Abnormal vitamin D3 metabolism in patients with primary Sjögren's syndrome

Vitamin D and Sjögren's Disease: Revealing the Connections-A Systematic Review and Meta-Analysis

BACKGROUND

The aim of the present review was to summarize the current evidence about the impact of vitamin D deficiency on pathology and clinical manifestations of Sjögren's disease (SD).

METHODS

Databases PubMed, Web of Science, Scopus, and Cochrane library were searched for studies assessing the levels of vitamin D in SD patients using the following keywords: (vitamin D OR calciferol OR cholecalciferol OR 25-hydroxyvitamin D OR 25-hydroxycholecalciferol OR calcidiol OR calcitriol OR 1,25-dihydroxycholecalciferol) AND (Sjögren's Syndrome OR Sjögren's disease) accessed on 20 September 2022. Out of 248 retrieved studies, following the systematic review methodology and defined inclusion and exclusion criteria, 9 clinical studies were eligible to be included in the present review: 4 of them case-control, 4 cross-sectional, and 1 cohort study.

RESULTS

Nine studies totaling 670 SD patients and 857 healthy controls were eligible for meta-analysis with moderate to high methodological quality as determined by the Newcastle-Ottawa Quality Scale (NOS). According to the obtained results, a high prevalence of hypovitaminosis D was observed in SD patients when compared to healthy controls (95% CI -10.43, -2.39; p < 0.01).

CONCLUSION

Available evidence points to lower levels of vitamin D in patients with SD in comparison to healthy controls. However, further studies are necessary to understand the underlying mechanisms associated with the role of vitamin D in the development and disease severity of SD.

The clinical significance of anti-DFS70 autoantibodies and its correlation with Vitamin D levels

OBJECTIVE

This study aims to investigate the clinical significance of anti-dense fine speckled 70 (DFS70) autoantibodies and its association with systemic autoimmune rheumatic diseases (SARD) related autoimmune markers and Vitamin D levels.

METHODS

The study group consisted of 281 (mean age±SD: 45.31±15.89 years; 88.3% female) anti-DFS70 autoantibody-positive patients. All patients' sera in the study group were tested by ANA HEp-2 indirect immunofluorescent antibody (IIF) and immunoblotting (IB) methods (Euroimmun AG, Lübeck, Germany). Anti-DFS70 antibody-positive patients were divided into two subgroups. Anti-DFS70 antibody-positive patients with SARD were assigned as Group 1 (n=43), anti-DFS70 antibody-positive patients without SARD were assigned as Group 2 (n=238). A control group with anti-DFS70 negative patients with SARD were assigned as Group 3 (n=49, mean age±SD: 49.86±12.08; 79.6% female). The clinical characteristics, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), neutrophil/lymphocyte ratio, thrombocyte/lymphocyte ratio (TLR), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and 25-hydroxyvitamin D3 (25OHD3) levels were compared between three groups.

RESULTS

The majority (61.9%) of anti-DFS70 antibody positive patients had no specific diagnosis. Other systemic diseases were detected as allergic diseases (10.0%), hematological abnormalities (5.0%), thyroid diseases (3.6%), gastrointestinal system diseases (1.8%), malignancies (1.4%), and infections (1.1%). ESR, CRP levels, and TLR were lower in Group 2 than Groups 1 and 3 (p<0.05). RF and anti-CCP positivity rates were lower in Group 2 when compared with Groups 1 and 3 (p<0.05). 25OHD3 levels did not differ between three groups (p=0.103).

CONCLUSION

We observed that anti-DFS70 autoantibody may be associated with organ-specific autoimmune diseases, allergic diseases, and hematological disorders. Therefore, it is essential to evaluate these pathologies in patients positive for anti-DFS70 antibodies.

