Vitamin D and autoimmune rheumatologic disorders. Autoimmun Rev. 2010;9:507-510. [PMID: 20146942 DOI: 10.1016/j.autrev.2010.02.011]

Vitamin D endocrine system involvement in autoimmune rheumatic diseases

Vitamin D is synthesized from cholesterol in the skin (80-90%) under the sunlight and then metabolized into an active D hormone in liver, kidney and peripheral immune/inflammatory cells. These endocrine-immune effects include also the coordinated activities of the vitamin D-activating enzyme, 1alpha-hydroxylase (CYP27B1), and the vitamin D receptor (VDR) on cells of the immune system in mediating intracrine and paracrine actions. Vitamin D is implicated in prevention and protection from chronic infections (i.e. tubercolosis), cancer (i.e. breast cancer) and autoimmune rheumatic diseases since regulates both innate and adaptive immunity potentiating the innate response (monocytes/macrophages with antimicrobial activity and antigen presentation), but suppressing the adaptive immunity (T and B lymphocyte functions). Vitamin D has modulatory effects on B lymphocytes and Ig production and recent reports have demonstrated that 1,25(OH)2D3 does indeed exert direct effects on B cell homeostasis. A circannual rhythm of trough vitamin D levels in winter and peaks in summer time showed negative correlation with clinical status at least in rheumatoid arthritis and systemic lupus erythematosus. Recently, the onset of symptoms of early arthritis during winter or spring have been associated with greater radiographic evidence of disease progression at 12 months possibly are also related to seasonal lower vitamin D serum levels.

Associations of vitamin d binding protein gene polymorphisms with the development of peripheral arthritis and uveitis in ankylosing spondylitis

OBJECTIVE

Genetic factors account for more than 90% of overall susceptibility to ankylosing spondylitis (AS), and recent studies have focused on non-major histocompatibility complex genes. Vitamin D binding protein (DBP) is a highly polymorphic protein that transports vitamin D and its metabolites. In addition to its sterol binding capacity, DBP has many other roles in the inflammatory and immune systems, and has been reported to be associated with autoimmune diseases. We investigated the association between DBP polymorphisms and susceptibility to AS.

METHODS

This case-control study was conducted in 223 patients with AS and 239 ethnically matched controls who were genotyped for 8 single-nucleotide polymorphisms (SNP) in the DBP and its promoter. Genomic DNA was isolated from peripheral blood leukocytes using the standard phenolchloroform method, and the GoldenGate assay was used for genotyping.

RESULTS

No significant association was found between the susceptibility to AS and DBP polymorphisms. In a subgroup analysis of patients with AS, G alleles at rs222016 and rs222020 (OR 0.63, 95% CI 0.42-0.95, p = 0.03; OR 0.63, 95% CI 0.42-0.95, p = 0.03, respectively) and A allele at rs3733359 (OR 0.59, 95% CI 0.39-0.90, p = 0.01) showed the decreased risk of peripheral arthritis. G allele at rs4752 showed increased risk of uveitis (OR 2.04, 95% CI 1.12-3.72, p = 0.02). On the haplotype analyses, haplotype 2 (AGGA) protected against the development of peripheral arthritis (p = 0.01) and haplotype 3 (GAAG) was associated with an increased likelihood of uveitis (p = 0.02).

CONCLUSION

DBP gene polymorphisms are associated with the development of peripheral arthritis and uveitis in Korean patients with AS. Given the influence of different DBP variants on the immune system, larger-scale studies are warranted to elucidate the role of DBP in the pathogenesis of AS.

Adulthood residential ultraviolet radiation, sun sensitivity, dietary vitamin D, and risk of lymphoid malignancies in the California Teachers Study

To lend clarity to inconsistent prior findings of an inverse association between ultraviolet radiation (UVR) exposure and risk of lymphoid malignancies, we examined the association of prospectively ascertained residential ambient UVR exposure with risk of non-Hodgkin lymphomas (NHLs), multiple myeloma (MM), and classical Hodgkin lymphoma in the California Teachers Study cohort. Among 121 216 eligible women, 629 were diagnosed with NHL, 119 with MM, and 38 with Hodgkin lymphoma between 1995-1996 and 2007. Cox proportional hazards regression was used to estimate incidence rate ratios (RRs) with 95% confidence intervals (CIs). Residential UVR levels within a 20-km radius were associated with reduced risk of overall NHL (RR for highest vs lowest statewide quartile of minimum UVR [≥ 5100 vs < 4915 W-h/m(2)], 0.58; 95% CI, 0.42-0.80), especially diffuse large B-cell lymphoma (RR, 0.36; 95% CI, 0.17-0.78) and chronic lymphocytic leukemia/small lymphocytic lymphoma (RR, 0.46; 95% CI, 0.21-1.01), and MM (RR for maximum UVR, 0.57; 95% CI, 0.36-0.90). These associations were not modified by skin sensitivity to sunlight, race/ethnicity, body mass index, or neighborhood socioeconomic status. Dietary vitamin D also was not associated with risk of lymphoid malignancies. These results support a protective effect of routine residential UVR exposure against lymphomagenesis through mechanisms possibly independent of vitamin D.

