a great deal of attention. In this review, we will focus on the role of vitamin D in the innate immune defense against TB on the one hand and conversely on the immunomodulatory effects of vitamin D on autoimmunity. Taken together, the suggested dual role of vitamin D in treating TB infection and possibly preventing associated autoimmunity will constitute the basis of the current review.