Association of High Calcitriol Serum Levels and Its Hydroxylation Efficiency Ratio with Disease Risk in SLE Patients with Vitamin D Deficiency

Vitamin D (calcidiol) deficiency in systemic lupus erythematosus (SLE) is more frequent than in healthy subjects (HS); it is associated with clinical activity and damage in SLE. Although calcidiol is considered the best indicator of the vitamin D serum status, its deficiency could not reflect its hydroxylation efficiency ratio and calcitriol serum status. This study was aimed at assessing the association of calcidiol and calcitriol serum levels and its hydroxylation efficiency ratio with the risk to clinical and renal disease activities in SLE patients. A cross-sectional study was conducted in 308 SLE and HS women; calcidiol and calcitriol serum levels were evaluated by immunoassays. SLE patients showed lower calcidiol serum levels vs. HS (21.2 vs. 24.2 ng/mL; p < 0.001). Active SLE patients presented higher calcidiol/calcitriol ratio scores vs. inactive SLE patients (2.78 vs. 1.92 pg/ng; p = 0.02), and SLE patients with renal disease activity showed a pattern of calcidiol-deficient levels (19.5 vs. 25.3 ng/mL; p < 0.04) with higher calcitriol levels (47 pg/mL vs. 41.5 pg/mL; p = 0.02) and calcidiol/calcitriol ratio scores (2.13 vs. 1.54 pg/ng; p < 0.02) compared to SLE patients without renal disease activity. Calcidiol levels were negatively correlated with calcitriol levels (r = −0.26; p = 0.001) and urine proteins (mg/dL) (r = −0.39; p < 0.01). Regarding calcitriol levels, it was positively correlated with the blood lymphocyte count (r = 0.30; p < 0.001) and negatively correlated with the glomerular filtration rate (r = −0.28; p = 0.001). Moreover, the calcitriol/calcidiol ratio was positively correlated with urine proteins (r = 0.38; p < 0.01). The calcidiol deficiency (OR = 2.27; 95% CI = 1.15-4.49; p < 0.01), high calcitriol levels (T3^rd, OR = 4.19, 95% CI = 2.23-7.90; p < 0.001), and a high calcitriol/calcidiol ratio score (T3^rd, OR = 5.93, 95% CI: 3.08-11.5; p < 0.001) were associated with the risk for SLE. In conclusion, a pattern of calcidiol deficiency with high calcitriol serum levels and a high vitamin D hydroxylation efficiency ratio was associated with disease risk in SLE patients.

Vitamin D Deficiency, Osteoporosis and Effect on Autoimmune Diseases and Hematopoiesis: A Review

Vitamin D (VD) is essential for bone homeostasis, but it is also involved in pleiotropic effects on various organs and tissues. In adults, VD deficiency can cause or exacerbate osteoporosis and induce osteomalacia. However, every tissue and cell in the body has a VD receptor, including the brain, heart, stomach, pancreas, skin, gonads, and immune cells, and a deficiency may modify the function of these organs. Thus, the wide-ranging actions of VD help to explain why a reduction in VD amount has been correlated with numerous chronic diseases. In fact, VD deficiency increases the risk of osteoporosis and several other diseases and complications characterized by impaired bone metabolisms, such as autoimmune diseases, inflammatory bowel diseases, allergy, endocrinological diseases, hematological malignancies, and bone marrow transplantation. This review aims to investigate the link between VD deficiency, osteoporosis, and its concomitant diseases. Further epidemiological and mechanistic studies are necessary in order to ascertain the real role of hypovitaminosis in causing the reported diseases; however, adequate vitamin supplementation and restoration of metabolic normality could be useful for better management of these pathologies.

Assessing vitamin D levels in an anti-DFS70 positive population: New insights emerging

Background: Anti-dense fine speckled 70 (DFS70) autoantibodies have more often been described in apparently healthy individuals than in patients with systemic autoimmune rheumatic diseases (SARD). The aim of this study was to explore the link between anti-DFS70 autoantibodies and vitamin D (25(OH)D) levels in an Italian adult cohort.Methods: Serum samples from 34 (five males and 29 females) anti-DFS70 positive patients (index cases), 34 ANA-negative healthy controls, 34 ANA-positive anti-DFS70 negative SLE patients, both groups age- and gender-matched with the index cases, 23 ANA-positive anti-DFS70 negative healthy blood donors and six female SARD patients showing mixed DFS positive pattern were collected and tested for 25(OH)D levels. Relevant demographics and lifestyle practices, body mass index (BMI), comorbidities, and use of medication were recorded for patients and healthy controls.Results: Mean serum levels of 25(OH)D were significantly higher in anti-DFS70 positive subjects (mean ± SD: 22.1 ± 9.8 ng/ml) than in ANA-negative healthy controls (mean ± SD: 17.3 ± 6.7 ng/ml; p = .03), ANA-positive healthy controls (mean ± SD: 15.2 ± 6.8 ng/ml; p = .01), SLE patients (16.6 ± 11.0 ng/ml; p = .01) and in patients with SARD (15.0 ± 5.6 ng/ml; p = .01). No statistically relevant differences in BMI, clinical, or demographic parameters were found.Conclusions: Our findings showed higher levels of vitamin D in anti-DFS70 positive subjects than in the controls, which is compatible with the hypothesis of the "benign" nature of anti-DFS70 antibodies.

