Calcium and vitamin D in sarcoidosis: how to assess and manage

Kidney manifestations of sarcoidosis

Renal involvement is a clinically relevant organ manifestation of sarcoidosis, leading to increased morbidity and complications. Although the exact incidence remains unknown, renal disease is likely to occur in up to one third of all sarcoidosis patients. Every patient with newly diagnosed sarcoidosis should receive a renal work-up and screening for disrupted calcium metabolism. Amid various forms of glomerulonephritis, granulomatous interstitial nephritis is the most common one, but it rarely leads to renal impairment. Histologically, granulomas can be absent. Nephrocalcinosis and nephrolithiasis are frequent forms when hypercalcaemia or hypercalciuria occur. Drugs used for treatment of systemic sarcoidosis can also cause renal damage. Due to its high heterogeneity, renal sarcoidosis can be difficult to treat. Glucocorticoids and various immunosuppressive treatments have been proven to be effective based on case series, but clinical trials are lacking. A treatment guideline for renal sarcoidosis is urgently needed. In this review article, we present an overview of the different forms of renal sarcoidosis and the diagnostic steps to confirm renal involvement; in addition, we provide insights on the management and available treatments. A better understanding regarding the pathogenesis of sarcoidosis is the key for the development of more specific, targeted therapies.

A single-center rheumatology experience of sarcoidosis: observations from 70 patients

BACKGROUND

The aim of this study is to determine the demographic, clinical and laboratory characteristics of the patients who followed up with the diagnosis of sarcoidosis, to investigate the distribution frequency of rheumatological findings and to examine the disease management from the perspective of rheumatology.

METHODS

Patients who were followed up with the diagnosis of sarcoidosis in the rheumatology clinic of Ankara City Hospital between November 2019 and November 2022 were evaluated. Demographic, clinical, radiological, serological, laboratory, and histopathological findings, and rheumatological, systemic, and locomotor system examination findings of the patients were obtained from the medical data registered in the hospital.

RESULTS

A total of seventy sarcoidosis patients (48.98 ± 11.78 years, %75 female) were included in the study. Joint involvement was observed in 64.3% of cases, skin involvement in 48.6% of cases, and ocular involvement in 25.7% of cases. The ankle was the most frequently involved joint, followed by the knee and small joints in the foot. Corticosteroids were the most used therapeutic agent, and pulmonary and joint findings were the most common reasons for starting treatment.

CONCLUSIONS

Sarcoidosis is a disease that mimics many diseases, misdiagnosis and treatment should be avoided with a good and fast differential diagnosis. Clinicians, especially rheumatologists, should remember sarcoidosis more frequently and keep it in mind in the differential diagnosis.

A Rare Case of Extra-Pulmonary Sarcoidosis With Only Initial Presentation of Hypercalcemia

Sarcoidosis is a systemic disorder characterized by the aberrant development of granulomatous inflammation within various organs in the body. In over 90% of cases, sarcoidosis typically manifests initially in the intra-thoracic region, characterized by pulmonary involvement or mediastinal lymphadenopathy. It is rare for sarcoidosis to manifest exclusively as extra-thoracic involvement and even more rarely for hypercalcemia to be the only initial sign. We present a case of a 70-year-old female with hypercalcemia and elevated 1,25-dihydroxyvitamin D3 (1,25(OH)2 D) which raised the suspicion of a granulomatous disease. Granulomatous diseases increase levels of 1,25(OH)2 D via the abnormal expression of 1 alpha-hydroxylase enzyme; therefore, these conditions should be considered in the differential diagnosis when encountered with hypercalcemia. PET-CT showed increased FDG uptake in the reticuloendothelial system. An easily accessible inguinal lymph node biopsy was performed which revealed non-necrotizing granulomatous inflammation. Other causes of non-necrotizing granulomatous diseases, cancer, and lymphoma were ruled out, leading to sarcoidosis being considered as a possible diagnosis. When diagnosing sarcoidosis, other potential causes of granulomatous inflammation need to be ruled out definitively via laboratory findings, imaging, and tissue histopathology before initiation of treatment with steroids. Treatment with glucocorticoids remains the mainstay therapy of 1,25(OH)2 D-mediated hypercalcemia associated with sarcoidosis. The patient was accordingly treated with prednisone which led to the normalization of calcium and 1,25(OH)2 D levels within three weeks. Here, we discuss the clinical features and investigations of extra-pulmonary sarcoidosis for early diagnosis and management.

Vitamin D and Its Analogues: From Differences in Molecular Mechanisms to Potential Benefits of Adapted Use in the Treatment of Alzheimer’s Disease

Lifestyle habits and insufficient sunlight exposure lead to a high prevalence of vitamin D hypovitaminosis, especially in the elderly. Recent studies suggest that in central Europe more than 50% of people over 60 years are not sufficiently supplied with vitamin D. Since vitamin D hypovitaminosis is associated with many diseases, such as Alzheimer’s disease (AD), vitamin D supplementation seems to be particularly useful for this vulnerable age population. Importantly, in addition to vitamin D, several analogues are known and used for different medical purposes. These vitamin D analogues differ not only in their pharmacokinetics and binding affinity to the vitamin D receptor, but also in their potential side effects. Here, we discuss these aspects, especially those of the commonly used vitamin D analogues alfacalcidol, paricalcitol, doxercalciferol, tacalcitol, calcipotriol, and eldecalcitol. In addition to their pleiotropic effects on mechanisms relevant to AD, potential effects of vitamin D analogues on comorbidities common in the context of geriatric diseases are summarized. AD is defined as a complex neurodegenerative disease of the central nervous system and is commonly represented in the elderly population. It is usually caused by extracellular accumulation of amyloidogenic plaques, consisting of amyloid (Aβ) peptides. Furthermore, the formation of intracellular neurofibrillary tangles involving hyperphosphorylated tau proteins contributes to the pathology of AD. In conclusion, this review emphasizes the importance of an adequate vitamin D supply and discusses the specifics of administering various vitamin D analogues compared with vitamin D in geriatric patients, especially those suffering from AD.

