Coexistence of immune-mediated diseases in sarcoidosis. Frequency and clinical significance in 1737 patients

Rheumatologic Perspectives on Sarcoidosis: Predicting Sarcoidosis-Associated Arthritis Through Comprehensive Clinical and Laboratory Assessment

Background/Objectives: The primary aim of our study was to evaluate the demographic, clinical, and laboratory characteristics of sarcoidosis patients with musculoskeletal symptoms; investigate the relationship between arthritis development and various laboratory parameters (such as vitamin D, liver enzymes, and ACE levels); and compare the sarcoidosis-associated arthritis cases with those without. We also explored the factors influencing arthritis development and the role of biopsy in diagnosing sarcoidosis within rheumatology practice. Methods: This retrospective study analyzed 147 sarcoidosis patients from 2000 to 2024, categorized by the presence (n = 45) or absence (n = 102) of arthritis. Demographic, clinical, and laboratory data, including biopsy results, were collected and compared. Results: The mean age was 56.02 ± 11.21 years, with a mean disease duration of 134.33 ± 56.98 months. Females constituted 86.4% of the cohort. All of the patients presented musculoskeletal involvement. Pulmonary involvement was present in 93.7% of cases, and extrapulmonary involvement included the skin (21.20%), the eyes (14.30%), and peripheral lymphadenopathy (10.6%). Methotrexate was the most common treatment after corticosteroids. In the arthritis group, diabetes mellitus was more frequent (p = 0.024), the GGT levels were higher (p = 0.044), and the 25-hydroxyvitamin D levels (p = 0.002) and the DLCO Adj (p = 0.039) were lower. Multivariable regression showed diabetes mellitus (p = 0.028, OR: 4.805, 95% CI: 1.025-22.518) and low 25-hydroxyvitamin D levels (p = 0.034, OR: 0.914, 95% CI: 0.841-0.993) as factors influencing arthritis development. The other parameters showed no significant differences. Conclusions: This study identified significant clinical, demographic, and laboratory differences between sarcoidosis patients with and without arthritis. The patients with sarcoidosis-associated arthritis exhibited a higher frequency of diabetes mellitus, lower levels of 25-hydroxyvitamin D, and elevated GGT levels. Additionally, the lower DLCO values in the patients with arthritis indicate a more severe impact on pulmonary function, underscoring the importance of comprehensive pulmonary evaluation in this subgroup.

Sarcoidosis and its relation to other immune-mediated diseases: Epidemiological insights

Several epidemiological studies show a co-occurrence of sarcoidosis with other immune-mediated diseases (IMD). There are many similarities between sarcoidosis and IMDs in their geographical distribution and risk factors. Understanding these similarities and identifying the differences can help us to better understand sarcoidosis and put it into context with other IMDs. In this review, we present the current knowledge about the overlap between sarcoidosis and other IMDs derived from epidemiological studies. Epidemiologic methods utilize study design and statistical analysis to describe the patterns in data and, ideally, identify causal relationships between an exposure and a health outcome. We discuss how study design and analysis may affect the interpretation of epidemiological studies on this topic and highlight some theories that attempt to explain the relation between sarcoidosis and other IMDs.

Overlap syndromes in sarcoidosis: Unveiling the masquerader

As a multi system granulomatous disease, clinical presentations of sarcoidosis are highly variable. In the absence of a stereotypical clinical presentation such as asymptomatic bilateral hilar adenopathy, Lofgren's syndrome, or lupus pernio, a diagnosis of sarcoidosis typically requires 1) compatible clinical presentation, 2) histologic evidence of granulomatous inflammation, and 3) the exclusion of other causes. The clinical presentation of sarcoidosis is often nonspecific and a variety of other causes of granulomatous inflammation can make diagnosing sarcoidosis a challenge for clinicians. "Overlap syndromes" are often used to describe clinical presentations of sarcoidosis that share histologic and clinical features of other diseases, or when the diagnosis of sarcoidosis is made in association with the coexistence of another diagnosis with similar clinical or histologic findings. Because of the risk of diagnostic delay and diagnostic errors, it is vital for clinicians to be familiar with overlap syndromes in sarcoidosis. The coexistence of sarcoidosis with other diseases can also significantly impact disease management and outcomes. This article will review the most current published data on overlap syndromes in sarcoidosis to aid clinicians in diagnosing and managing these complex patients.

Sarcoidosis and Cancer: The Role of the Granulomatous Reaction as a Double-Edged Sword