Vitamin D Levels and Associations in Indian Patients with Primary Sjögren's Syndrome

Introduction

Vitamin D is a steroid hormone belonging to the class of secosteroids with myriad immune functions and has been implicated in aetiopathogenesis of various autoimmune diseases. Although, there have been various studies showing the association of vitamin D in rheumatoid arthritis and lupus in different populations, there have been limited studies on vitamin D and primary Sjögren's Syndrome (pSS). There are no studies on association of vitamin D and pSS from any tropical country including Indian subcontinent.

Aim

The purpose of the study was to look for any association between 25-hydroxyvitamin D (25(OH)D) levels and disease manifestations in Indian patients with pSS.

Materials and Methods

This is a retrospective cross-sectional study done at a tertiary teaching hospital in southern India in 235 patients with pSS. Patients satisfying the American European Consensus Group (AECG) or American College of Rheumatology (ACR) 2012 for pSS between 2008 and 2015 were included if baseline 25(OH)D levels using electrochemiluminescence were available in hospital's laboratory record, 25(OH)D <20 ng/ml,20-30 ng/ml and >30 ng/ml was defined as deficiency, insufficiency and normal, respectively. Clinical laboratory data and disease activity scoring by EULAR Sjögren's syndrome disease activity index (ESSDAI) were retrieved retrospectively. Latitude corresponding to residence of each patient and the season of performing the assay were recorded. Chi-square statistics was done to find associations between categorized 25(OH)D and outcomes and was reported as odds ratio(95% confidence interval).

Results

Mean 25(OH)D for 235 patients with pSS was 19.98(12.55)ng/ml. A vitamin D deficiency, insufficiency and sufficiency was seen in 141(60%), 60(25.5%) and 34.0(14.5%), respectively. No association was noted between latitude or season of performing assay and the levels. pSS with 25(OH)D ≤30ng/ml had more than two fold risk of higher grading on lip biopsy as well as Rheumatoid Factor (RF) positivity. However, low 25(OH)D seemed to be associated with lower ESSDAI and less pulmonary involvement.

Conclusion

Prevalence of 25(OH)D deficiency in Indian patients with pSS was comparable to that of general Indian population. Low 25(OH)D level ≤30ng/ml was associated with higher odds for RF positivity and positive grading on lip biopsy. Surprisingly, low 25(OH)D was associated with lower ESSDAI score.

Seasonality and autoimmune diseases: The contribution of the four seasons to the mosaic of autoimmunity

Autoimmune diseases (ADs) are a heterogeneous groups of diseases that occur as a results of loss of tolerance to self antigens. While the etiopathogeneis remain obscure, different environmental factors were suggested to have a role in the development of autoimmunity, including infections, low vitamin D levels, UV radiation, and melatonin. Interestingly, such factors possess seasonal variation patterns that could influence disease development, severity and progression. Vitamin D levels which reach a nadir during late winter and early spring is correlated with increased disease activity, clinical severity as well as relapse rates in several disease entities including multiple sclerosis (MS), non-cutaneous flares of systemic lupus erythematosus (SLE), psoriasis, and rheumatoid arthritis (RA). Additionally, immunomodulatory actions of melatonin secretion ameliorate the severity of several ADs including MS and SLE. Melatonin levels are lowest during spring, a finding that correlates with the highest exacerbation rates of MS. Further, melatonin is postulated to be involved in the etiopathogenesis of inflammatory bowel diseases (IBD) through it influence on adhesion molecule and therefore transcription factor expression. Moreover, infections can mount to ADs through pro-inflammatory cytokine release and human antigen mimicry. Seasonal patterns of infectious diseases are correlated with the onset and exacerbation of ADs. During the winter, increased incidence of Epstein-Barr virus (EBV) infectious are associated with MS and SLE flares/onset respectively. In addition, higher Rotavirus infections during the winter precedes type 1 diabetes mellitus onset (T1DM). Moreover, Escherichia coli (E. coli) infection prior to primary biliary cirrhosis (PBC) and T1DM disease onset subsequent to Coxachievirus infections are seen to occur during late summer, a finding that correlate with infectious agents' pattern of seasonality. In this review, the effects of seasonality on the onset, relapses and activity of various ADs were discussed. Consideration of seasonal variation patterns of ADs can possibly provide clues to diseases pathogenesis and lead to development of new approaches in treatment and preventative care.