Recurrent small bowel obstruction as a rare presentation of undiagnosed sarcoidosis

Sarcoidosis is an immune-mediated inflammatory disorder with unknown aetiology that is marked by non-caseating granulomas in affected organs. Pulmonary sarcoidosis is the most common manifestation, but gastrointestinal involvement, particularly in the small bowel, is exceedingly rare. While symptom-driven treatment guidelines that are steroid based are well established for pulmonary and few extrapulmonary manifestations (ie, cardiac, neurologic, renal), gastrointestinal sarcoidosis treatment is largely extrapolation with optimal management under investigation. Additionally, few works document small bowel obstruction related to small bowel sarcoidosis. We present a case of short-interval recurrent small bowel obstruction in a man in his sixties that revealed newly diagnosed sarcoidosis with suspected small bowel involvement who never underwent steroid therapy. The patient exhibited gastrointestinal symptoms, despite asymptomatic pulmonary disease and a course of prednisone may have reduced his risk of recurrence. We also review suggested gastrointestinal sarcoidosis treatment and surveillance guidelines with focus on the small bowel.

Perspective of sarcoidosis in terms of rheumatology: a single-center rheumatology clinic experience

Sarcoidosis may present with many rheumatological symptoms as well as mimic and/or may occur concomitantly with many other rheumatic diseases. We examined the demographic, clinical and laboratory characteristics of patients diagnosed with sarcoidosis in the rheumatology department. This study planned as retrospective cross-sectional study. Medical records of patients who applied to our rheumatology outpatient clinic due to complain of musculoskeletal problems and then diagnosed sarcoidosis were retrospectively investigated. Joint findings, extrapulmonary involvements, and coexisting rheumatic disease were evaluated. Fifty-six patients (41.21 ± 7.83 years, 75% female) were included. The duration of the disease was 49.61 ± 29.11 months, and the follow-up period was 26.66 ± 13.26 months. All patients had pulmonary system involvement. Arthralgia was present in 91.10% of 56 patients and arthritis in 89.29% of patients. Examining the subtypes of the arthritis findings, mono-arthritis was found in 31/50 (62%) patients, oligo-arthritis in 15/50 (30%) patients, and polyarthritis in 4/50 (8%) patients. A total of 11 (19.60%) patients were diagnosed with uveitis. Excision of the mediastinal LAP was performed in a total of 37 patients (66.1%) and became the most commonly employed method. Considering the treatment distribution of the patients under followed-up, it is seen that non-steroidal anti-inflammatory treatments were used in 15 (26.8%) patients, corticosteroids in a total of 40 (71.4%) patients, methotrexate in a total of 15 patients (26.8%), azathioprine in six (10.7%) patients, hydroxychloroquine in 14 (25%) patients, and infliximab in one (1.8%) patient. As sarcoidosis is a mimicking disease, a good differential diagnosis should be made to avoid misdiagnosis and in order not to be late in diagnosis and treatment. Physicians, especially rheumatologists, should remember sarcoidosis more frequently as the disease may overlap with other rheumatological diseases and may occur with many rheumatological manifestations.

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

Sarcoid Uveitis: An Intriguing Challenger

The purpose of our work is to describe the actual knowledge concerning etiopathogenesis, clinical manifestations, diagnostic procedures, complications and therapy of ocular sarcoidosis (OS). The study is based on a recent literature review and on the experience of our tertiary referral center. Data were retrospectively analyzed from the electronic medical records of 235 patients (461 eyes) suffering from a biopsy-proven ocular sarcoidosis. Middle-aged females presenting bilateral ocular involvement are mainly affected; eye involvement at onset is present in one-third of subjects. Uveitis subtype presentation ranges widely among different studies: panuveitis and multiple chorioretinal granulomas, retinal segmental vasculitis, intermediate uveitis and vitreitis, anterior uveitis with granulomatous mutton-fat keratic precipitates, iris nodules, and synechiae are the main ocular features. The most important complications are cataract, glaucoma, cystoid macular edema (CME), and epiretinal membrane. Therapy is based on the disease localization and the severity of systemic or ocular involvement. Local, intravitreal, or systemic steroids are the mainstay of treatment; refractory or partially responsive disease has to be treated with conventional and biologic immunosuppressants. In conclusion, we summarize the current knowledge and assessment of ophthalmological inflammatory manifestations (mainly uveitis) of OS, which permit an early diagnostic assay and a prompt treatment.

Routine Laboratory Biomarkers As Prognostic Indicators of Cardiac Sarcoidosis Outcomes

Background

Biomarkers to monitor disease activity and predict major adverse cardiac events (MACE) in CS have not been described previously. We aimed to identify biomarkers to predict MACE in cardiac sarcoidosis (CS).

Methods

Patients (N=232) diagnosed with CS were retrospectively enrolled. Biomarkers including angiotensin-converting enzyme (ACE), N-terminal brain natriuretic peptide (NT-proBNP), troponin T, and creatinine levels were evaluated against a primary end point of left ventricular assist device implantation, heart transplantation, or death, and a secondary end point of cardiac hospitalization-free survival.

Results

Troponin T (hazard ratio [HR], 1.06 per 0.01 ng/mL; P=.006), NT-proBNP (HR, 1.31 per 1,000 pg/mL; P<.001), and creatinine (HR, 4.02 per mg/dL; P=.01) were associated with the primary end point, even after adjusting for ejection fraction. NT-proBNP, B-type natriuretic peptide (BNP), creatinine, albumin, and calcium were associated with the secondary end point (P<.05). ACE levels were associated with presence of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging (mean difference, 14.7; P=.03); 1,25 dihydroxyvitamin D (1,25-OHVit-D) was associated with uptake on cardiac ¹⁸F-flurodeoxyglucose position emission tomography (FDG-PET, P=.03).

Conclusions

Troponin T, NT-proBNP, and creatinine predict clinically significant outcomes in CS. ACE levels correlated with LGE on CMR, and 1,25-OHVit-D levels correlated with FDG-PET activity.

Vitamin D Supplementation in Sarcoidosis: A Double-Edged Sword

Sarcoidosis is complicated by disordered vitamin D and calcium metabolism, which has important implications on disease activity and bone health. Although the majority of the patients with sarcoidosis are typically deficient in 25-hydroxyvitamin D, repletion of vitamin D is controversial in light of the hypercalcemia risk. Presently, there are no clear guidelines regarding vitamin D supplementation as a part of osteoporosis prevention in patients with vitamin D deficiency and sarcoidosis. We report a patient with sarcoidosis who presented with severe hypercalcemia following vitamin D supplementation and review the debated role of vitamin D supplementation in vitamin D-deficient sarcoid patients.