Dietary factors regulate cytokines in murine models of systemic lupus erythematosus

Cytokines play the active roles in the pathogenesis of systemic lupus erythematosus (SLE) and contribute significantly to the immune imbalance in this disease. Conservative therapeutic approaches, such as dietary modifications have been shown to have some beneficial impact on the disease activity of the SLE. Over the past years, accumulating evidences have supported a major role for specific dietary factors, including calorie restriction, n-3/n-6 fatty acids, vitamin A, vitamin D, vitamin E, phytoestrogens or herbal medicine in the regulation of cytokines involved in SLE development. Although there are many reviews that discuss the issue of nutrition and immunity, there are relatively few articles that focus on the regulation of cytokines by dietary factors. This concise review will summarize those animal studies that investigated not only the outcome of autoantibody production and proteinuria, but also cytokines production. However, the field of dietary factors in the immunomodulation of SLE is still in its infancy. More clinical studies are needed to confirm the preliminary results and advance the knowledge in this field. Lifestyle modification and adjustments in diet are important and encouraged to be suggested as an adjuvant therapy for SLE.

Autoimmunity in 2010

There is now growing evidence that autoimmunity is the common trait connecting multiple clinical phenotypes albeit differences in tissue specificity, pathogenetic mechanisms, and therapeutic approaches cannot be overlooked. Over the past years we witnessed a constant growth of the number of publications related to autoimmune diseases in peer-reviewed journals of the immunology area. Original data referred to factors from common injury pathways (i.e. T helper 17 cells, serum autoantibodies, or vitamin D) and specific diseases such as multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis. As an example, the issue of a latitudinal gradient in the prevalence and incidence rates has been proposed for all autoimmune diseases and was recently coined as geoepidemiology to suggest new environmental triggers for tolerance breakdown. The present article is aimed at reviewing the articles that were published over the past year in the major autoimmunity and immunology journals.

Effects of vitamin D on the peripheral adaptive immune system: a review

Epidemiological studies have shown that a poor vitamin D status is associated with an increased risk of several diseases, including autoimmune diseases. The immune regulatory function of vitamin D is thought to have an important role in these associations. Cells of the adaptive immune system have shown to be direct targets of the vitamin D metabolites. Besides being direct targets, cells of the adaptive immune system express the enzymes involved in the metabolism of vitamin D, enabling them to locally convert 25(OH)D into its active metabolite 1,25(OH)2D. In this review, the effects of vitamin D on cells of the adaptive immune system are described. Experimental data in vitro show that vitamin D skews cells of the adaptive immune system toward a more tolerogenic status which might be exploited in the treatment of autoimmune diseases. However, it should be noticed that in vivo effects may differ from in vitro effects due to the cross-talk between different vitamin D sensitive cells, but data support the view that vitamin D is positively involved in maintaining or restoring immune homeostasis. Upcoming vitamin D supplementation trials will further elucidate the in vivo effects of vitamin D on the immune system and its potency to serve as an immune regulating agent in autoimmune diseases.

Serum 25-OH vitamin D concentrations are linked with various clinical aspects in patients with systemic sclerosis: a retrospective cohort study and review of the literature

Low vitamin D serum concentrations have been reported in several autoimmune conditions. The study's aim was to explore such a relationship in a large multinational population of patients with systemic sclerosis (SSc) and to pursue possible clinical and laboratory correlates with vitamin D concentrations. 327 sera samples of European patients with SSc and 141 samples of compatible healthy controls were studied for vitamin D concentrations using the commercial kit LIAISON 25-OH vitamin D assay (Diasorin). Additionally, clinical parameters including the Rodnan skin score, diffusing lung capacity for carbon monoxide (DLCO), systolic pulmonary artery pressure (sPAP), forced vital capacity (FVC), and nailfold video capillaroscopic, erythrocyte sedimentation rate (ESR), anti-nuclear antibodies (ANA and scl70), rheumatoid factor (RF) were investigated. Vitamin D serum concentration was 13.5 ± 9.0 ng/ml (mean ± standard deviation) in patients with SSc compared to 21.6 ± 9.7 ng/ml in a control group (p<0.001). A negative correlation between patients' age and vitamin D concentration (r = -0.2, p<0.05, n = 96) was observed. An inverse relationship was found between skin involvement and vitamin D serum concentrations; Patients with a Rodnan skin score of 10 or lower (n = 11) had a mean vitamin D concentration of 17.7 ± 10.4 ng/ml compared to patients with a score above 10 (n = 28) 8 ± 10.1 ng/ml (p=0.02, by the Mann-Whitney test). In conclusion, Patients with SSc have significantly lower serum vitamin D concentrations compared to healthy controls; moreover fibrosis of the cutaneous tissue is inversely related to the vitamin D concentration.

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.

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.