Vitamin D deficiency as a risk factor for the development of autoantibodies in patients with ASIA and silicone breast implants: a cohort study and review of the literature

The development of autoimmunity and/or autoimmune diseases is multifactorial. Vitamin D is one of the factors that might play a role. We postulated that both the presence of adjuvants and insufficient levels of vitamin D may result in the development of autoimmunity in patients with autoimmune/inflammatory syndrome induced by adjuvants (ASIA) in relation to silicone implant incompatibility. We measured vitamin D levels in 135 patients with ASIA in relation to silicone implant incompatibility and related findings to the presence of autoantibodies that are commonly used to diagnose systemic autoimmune diseases. Furthermore, we systematically reviewed the literature regarding vitamin D deficiency as a risk factor for the development of autoantibodies. Vitamin D measurements were available for analysis in 131 of 135 patients with ASIA in relation to SIIS. Twenty-three patients (18%) tested positive for autoantibodies, from which 18 patients (78%) had either a vitamin D deficiency or insufficiency (median vitamin D level 60.5 mmol/L), whereas five patients (22%) had sufficient vitamin D levels. The risk to develop autoantibodies was significantly increased in vitamin D deficient and/or insufficient patients [RR 3.14; 95% CI, 1.24–7.95; p = 0.009]. Reviewed literature suggested an association between vitamin D levels and the presence and/or titer levels of autoantibodies in different autoimmune diseases. From our current study and from our review of the literature, we conclude that vitamin D deficiency is related to the presence of autoantibodies. Whether vitamin D supplementation results in a decrease of autoimmunity needs to be studied prospectively.

Vitamin D and Its Relevance in the Etiopathogenesis of Oral Cavity Diseases

Vitamin D belongs to a group of fat-soluble secosteroids which assume many roles in the human organism. In humans the most important forms are vitamin D3 and vitamin D2. Their primary function is the regulation of the calcium and phosphorus balance, which promote the growth of healthy bony tissue. Studies over the past few years have revealed a much wider role of vitamin D involving the aging processes, carcinogenesis, the carbohydrate balance as well as the effects on the course of various infections. In this paper we discuss the basic functions of vitamin D in the human body and the mechanisms of its activity and we summarize recent reports on the impact of vitamin D on the oral cavity with a special emphasis on autoimmunologic diseases, including: recurrent aphthous stomatitis, Behçet syndrome and Sjögren syndrome.

Recommendations for the treatment of Sjögren's syndrome

The recommendations proposed by the Sjögren's Syndrome Committee of the Brazilian Society of Rheumatology for the treatment of Sjögren's syndrome were based on a systematic review of literature in Medline (PubMed) and the Cochrane databases until October 2014 and on expert opinion in the absence of studies on the subject. 131 items classified according to Oxford & Grade were included. These recommendations were developed in order to guide the appropriate management and facilitate the access to treatment for those patients with an appropriate indication, considering the Brazilian socioeconomic context and pharmacological agents available in this country.

The association of vitamin D deficiency with tear break-up time and Schirmer testing in non-Sjögren dry eye

PURPOSE

To investigate the effect of vitamin D deficiency on tear break-up time (TBUT) and Schirmer test scores and to assess their relationship in non-Sjögren dry-eye patients.

METHODS

Thirty-four patients with serum vitamin D deficiency and 21 control subjects with normal vitamin D levels were included in this study. The TBUT and Schirmer-1 test without topical anesthesia were performed to all patients.