The association between vitamin D and uveitis: A comprehensive review

Vitamin D plays an important role in both the innate and adaptive immune systems. We review published data on the relationship between uveitis and vitamin D levels or vitamin D-associated gene polymorphisms. A search of the PubMed and Medline databases was conducted to identify relevant articles concerning vitamin D and uveitis. Sixteen studies were included in this review, and the evidence they present, linking low vitamin D levels with uveitis, is compelling. The uveitic entities shown to be modulated by hypovitaminosis D include, but are not limited to, HLA-B27-associated acute anterior uveitis, Vogt-Koyanagi-Harada (VKH) disease, sarcoidosis-associated uveitis, and juvenile idiopathic arthritis-associated uveitis. Specific polymorphisms of vitamin D family genes were found to correlate with uveitis in ankylosing spondylitis, Behçet's disease, VKH, and HLA B27-positive patients. Further understanding of the role of vitamin D, a known regulator of inflammatory processes, in noninfectious uveitis may advance capabilities in the fields of disease prevention and treatment.

Lower serum 25(OH)D levels associated with higher risk of COVID-19 infection in U.S. Black women

Objective

Limited evidence suggests that higher levels of serum vitamin D (25(OH)D) protect against SARS-CoV-2 virus (COVID-19) infection. Black women commonly experience 25(OH)D insufficiency and are overrepresented among COVID-19 cases. We conducted a prospective analysis of serum 25(OH)D levels in relation to COVID-19 infection among participants in the Black Women’s Health Study.

Methods

Since 1995, the Black Women’s Health Study has followed 59,000 U.S. Black women through biennial mailed or online questionnaires. Over 13,000 study participants provided a blood sample in 2013–2017. 25(OH)D assays were performed in a certified national laboratory shortly after collection of the samples. In 2020, participants who had completed the online version of the 2019 biennial health questionnaire were invited to complete a supplemental online questionnaire assessing their experiences related to the COVID-19 pandemic, including whether they had been tested for COVID-19 infection and the result of the test. We used logistic regression analysis to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association of 25(OH)D level with COVID-19 positivity, adjusting for age, number of people living in the household, neighborhood socioeconomic status, and other potential confounders.

Results

Among 5,081 eligible participants whose blood sample had been assayed for 25(OH)D, 1,974 reported having had a COVID-19 test in 2020. Relative to women with 25(OH)D levels of 30 ng/mL (75 nmol/l) or more, multivariable-adjusted ORs for COVID-19 infection in women with levels of 20–29 ng/mL (50–72.5 nmol/l) and <20 ng/mL (<50 nmol/l) were, respectively, 1.48 (95% CI 0.95–2.30) and 1.69 (95% CI 1.04–2.72) (p trend 0.02).

Conclusion

The present results suggest that U.S. Black women with lower levels of 25(OH)D are at increased risk of infection with COVID-19. Further work is needed to confirm these findings and determine the optimal level of 25(OH)D for a beneficial effect.

The role of vitamin D in sarcoidosis

After the initial description of extrarenal synthesis of 1,25-dihydroxyvitamin D (1,25-(OH)₂D) three decades ago, extensive progress has been made in unraveling the immunomodulatory roles of vitamin D in the pathogenesis of granulomatous disorders, including sarcoidosis. It has been shown that 1,25-(OH)₂D has dual effects on the immune system, including upregulating innate immunity as well as downregulating the autoimmune response. The latter mechanism plays an important role in the pathogenesis and treatment of sarcoidosis. Vitamin D supplementation in patients with sarcoidosis has been hampered owing to concerns about the development of hypercalcemia and hypercalciuria given that extrarenal 1-α hydroxylase is substrate dependent. Recently, a few studies have cast doubt over the mechanisms underlying the development of hypercalcemia in this population. These studies demonstrated an inverse relationship between the level of vitamin D and severity of sarcoidosis. Consequently, clinical interest has been piqued in the use of vitamin D to attenuate the autoimmune response in this disorder. However, the development of hypercalcemia and the attendant detrimental effects are real possibilities. Although the average serum calcium concentration did not change following vitamin D supplementation, in two recent studies, hypercalciuria occurred in one out of 13 and two out of 16 patients. This review is a concise summary of the literature, outlining past work and newer developments in the use of vitamin D in sarcoidosis. We feel that larger-scale placebo-controlled randomized studies are needed in this population. Since the current first-line treatment of sarcoidosis is glucocorticoids, which confer many systemic adverse effects, and steroid-sparing immunosuppressant treatment options carry additional risks of adverse effects, adjunct management with vitamin D in combination with potent anti-osteoporotic medications could minimize the risk of glucocorticoid-induced osteoporosis and modulate the immune system to attenuate disease activity in sarcoidosis.

Screening Sarcoidosis Patients for Occult Disease

As sarcoidosis may involve any organ, sarcoidosis patients should be evaluated for occult disease. Screening for some organ involvement may not be warranted if it is unlikely to cause symptoms, organ dysfunction, or affect clinical outcome. Even organ involvement that affects clinical outcome does not necessarily require screening if early detection fails to change the patient's quality of life or prognosis. On the other hand, early detection of some forms of sarcoidosis may improve outcomes and survival. This manuscript describes the approach to screening sarcoidosis patients for previously undetected disease. Screening for sarcoidosis should commence with a meticulous medical history and physical examination. Many sarcoidosis patients present with physical signs or symptoms of sarcoidosis that have not been recognized as manifestations of the disease. Detection of sarcoidosis in these instances depends on the clinician's familiarity with the varied clinical presentations of sarcoidosis. In addition, sarcoidosis patients may present with symptoms or signs that are not related to specific organ involvement that have been described as parasarcoidosis syndromes. It is conjectured that parasarcoidosis syndromes result from systemic release of inflammatory mediators from the sarcoidosis granuloma. Certain forms of sarcoidosis may cause permanent and serious problems that can be prevented if they are detected early in the course of their disease. These include (1) ocular involvement that may lead to permanent vision impairment; (2) vitamin D dysregulation that may lead to hypercalcemia, nephrolithiasis, and permanent kidney injury; and (3) cardiac sarcoidosis that may lead to a cardiomyopathy, ventricular arrhythmias, heart block, and sudden death. Screening for these forms of organ involvement requires detailed screening approaches.