RESULTS

The mean TBUT were 5.18±2.15 and 7.36±3.10 s and Schirmer scores were 12.18±6.44 and 18.57±8.99 mm in the study and control groups, respectively. TBUT scores and Schirmer-1 results of the study group were significantly lower than the control group (P=0.01 and 0.007, respectively). The mean vitamin D levels were 11.50±1.8 ng/ml in the study group and 32.8±8.72 ng/ml in control group (P=0.001). Dry-eye symptoms were detected in all patients in the study group and 15% of the patients in the control group.

CONCLUSIONS

We demonstrated that vitamin D deficiency decreases the TBUT and Schirmer test values and may be associated with dry-eye symptoms in non-Sjögren syndrome.

Vitamin D in systemic and organ-specific autoimmune diseases

Lately, vitamin D has been linked with metabolic and immunological processes, which established its role as an essential component of human health preservation. Vitamin D has been defined as natural immune modulators, and upon activation of its receptors (VDRs), it regulates calcium metabolism, cellular growth, proliferation and apoptosis, and other immunological functions. Epidemiological data underline a strong correlation between poor vitamin D status and higher risk for chronic inflammatory illnesses of various etiologies, including autoimmune diseases. Epidemiological, genetic, and basic studies indicated a potential role of vitamin D in the pathogenesis of certain systemic and organ-specific autoimmune diseases. These studies demonstrate correlation between low vitamin D and prevalence of diseases. In addition, VDRs' polymorphisms observed in some of these autoimmune diseases may further support a plausible pathogenic link. Notably, for some autoimmune disease, no correlation with vitamin D levels could be confirmed. Thus, in the current review we present the body of evidence regarding the plausible roles of vitamin D and VDR's polymorphism in the pathogenesis of autoimmunity. We summarize the data regarding systemic (i.e., systemic lupus erythematosus, rheumatoid arthritis, etc.) and organ-specific (i.e., multiple sclerosis, diabetes mellitus, primary biliary cirrhosis, etc.) autoimmune diseases, in which low level of vitamin D was found comparing to healthy subjects. In addition, we discuss the correlations between vitamin D levels and clinical manifestations and/or activity of diseases. In this context, we address the rational for vitamin D supplementation in patients suffering from autoimmune diseases. Further studies addressing the mechanisms by which vitamin D affects autoimmunity and the proper supplementation required are needed.

Hypokalemic paralysis as a presenting manifestation of primary Sjögren's syndrome accompanied by vitamin D deficiency

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by progressive lymphocyte infiltration of the exocrine glands. Overt or latent renal tubular acidosis (RTA) is a common extraglandular manifestation of pSS.Vitamin D deficiency is associated with autoimmune disorders; however, the potential correlation between pSS and vitamin D deficiency is rarely discussed. The current patient presented with distal RTA, hypocalcemia, and hypophosphatemia that were found to be secondary to both vitamin D deficiency and pSS. In patients diagnosed with both distal RTA and vitamin D deficiency, clinicians should consider autoimmune diseases such as pSS, as a possible underlying etiology.

Low levels of vitamin-D are associated with neuropathy and lymphoma among patients with Sjögren's syndrome

BACKGROUND/PURPOSE

Primary Sjögren's syndrome (SS) is a chronic autoimmune disease primarily involving the exocrine glands. The clinical picture of SS ranges from exocrinopathy to systemic disease affecting the lung, kidney, liver, skin, musculockeletal and nervous systems. The morbidity of SS is mainly determined by extraglandular disease and increased prevalence of lymphoma. Environmental and hormonal factors, such as vitamin-D may play a role in the pathogenic process and disease expression. Thus, we aimed to evaluate levels of vitamin-D and their association with manifestations of SS.

METHODS

Vitamin-D levels were determined in 176 primary SS patients and 163 matched healthy volunteers utilizing the LIAISON chemiluminescent immunoassays (DiaSorin-Italy). A correlation between vitamin-D levels and clinical and serological manifestations of SS was performed.

RESULTS

Mean vitamin-D levels were comparable between SS patients and control 21.2 ± 9.4 ng/ml and 22.4 ± 10 ng/ml, respectively. Peripheral neuropathy was diagnosed in 23% of SS patients and associated with lower vitamin-D levels (18.6 ± 5.5 ng/ml vs. 22.6±8 ng/ml (p = 0.04)). Lymphoma was diagnosed in 4.3% of SS patients, who had lower levels of vitamin-D (13.2 ± 6.25 ng/ml), compared to SS patients without lymphoma (22 ± 8 ng/ml), (p = 0.03). Other clinical and serological manifestations did not correlate with vitamin-D status.