Postulated Adjuvant Therapeutic Strategies for COVID-19

The number of COVID-19 patients is still growing exponentially worldwide due to the high transmissibility of the SARS-CoV-2 virus. Therapeutic agents currently under investigation are antiviral drugs, vaccines, and other adjuvants that could relieve symptoms or improve the healing process. In this review, twelve therapeutic agents that could play a role in prophylaxis or improvement of the COVID-19-associated symptoms (as add-on substances) are discussed. Agents were identified based on their known pharmacologic mechanism of action in viral and/or nonviral fields and are postulated to interact with one or more of the seven known mechanisms associated with the SARS-CoV-2 virus: (i) regulation of the immune system; (ii) virus entrance in the cell; (iii) virus replication; (iv) hyperinflammation; (v) oxidative stress; (vi) thrombosis; and (vii) endotheliitis. Selected agents were immune transfer factor (oligo- and polypeptides from porcine spleen, ultrafiltered at <10 kDa; Imuno TF®), anti-inflammatory natural blend (Uncaria tomentosa, Endopleura uchi and Haematoccocus pluvialis; Miodesin®), zinc, selenium, ascorbic acid, cholecalciferol, ferulic acid, spirulina, N-acetylcysteine, glucosamine sulfate potassium hydrochloride, trans-resveratrol, and maltodextrin-stabilized orthosilicic acid (SiliciuMax®). This review gives the scientific background on the hypothesis that these therapeutic agents can act in synergy in the prevention and improvement of COVID-19-associated symptoms.

Prevalence, distribution and clinical significance of joints, muscles and bones in sarcoidosis: an 18F-FDG-PET/CT study

OBJECTIVES

In Sarcoidosis joints-muscles-bones (JMBs) localizations are of the least common. ¹⁸F-FDG-PET/CT imaging revolutionized detection of JMBs involvement by adding metabolic activity information and allowing for a comprehensive, whole-body mapping of the disease.

AIM AND METHODS

This study investigated prevalence, distribution, and clinical significance of JMBs sarcoidosis in 195 consecutive patients that underwent ¹⁸F-FDG PET/CT examination.

RESULTS

Joint and bone involvement were encountered in 15% of patients with a mean of the maximum-standardized-uptake-value (SUV_max) of 6.1. Most common location was the axial skeleton. Hypercalciuria was significantly more frequent in patients with osseous involvement (p = 0.003). Muscle activity (SUVmax = 2.4) was encountered in 20% of the patients, most frequently in treatment-naïve (p = 0.02). The muscles of the lower extremities were affected the most. Muscle and bone localization coexist in 50% of the cases. JMBs disease was almost asymptomatic, not related to chronicity but to pulmonary, nodal, and systemic disease. Long-term follow-up and treatment response of affected patients confirmed sarcoidosis.

CONCLUSION

¹⁸F-FDG-PET/CT revealed JMBs localizations and coexistence with other organ sites supporting the concept that sarcoidosis is a systemic disease. By allowing an integrative interpretation of multi-organ involvement in the context of a pattern highly suggestive of sarcoidosis, it strongly keeps-off the diagnosis of malignancy.

Sarcoidosis and calcium homeostasis disturbances-Do we know where we stand?

The majority of cases involving hypercalcemia in the setting of sarcoidosis are explained by the overproduction of calcitriol by activated macrophages. Vitamin D takes part in the regulation of granuloma formation. However, using vitamin D metabolites to assess the activity of the disease is still problematic, and its usefulness is disputable. In some cases, though, a calcium metabolism disorder could be a valuable tool (i.e. as a marker of extrathoracic sarcoidosis). Although sarcoidosis does not cause a decrease in bone mineral density, increased incidence of vertebral deformities is noted. Despite increasing knowledge about calcium homeostasis disorders in patients with sarcoidosis, there is still a need for clear guidelines regarding calcium and vitamin D supplementation in these patients.

A disease with many faces

Can you diagnose this man with progressively worsening shortness of breath, mucous productive cough, weight loss, fatigue and a history of suspected pulmonary tuberculosis? http://bit.ly/2VUdnTr.

DNA Methylation Changes in Lung Immune Cells Are Associated with Granulomatous Lung Disease

Epigenetic marks are likely to explain variability of response to antigen in granulomatous lung disease. The objective of this study was to identify DNA methylation and gene expression changes associated with chronic beryllium disease (CBD) and sarcoidosis in lung cells obtained by BAL. BAL cells from CBD (n = 8), beryllium-sensitized (n = 8), sarcoidosis (n = 8), and additional progressive sarcoidosis (n = 9) and remitting (n = 15) sarcoidosis were profiled on the Illumina 450k methylation and Affymetrix/Agilent gene expression microarrays. Statistical analyses were performed to identify DNA methylation and gene expression changes associated with CBD, sarcoidosis, and disease progression in sarcoidosis. DNA methylation array findings were validated by pyrosequencing. We identified 52,860 significant (P < 0.005 and q < 0.05) CpGs associated with CBD; 2,726 CpGs near 1,944 unique genes have greater than 25% methylation change. A total of 69% of differentially methylated genes are significantly (q < 0.05) differentially expressed in CBD, with many canonical inverse relationships of methylation and expression in genes critical to T-helper cell type 1 differentiation, chemokines and their receptors, and other genes involved in immunity. Testing of these CBD-associated CpGs in sarcoidosis reveals that methylation changes only approach significance, but are methylated in the same direction, suggesting similarities between the two diseases with more heterogeneity in sarcoidosis that limits power with the current sample size. Analysis of progressive versus remitting sarcoidosis identified 15,215 CpGs (P < 0.005 and q < 0.05), but only 801 of them have greater than 5% methylation change, demonstrating that DNA methylation marks of disease progression changes are more subtle. Our study highlights the significance of epigenetic marks in lung immune response in granulomatous lung disease.

Hypercalcaemia secondary to disseminated Mycobacterium abscessus and Mycobacterium fortuitum

The incidence and prevalence of nontuberculous mycobacteria (NTM) infection is on the rise with many cases still going unreported. Given the vague and nonspecific clinical features of NTM infections, it is often missed or mistaken for Mycobacterium tuberculosis. The presumption that NTM infections are benign and do not contribute to morbidity no longer holds true. NTM infections need to be considered in patients with disseminated multisystem disease and in those not responding to standard M. tuberculosis treatment. As NTM infection is associated with granuloma formation, it can result in hypercalcaemia. Interestingly, there is evidence that there may be other mechanisms in play contributing to hypercalcaemia besides the increased calcitriol levels.

Genes and metabolic pathway of sarcoidosis: identification of key players and risk modifiers

INTRODUCTION

Sarcoidosis is a rare multisystem granulomatous disease with unknown etiology. The interplay of vitamin D deficiency and genetic polymorphisms in genes coding for the proteins relevant for metabolism of vitamin D is an important, but unexplored area. The aim of this study was to investigate the association between single nucleotide polymorphisms (SNPs) in CYP2R1 (rs10741657), CYP27B1 (rs10877012), DBP (rs7041; rs4588), and VDR (rs2228570) genes and sarcoidosis, as well as the association between these SNPs and 25(OH)D levels in sarcoidosis patients.

MATERIAL AND METHODS

For that purpose we genotyped 86 sarcoidosis patients and 50 healthy controls using the PCR-RFLP method.

RESULTS

Subjects carrying the CC genotype of CYP27B1 rs10877012 have 10 times lower odds of suffering from sarcoidosis. Moreover, DBP rs4588 AA genotype was shown to be a susceptibility factor, where carriers of this genotype had eight times higher odds for developing sarcoidosis. In addition, the A allele of the DBP gene (rs4588) was associated with lower levels of 25(OH)D in sarcoidosis patients.

CONCLUSIONS

These results suggest that patients with vitamin D deficiency should be regularly tested for genetic modifiers that are related to sarcoidosis in order to prevent development of serious forms of sarcoidosis.

Sarcoidosis

Sarcoidosis is an inflammatory disorder of unknown cause that is characterized by granuloma formation in affected organs, most often in the lungs. Patients frequently suffer from cough, shortness of breath, chest pain and pronounced fatigue and are at risk of developing lung fibrosis or irreversible damage to other organs. The disease develops in genetically predisposed individuals with exposure to an as-yet unknown antigen. Genetic factors affect not only the risk of developing sarcoidosis but also the disease course, which is highly variable and difficult to predict. The typical T cell accumulation, local T cell immune response and granuloma formation in the lungs indicate that the inflammatory response in sarcoidosis is induced by specific antigens, possibly including self-antigens, which is consistent with an autoimmune involvement. Diagnosis can be challenging for clinicians because of the potential for almost any organ to be affected. As the aetiology of sarcoidosis is unknown, no specific treatment and no pathognomic markers exist. Thus, improved biomarkers to determine disease activity and to identify patients at risk of developing fibrosis are needed. Corticosteroids still constitute the first-line treatment, but new treatment strategies, including those targeting quality-of-life issues, are being evaluated and should yield appropriate, personalized and more effective treatments.

Concomitant sarcoidosis and papillary thyroid cancer with severe hypercalcaemia as the main symptom

A 65-year-old Caucasian man was admitted to our hospital due to incidental finding of plasma ionised calcium=1.83 mmol/L. During the previous months, he had felt more tired and had experienced an unintended weight loss of 6-8 kg. A CT scan revealed an inhomogeneous thyroid gland and enlarged lymph nodes along the cervical vessels and in the mediastinum. The patient underwent total thyroidectomy and, at the same time, two lymph nodes were removed. Histological examination of the thyroid gland revealed papillary thyroid carcinoma (PTC), T1aN0M0, and histological examination of the lymph nodes showed non-caseating granulomatous inflammation. After further investigation, a diagnosis of sarcoidosis (SA) was made.Coexistence of SA and PTC may yield a diagnostic challenge as both diseases might involve the lymph nodes of the neck. Furthermore, the case illustrates the importance of close follow-up of even moderate hypercalcaemia, since it may evolve into a hypercalcaemic crisis.

Vitamin D status in sarcoidosis: a cross-sectional study

Background: Hypercalcemia, a common feature in sarcoidosis, is due to the excessive production of active Vitamin D metabolite, 1,25(OH)₂D. Levels of 25(OH) Vitamin D however may not be appropriate. Objectives: To assess Vitamin D status and its clinical associations in sarcoidosis patients compared to a general respiratory diseases out-patient clinic population, serving as controls. Methods: 64 sarcoidosis cases and 53 control cases with other than sarcoidosis respiratory diseases, matched for age and sex were included in the study. Serum 25(OH)D, 1,25(OH)₂D, calcium, angiotensin converting enzyme (ACE) were measured. 25(OH) Vitamin D was described as deficient when <20 ng/ml and insufficient when <30 ng/ml. Clinical parameters were recorded for sarcoidosis cases. Results: Overall 41/64 sarcoidosis cases (64%) had low 25(OH) D, 7/64 (11%) had high 1,25(OH)₂D and 2/64 had hypercalcaemia (3%). Sarcoidosis subjects likely exhibited deficient (39%) or normal 25(OH)D levels (36%) in comparison to controls (p=0.018). 25(OH) Vitamin D deficiency in sarcoidosis was associated with race and radiological stage I disease, with regression analysis identifying African-American race as the only significant risk factor (p=0.03). An inverse correlation between ACE and 25(OH)D levels was found (p=0.052). 1,25(OH)₂D was significantly elevated in sarcoidosis compared to controls. Among sarcoidosis patients, those with insufficient 25(OH)D levels exhibited higher calcium levels in serum. Conclusions: 25(OH) Vitamin D deficiency is prevalent in sarcoidosis, particularly in African-Americans and likely those with active disease. However, concomitant 1,25(OH)₂D elevation and associated hypercalcaemia make Vitamin D supplementation dangerous in sarcoidosis. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 154-159).