CONCLUSIONS

In this study, low levels of vitamin-D correlated with the presence of peripheral neuropathy and lymphoma among SS patients. The link between vitamin-D and neuropathy or lymphoma was reported in other conditions, and may support a role for vitamin-D in the pathogenesis of these processes. Plausible beneficial effect for vitamin-D supplementation may thus be suggested.

Vitamin D deficiency and connective tissue disease

Recently, the evidence linking vitamin D status as a potential environmental factor affecting autoimmune disease prevalence continues to accumulate. Beyond that the traditional known metabolic activities, vitamin D has been shown to modulate the immune system and has anti-inflammatory properties. The immune-regulatory role of vitamin D affects both the innate and adaptive immune responses contributing to the immune-tolerance of self-structures. Vitamin D deficiency skews the immunologic response towards loss of tolerance. Serum levels of vitamin D have been found to be significantly lower in several autoimmune or immune-mediated diseases than in the healthy population. Experimental animal models and clinical studies show that 1,25-dihydroxyvitamin D3 or vitamin D receptor (VDR) agonists can either prevent or suppress symptoms of type 1 diabetes, experimental autoimmune encephalomyelitis, rheumatoid arthritis, systemic lupus erthyematosus and inflammatory bowel disease. The heading aims at reviewing the complex immune-regulatory role of vitamin D from the cellular and humoral level through animal models of autoimmune rheumatic diseases and representing the known contribution of vitamin D in the pathogenesis of connective tissue diseases. Increased vitamin D intakes might reduce the incidence and severity of autoimmune disorders besides reducing the rate of osteoporotic bone fracture.

Different proteomic protein patterns in saliva of Sjögren's syndrome patients

OBJECTIVE

To investigate the salivary protein profile in patients with Sjögren's syndrome (SS), and healthy control subjects.

MATERIALS AND METHODS

Unstimulated whole saliva samples were collected from 16 age-matched females; eight healthy subjects and eight patients diagnosed with SS (six primary SS, one incomplete SS and one primary SS associated with B cell lymphoma). Proteins were extracted and separated individually by 2D sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Selected protein spots of interest were analysed by electrospray ionization--tandem mass spectrometry. Obtained data were searched against the Swiss-Prot and NCBI non-redundant protein databases using Mascot software.

RESULTS

Two groups of patterns of protein expression were observed in the eight SS patients: a major group (six patients) with significant expression differences from the healthy subjects and the second group (two patients) with a pattern similar to the eight healthy subjects.

CONCLUSION

In this preliminary study, protein expression differences were found between SS patients and healthy subjects. Individual analysis of SS patients exhibited two patterns of protein expression with no direct relation to the clinical, serological or histological severity of disease. This study emphasizes the difficulty of the present proteomic knowledge to diagnose and monitor the sequel of SS development.

Upregulation of lymphocyte apoptosis as a strategy for preventing and treating autoimmune disorders: a role for whole-food vegan diets, fish oil and dopamine agonists