Repository corticotropin injection (H.P. Acthar gel) for the treatment of sarcoidosis-induced hypercalciuria and vitamin D dysregulation: a pilot, open label study

Background: Vitamin D dysregulation may occur in sarcoidosis patients and result in hypercalciuria, hypercalcemia, nephrolithiasis, and renal impairment. We performed an open label pilot study of highly purified (H.P.) Acthar® Gel (repository corticotropin injection) (RCI) on patients with sarcoidosis-induced vitamin D dysregulation and hypercalciuria. Methods: Nine patients with sarcoidosis-induced vitamin D dysregulation and hypercalciuria on stable maintenance anti-sarcoidosis therapy received 80 units of RCI subcutaneously twice weekly for 12 weeks. 24-hour urinary calcium excretion was measured at baseline and at 12 weeks. Other parameters measured over 16 weeks (including 4 weeks post the last RCI dose) included the following serum values: calcium, 25-OH vitamin D, 1,25- diOH vitamin D and serum parathyroid hormone (PTH). In addition, the Sarcoidosis Health Questionnaire (SHQ) and Short Form-36 (SF-36) as well as a urinary symptom score were measured in all subjects. Results: There was no significant change in the 24-hour urinary calcium excretion over 12 weeks of the study. However, there was evidence that RCI improved sarcoidosis-induced vitamin D dysregulation in that the serum 1,25- diOH vitamin D level significantly declined over 12 weeks. There was also improvement in most of the domains of the quality of life measures, although only a few of them reached statistical significance. There was also a trend toward improvement in urinary symptoms over the study period. The was evidence of the development corticosteroid side effects in the cohort, in that weight significantly increased over the study period. Conclusions: In this small pilot open label trial, 12 weeks of RCI did not significantly improve sarcoidosis-induced hypercalciuria. However, some statistically significant changes in serum vitamin D and PTH levels were demonstrated that were consistent with some amelioration of sarcoidosis-induced vitamin D dysregulation. Several corticosteroid-related side effects were demonstrated in this cohort. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 192-197).

Association Between Vitamin D Deficiencies in Sarcoidosis with Disease Activity, Course of Disease and Stages of Lung Involvements

BACKGROUND

Despite negative association between 25-hydroxy vitamin D and incidence of many chronic respiratory diseases, this feature was not well studied in sarcoidosis. Current study investigated the association between 25-hydroxy vitamin D deficiency with sarcoidosis chronicity, disease activity, extra-pulmonary skin manifestations, urine calcium level and pulmonary function status in Iranian sarcoidosis patients. Results of this study along with future studies, will supply more effective programs for sarcoidosis treatment.

METHODS

Eighty sarcoidosis patients in two groups of insufficient serum level and sufficient serum level of 25-hydroxy vitamin D were studied. Course of sarcoidosis was defined as acute and chronic sarcoidosis. Pulmonary function test (PFT) was assessed by spirometry. Skin involvements were defined as biopsy proven skin sarcoidosis. 24-hour urine calcium level was used to specify the disease activity. Stages of lung involvements were obtained by CT-scan and chest X-ray. The statistical analyses were evaluated using Statistical Package for the Social Sciences.

RESULTS

A significant negative correlation was obtained between vitamin D deficiency in sarcoidosis patients and disease chronic course and stages two to four of lung involvements. Considering other parameters of the disease and vitamin D deficiency, no significant correlation was detected.

CONCLUSIONS

In conclusion, results of the current study implies in the role of vitamin 25(OH)D deficiencies in predicting the course of chronic sarcoidosis. Furthermore, it was concluded that vitamin 25(OH)D deficiency can direct pulmonary sarcoidosis toward stage 2-4 of lung involvements.

Biomarkers in sarcoidosis

INTRODUCTION

Numerous biomarkers have been evaluated for the diagnosis, assessment of disease activity, prognosis, and response to treatment in sarcoidosis. In this report, we discuss the clinical and research utility of several biomarkers used to evaluate sarcoidosis. Areas covered: The sarcoidosis biomarkers discussed include serologic tests, imaging studies, identification of inflammatory cells and genetic analyses. Literature was obtained from medical databases including PubMed and Web of Science. Expert commentary: Most of the biomarkers examined in sarcoidosis are not adequately specific or sensitive to be used in isolation to make clinical decisions. However, several sarcoidosis biomarkers have an important role in the clinical management of sarcoidosis when they are coupled with clinical data including the results of other biomarkers.

Bone density is normal and does not change over 2 years in sarcoidosis

SUMMARY

Small studies have previously suggested that sarcoidosis may be associated with low bone mineral density. In this observational study of 64 patients with sarcoidosis, bone mineral density was within the normal range at baseline, and there was no evidence of accelerated bone loss over 1-2 years.

INTRODUCTION

Several small studies have suggested that sarcoidosis may be associated with low bone mineral density (BMD).

METHODS

We undertook a cross-sectional study of BMD in 64 patients with sarcoidosis. Of these, 27 with 25-hydroxyvitamin D<50 nmol/L entered a 1-year intervention study of vitamin D supplements, and 37 entered a 2-year longitudinal study of BMD, with the primary endpoint of the change in lumbar spine BMD.

RESULTS

The mean age of participants was 58 years, 68% were female, and 8% were currently using oral glucocorticoids. At baseline, BMD for the entire cohort was greater than the expected values for the population at the lumbar spine (mean Z-score 0.7, P<0.001) and total body (0.5, P<0.001) and similar to expected values at the femoral neck (0.2, P=0.14) and total hip (0.2, P=0.14). BMD did not change at any of these four sites (P>0.19) over 2 years in the longitudinal study. In the intervention study, vitamin D supplements had no effect on BMD, and therefore we pooled the data from all participants. BMD did not change over 1 year at the spine, total hip, or femoral neck (P>0.3), but decreased by 0.7% (95% confidence interval 0.3-1.1) at the total body (P=0.019).

CONCLUSIONS

BMD was normal at baseline, and there was no consistent evidence of accelerated bone loss over 1-2 years, regardless of baseline vitamin D status. Patients with sarcoidosis not using oral glucocorticoids do not need routine monitoring of BMD.

Calcium and vitamin D in sarcoidosis: is supplementation safe?

Granulomas in sarcoidosis express high levels of 1α-hydroxylase, an enzyme that catalyzes the hydroxylation of 25-OH vitamin D to its active form, 1,25(OH)2 vitamin D. Overproduction of 1α-hydroxylase is held responsible for the development of hypercalcemia in sarcoidosis patients. Corticosteroids are used as first-line treatment in organ-threatening sarcoidosis. In this light, osteoporosis prevention with calcium and vitamin D (CAD) supplementation is often warranted. However, sarcoidosis patients are at risk for hypercalcemia, and CAD supplementation affects the calcium metabolism. We studied calcium and vitamin D disorders in a large cohort of sarcoidosis patients and investigated if CAD supplementation is safe. Retrospectively, data of 301 sarcoidosis patients from July 1986 to June 2009 were analyzed for serum calcium, 25-hydroxy vitamin D (25-(OH)D), 1,25-dihydroxy vitamin D (1,25(OH)2 D), and use of CAD supplementation. Disease activity of sarcoidosis was compared with serum levels of vitamin D. Hypercalcemia occurred in 8%. A significant negative correlation was found between 25-(OH)D and disease activity of sarcoidosis measured by somatostatin receptor scintigraphy. In our study, 5 of the 104 CAD-supplemented patients developed hypercalcemia, but CAD supplementation was not the cause of hypercalcemia. Patients without CAD supplementation were at higher risk for developing hypercalcemia. During CAD supplementation, no hypercalcemia developed as a result of supplementation. Hypovitaminosis D seems to be related with more disease activity of sarcoidosis and, therefore, could be a potential risk factor for disease activity of sarcoidosis. Thus, vitamin D-deficient sarcoidosis patients should be supplemented.

Cutaneous sarcoidosis: an intriguing model of immune dysregulation

Sarcoidosis is a systemic granulomatous disease characterized by the presence of non-caseating granulomas. Its etiology remains obscure. A plausible hypothesis suggests that a complex interplay of host factors, infectious processes, and non-infectious environmental factors, matched with a susceptible genetic background, results in a pathway that leads to systemic granulomatous inflammation. Although presentations of sarcoidosis vary enormously, multi-organ involvement is a common feature. Cutaneous involvement occurs in about 25% of patients with protean manifestations and variable prognoses. Skin manifestations are divided into specific lesions with histopathologically evident non-caseating granulomas and nonspecific lesions arising from a reactive process that does not form granulomas. A peculiar form of cutaneous sarcoidosis is represented by sarcoidal lesions at sites of trauma that has caused scarring. The pathogenesis of scar sarcoidosis remains unknown. Scar sarcoidosis is also associated with herpes zoster infection, surgery, and tattooing. Such heterogeneous events, along with those at the sites of chronic lymphedema, thermal burns, radiation dermatitis, and vaccinations, occur on areas of vulnerable skin labeled "immunocompromised districts". Numerous options are available for the treatment of cutaneous sarcoidosis. Although corticosteroids remain the treatment of choice for initial systemic therapy, other nonsteroidal agents have proven effective and therefore useful for long-term management. Tumor necrosis factor-α antagonists such as infliximab may have a role in the treatment of cutaneous sarcoidosis, especially in refractory cases that are resistant to standard regimens. Elucidation of the relationship of sarcoidal granulomas with malignancy and immunity may facilitate a better understanding of some pathomechanisms operating in neoplastic and immunity-related disorders.

Current best practice in the management of pulmonary and systemic sarcoidosis

Sarcoidosis is a systemic inflammatory disease of unknown etiology that is characterized by the presence of granulomatous inflammation in affected tissues. It can affect essentially any organ system but shows a predilection for the lungs, eyes, and skin. Accurate epidemiological data are not available in the USA, but sarcoidosis is considered a 'rare disease' (prevalence less than 200,000). However, recent epidemiologic studies indicate that regional prevalence is much higher than previously estimated, especially among African American women. Additionally, mortality rates of patients with sarcoidosis are increasing by 3% per year over the past two decades. The most common causes of death are attributed to progressive lung disease and cardiac sarcoidosis, and the health of the patients is further compromised by other systemic manifestations. As such, the management of sarcoidosis requires a collaborative multidisciplinary approach. We aim to discuss the principles of managing sarcoidosis, including standards of care relating to pulmonary disease as well as recent advances relating to the detection and treatment of extrapulmonary manifestations.

Sarcoidosis

Sarcoidosis is a systemic disease of unknown cause that is characterised by the formation of immune granulomas in various organs, mainly the lungs and the lymphatic system. Studies show that sarcoidosis might be the result of an exaggerated granulomatous reaction after exposure to unidentified antigens in individuals who are genetically susceptible. Several new insights have been made, particularly with regards to the diagnosis and care of some important manifestations of sarcoidosis. The indications for endobronchial ultrasound in diagnosis and for PET in the assessment of inflammatory activity are now better specified. Recognition of unexplained persistent disabling symptoms, fatigue, small-fibre neurological impairment, cognitive failure, and changes to health state and quality of life, has improved. Mortality in patients with sarcoidosis is higher than that of the general population, mainly due to pulmonary fibrosis. Predicted advances for the future are finding the cause of sarcoidosis, and the elucidation of relevant biomarkers, reliable endpoints, and new efficient treatments, particularly in patients with refractory sarcoidosis, lung fibrosis, and those with persistent disabling symptoms.

Randomised controlled trial of vitamin D supplementation in sarcoidosis

OBJECTIVES

The role vitamin D intake/production plays in sarcoidosis-associated hypercalcaemia is uncertain. However, authoritative reviews have recommended avoiding sunlight exposure and vitamin D supplements, which might lead to adverse skeletal outcomes from vitamin D insufficiency. We investigated the effects of vitamin D supplementation on surrogate measures of skeletal health in patients with sarcoidosis and vitamin D insufficiency.

DESIGN

Randomised, placebo-controlled trial.

SETTING

Clinical research centre.

PARTICIPANTS

27 normocalcaemic patients with sarcoidosis and 25-hydroxyvitamin D (25OHD) <50 nmol/L.

INTERVENTION

50 000 IU weekly cholecalciferol for 4 weeks, then 50 000 IU monthly for 11 months or placebo.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary endpoint was the change in serum calcium over 12 months, and secondary endpoints included measurements of calcitropic hormones, bone turnover markers and bone mineral density (BMD).

RESULTS

The mean age of participants was 57 years and 70% were women. The mean (SD) screening 25OHD was 35 (12) and 38 (9) nmol/L in the treatment and control groups, respectively. Vitamin D supplementation increased 25OHD to 94 nmol/L after 4 weeks, 84 nmol/L at 6 months and 78 nmol/L at 12 months, while levels remained stable in the control group. 1,25-Dihydroxy vitamin D levels were significantly different between the groups at 4 weeks, but not at 6 or 12 months. There were no between-groups differences in albumin-adjusted serum calcium, 24 h urine calcium, markers of bone turnover, parathyroid hormone or BMD over the trial. One participant developed significant hypercalcaemia after 6 weeks (total cholecalciferol dose 250 000 IU).