Induced apoptosis of autoreactive T-lymphocyte precursors in the thymus is crucial for the prevention of autoimmune disorders. IGF-I and prolactin, which are lymphocyte growth factors, may have the potential to suppress apoptosis in thymocytes and thus encourage autoimmunity; conversely, dietary fish oil rich in omega-3 fats appears to upregulate apoptosis in lymphocytes. Since whole-food vegan diets may downregulate systemic IGF-I activity, it is proposed that such a diet, in conjunction with fish oil supplementation and treatment with dopamine agonists capable of suppressing prolactin secretion, may have utility for treating and preventing autoimmune disorders. This prediction is consistent with the extreme rarity of autoimmune disorders among sub-Saharan black Africans as long as they followed their traditional quasi-vegan lifestyles, and with recent ecologic studies correlating risks for IDDM and for multiple sclerosis mortality with animal product and/or saturated fat consumption. Moreover, there is evidence that vegan or quasi-vegan diets are useful in the management of rheumatoid arthritis, multiple sclerosis, and possibly SLE. The dopamine agonist bromocryptine exerts anti-inflammatory effects in rodent models of autoimmunity, and there is preliminary evidence that this drug may be clinically useful in several human autoimmune diseases; better tolerated D2-specific agonists such as cabergoline may prove to be more practical for use in therapy. The moderate clinical utility of supplemental fish oil in rheumatoid arthritis and certain other autoimmune disorders is documented. It is not unlikely that extra-thymic anti-inflammatory effects contribute importantly to the clinical utility of vegan diets, bromocryptine, and fish oil in autoimmunity. The favorable impact of low latitude or high altitude on autoimmune risk may be mediated by superior vitamin D status, which is associated with decreased secretion of parathyroid hormone; there are theoretical grounds for suspecting that parathyroid hormone may inhibit apoptosis in thymocytes. Androgens appear to up-regulate thymocyte apoptosis, may be largely responsible for the relative protection from autoimmunity enjoyed by men, and merit further evaluation for the management of autoimmunity in women. It will probably prove more practical to prevent autoimmune disorders than to reverse them once established; a whole-food vegan diet, coupled with fish oil and vitamin D supplementation, may represent a practical strategy for achieving this prevention, while concurrently lowering risk for many other life-threatening 'Western' diseases.

Procollagen type I N-terminal propeptide (PINP) as an indicator of type I collagen metabolism: ELISA development, reference interval, and hypovitaminosis D induced hyperparathyroidism

A sandwich enzyme-linked immunosorbent assay (ELISA) for quantification of the N-terminal propeptide of human procollagen type I (PINP) utilizing purified alpha 1-chain specific rabbit antibodies is described. The ELISA measured the content of the alpha 1-chain of PINP independent of the molecular form of the molecule. A parallelism was found between amniotic fluid (calibrator), normal and patient serum, and purified PINP (alpha 1), as well as the high and low molecular weight forms of PINP (alpha 1). The concentration of PINP in the calibrator (second trimester amniotic fluid) was determined to 25 micrograms/mL and the detection limit was 62 pg/mL measured in amniotic fluid, and 41 pg/mL measured in serum. The interassay coefficients of variation were 4.6% (low control) and 5.3% (high control), and the corresponding intraassay parameters were 2.9% and 4.9%. Recovery studies revealed an accuracy between 93% and 105%. The normal range (n = 57) for PINP was 56 ng/mL (median) the 10th and 90th centiles being 30 and 82 ng/mL, respectively. Patients with hyperparathyroidism due to hypovitaminosis D had median serum level of 168 ng/mL with a 10th centile of 44 ng/mL and a 90th centile of 450 ng/mL, these values being significantly different from the normal range (p < 0.001). The PINP-ELISA was superior to commercially available assays for PICP and osteocalcin in separation between healthy controls and patients with osteomalaci.

Vitamin D3 metabolism in patients with rheumatic diseases: low serum levels of 25-hydroxyvitamin D3 in patients with systemic lupus erythematosus

1,25-dihydroxyvitamin D3 (1,25(OH)2 D3) has been shown to modulate lymphocyte activation in vitro. Through binding to specific receptors 1,25-(OH)2 D3 inhibits proliferation, immunoglobulin production and the release of cytokines. Moreover, 1,25-(OH)2 D3 is efficiently produced by activated monocytes. These findings suggest that 1,25-(OH)2 D3 may play a role as a regulator of immunological activation. Consequently, we found it of interest to study the serum levels of the two major metabolites of vitamin D3 in patients with systemic lupus erythematosus (SLE) (n = 21), rheumatoid arthritis (RA) (n = 29) and osteoarthritis (n = 12). In patients with SLE the levels of 25-OH D3 were below those of the healthy controls (p = 0.0008) and OA (p = 0.0168). The levels 1,25-(OH)2 D3 corresponded to normal levels. There were no significant correlations between 25-OH D3 levels and clinical or paraclinical disease manifestations. Further, the phenotypic distribution of Gc-globulin, which binds vitamin D3 metabolites in circulation, was normal. The serum concentrations of 1,25-(OH)2 D3 and 25-OH D3 in patients with RA and OA corresponded to those of the controls. Although the cause of the reduced 25-OH D3 levels in SLE patients is unclear, possible beneficial effects of administration of vitamin D to these patients should be considered.