CONCLUSIONS

In patients with sarcoidosis and 25OHD <50 nmol/L, vitamin D supplements did not alter average serum calcium or urine calcium, but had no benefit on surrogate markers of skeletal health and caused one case of significant hypercalcaemia.

TRIAL REGISTRATION

This trial is registered at the Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au). The registration number is ACTRN12607000364471, date of registration 5/7/2007.

Severe hypercalcemia unmasked by Vitamin D in a patient with sarcoidosis

Severe hypercalcemia is uncommon in clinical practice and is usually due to primary hperparathyroidism or malignancy. We present a patient who presented with severe hypercalcemia with renal failure; further evaluation of which revealed the diagnosis of sarcoidosis. This case is presented in view of the rarity of presentation of sarcoidosis with hypercalcemic crisis.

The role of vitamin D supplementation in patients with rheumatic diseases

Vitamin D is a dietary vitamin that can also be synthesized in adequate amounts from cholesterol in most mammals exposed to sunlight. Vitamin D has classical roles in calcium and phosphate metabolism, and thus the skeleton; however, this molecule also has nonclassical effects that might influence the function of the immune, cardiovascular and endocrine systems. Vitamin D deficiency, due to insufficient sunlight exposure, dietary uptake and/or abnormalities in its metabolism, has been associated with rheumatic diseases, and both the classical and nonclassical effects of vitamin D might be of relevance to patients with rheumatic disease. However, conclusive data from intervention trials demonstrating the relationship between vitamin D levels and pathogenetic processes separate from classical effects of this molecule are lacking. Furthermore, the majority of studies linking vitamin D to health outcomes, harmful or beneficial, are observational in nature, linking clinical events to vitamin D exposure or serum levels of vitamin D metabolites. Evidence from high quality, prospective, double-blind, placebo-controlled, randomized trials should be obtained before vitamin D supplementation is recommended in the treatment of the many rheumatic conditions in which deficiency of this compound has been implicated. Herein, we review the evidence for vitamin D supplementation in the management of patients with rheumatic diseases.

Current and emerging pharmacological treatments for sarcoidosis: a review

The treatment of sarcoidosis is not standardized. Because sarcoidosis may never cause significant symptoms or organ dysfunction, treatment is not mandatory. When treatment is indicated, oral corticosteroids are usually recommended because they are highly likely to be effective in a relative short period of time. However, because sarcoidosis is often a chronic condition, long-term treatment with corticosteroids may cause significant toxicity. Therefore, corticosteroid sparing agents are often indicated in patients requiring chronic therapy. This review outlines the indications for treatment, corticosteroid treatment, and corticosteroid sparing treatments for sarcoidosis.

Calcium metabolism and correcting calcium deficiencies

Calcium is the most abundant cation in the human body, of which approximately 99% occurs in bone, contributing to its rigidity and strength. Bone also functions as a reservoir of Ca for its role in multiple physiologic and biochemical processes. This article aims to provide a thorough understanding of the absorptive mechanisms and factors affecting these processes to enable one to better appreciate an individual's Ca needs, and to provide a rationale for correcting Ca deficiencies. An overview of Ca requirements and suggested dosing regimens is presented, with discussion of various Ca preparations and potential toxicities of Ca treatment.

Vitamin D metabolism and signaling in the immune system

Vitamin D has emerged as a pleiotropic regulator of human physiology, and recent work has revealed that it has several roles in control of human immune system function. Vitamin D was originally characterized for its role in calcium homeostasis, and the active form, 1,25-dihydroxyvitamin D (1,25D), can be produced in the kidney by 1α-hydroxylation of circulating 25-hydroxyvitamin D catalyzed by the enzyme CYP27B1. Renal CYP27B1 expression is regulated by calcium regulatory inputs, and 1,25D produced in the kidney was thought to function largely as an endocrine hormone. However, it is now clear that CYP27B1 is expressed in numerous tissues, and that 1,25D acts at several sites in the body in an intracrine or paracrine manner. In particular, both CYP27B1 and the vitamin D receptor (VDR) are expressed in several cell types in the immune system, where CYP27B1 production is controlled by a number of immune-specific inputs. Recent research has opened several windows on the molecular mechanisms by which 1,25D signaling regulates both innate and adaptive immune responses in humans. Moreover, intervention trials are beginning to provide evidence that vitamin D supplementation can bolster clinical responses to infection. This review will discuss recent developments in our understanding of how immune signaling controls local vitamin D metabolism and how, in turn, the 1,25D-bound VDR modulates immune system function. A particular emphasis will be placed on the interplay between vitamin D signaling and signaling through different classes of pattern recognition receptors in the production of antimicrobial peptides during innate immune responses to microbial infection.

Regulation of intracrine production of 1,25-dihydroxyvitamin D and its role in innate immune defense against infection

Vitamin D was discovered as the cure for nutritional rickets. Classically, hormonal 1,25-dihydroxyvitamin D (1,25D), produced in the kidney by CYP27B1-catalyzed 1α-hydroxylation from its circulating 25-hydroxy precursor, has been considered to function as a critical endocrine regulator of calcium homeostasis. However, our appreciation of vitamin D metabolism and physiological function has evolved dramatically in recent years. First, vitamin D is now recognized as a pleiotropic regulator of human physiology, with emerging roles in cancer chemoprevention, cardio-protection, and, in particular, regulation of immune system functions. Moreover, CYP27B1 is very widely expressed, and evidence is rapidly accumulating that local CYP27B1-catalyzed production of 1,25D, controlled by tissue-specific signals, is critical for its physiological actions. Nowhere is this more apparent than in the innate immune system, where recent studies have shown that CYP27B1 expression is under control of several immune signaling pathways, and that signaling by 1,25D in macrophages and dendritic cells is critical for innate immune responses to infection. This review will describe our current knowledge of the signaling pathways that lead to 1,25D production in the immune system and the downstream signaling events it controls in response to pathogen recognition.

Sarcoidosis

Sarcoidosis is a multisystem, granulomatous disease. In this article, the various clinical manifestations, approach to, and management of, pulmonary and extrapulmonary sarcoidosis are reviewed.