Background/Objectives: The relationship between sarcoidosis and the occurrence of neoplasia deserves to be investigated, but this relation has been observed in different and heterogeneous populations, leading to conflicting data. To clarify the causal relationship between these two diseases, different risk factors (e.g., smoking), concurrent comorbidities, corticosteroid therapy, and metastasis development-as an expression of cancer aggressiveness-were investigated. Methods: In a retrospective study on 287 sarcoidosis outpatients at the Pneumological Department of the Gemelli Foundation (Rome, Italy) between 2000 and 2024, the diagnosis of cancer was recorded in 36 subjects (12.5%). Results: The reciprocal timeline of the diseases showed three different scenarios: (1) cancer preceding sarcoidosis or sarcoid-like reactions (63.8%); (2) cancer arising after sarcoidosis diagnosis (8.3%); and (3) sarcoidosis accompanying the onset of malignancy (27.8%). Only two subjects with sarcoidosis and cancer showed metastasis, and one of them was affected by lymphoma. Conclusions: These data suggest that granulomatous inflammation due to sarcoidosis may assume an ambivalent role as a "double-edged sword", according to the M1/M2 macrophage polarization model: it represents a protective shield, preventing the formation of metastasis through the induction of immune surveillance against cancer while, on the other hand, it can be a risk factor for carcinogenesis due to the persistence of a chronic active inflammatory status. Low-dose steroid treatment was administered in only 31.6% of the cancer-sarcoidosis subjects for less than six months to control inflammation activity, with no promotive effect on carcinogenesis observed.

Sarcoidosis versus Granulomatous and Lymphocytic Interstitial Lung Disease in Common Variable Immunodeficiency: A Comparative Review

Sarcoidosis and Granulomatous and Lymphocytic Interstitial Lung Diseases (GLILD) are two rare entities primarily characterised by the development of Interstitial Lung Disease (ILD) in the context of systemic immune dysregulation. These two conditions partially share the immunological background and pathologic findings, with granuloma as the main common feature. In this narrative review, we performed a careful comparison between sarcoidosis and GLILD, with an overview of their main similarities and differences, starting from a clinical perspective and ending with a deeper look at the immunopathogenesis and possible target therapies. Sarcoidosis occurs in immunocompetent individuals, whereas GLILD occurs in patients affected by common variable immunodeficiency (CVID). Moreover, peculiar extrapulmonary manifestations and radiological and histological features may help distinguish the two diseases. Despite that, common pathogenetic pathways have been suggested and both these disorders can cause progressive impairment of lung function and variable systemic granulomatous and non-granulomatous complications, leading to significant morbidity, reduced quality of life, and survival. Due to the rarity of these conditions and the extreme clinical variability, there are still many open questions concerning their pathogenesis, natural history, and optimal management. However, if studied in parallel, these two entities might benefit from each other, leading to a better understanding of their pathogenesis and to more tailored treatment approaches.

The causal relationship between sarcoidosis and autoimmune diseases: a bidirectional Mendelian randomization study in FinnGen

Background

Sarcoidosis has been considered to be associated with many autoimmune diseases (ADs), but the cause-and-effect relationship between these two diseases has not been fully explored. Therefore, the objective of this study is to explore the possible genetic association between sarcoidosis and ADs.

Methods

We conducted a bidirectional Mendelian randomization (MR) study using genetic variants associated with ADs and sarcoidosis (4,041 cases and 371,255 controls) from the FinnGen study. The ADs dataset comprised 96,150 cases and 281,127 controls, encompassing 44 distinct types of autoimmune-related diseases. Subsequently, we identified seven diseases within the ADs dataset with a case size exceeding 3,500 and performed subgroup analyses on these specific diseases.

Results

The MR evidence supported the causal association of genetic predictors of ADs with an increased risk of sarcoidosis (OR = 1.79, 95% CI = 1.59 to 2.02, P IVW-FE = 1.01 × 10-21), and no reverse causation (OR = 1.05, 95% CI 0.99 to 1.12, P IVW-MRE = 9.88 × 10-2). Furthermore, subgroup analyses indicated that genetic predictors of type 1 diabetes mellitus (T1DM), celiac disease, and inflammatory bowel disease (IBD) were causally linked to an elevated risk of sarcoidosis (All P < 6.25 × 10-3). Conversely, genetic predictors of sarcoidosis showed causal associations with a higher risk of type 1 diabetes mellitus (P < 6.25 × 10-3).

Conclusion

The present study established a positive causal relationship between genetic predictors of ADs (e.g. T1DM, celiac disease, and IBD) and the risk of sarcoidosis, with no evidence of reverse causation.

Causal influence of celiac disease on the risk of sarcoidosis: A Mendelian randomization study

Observational research shows a link between celiac disease (CeD) and sarcoidosis, but the causal link between CeD and sarcoidosis is still unknown. A two-sample Mendelian randomization (MR) study was conducted to ascertain the causal connection between the 2 disorders. In our two-sample MR analysis, we identified independent genetic variants associated with CeD using publicly accessible GWAS data from people of European ancestry. Summary data for sarcoidosis were obtained from the FinnGen Consortium, the UK-Biobank, and a large GWAS dataset. To assess the association between CeD and sarcoidosis, our MR analysis used inverse variance weighted (IVW) as the primary method, incorporating the MR-Egger, weighted median (WM), and MR-PRESSO (outliers test) as a complementary method. In order to ensure that the findings were reliable, several sensitivity analyses were performed. Our study indicated that CeD had a significant causal relationship with sarcoidosis (IVW odds ratio (OR) = 1.13, 95% confidence interval (CI): 1.07-1.20, P = 5.58E-05; WM OR = 1.12, 95% CI: 1.03-1.23, P = 1.03E-02; MR-Egger OR = 1.07, 95% CI: 0.96-1.19, P = 2.20E-01). Additionally, we obtain the same results in the duplicated datasets as well, which makes our results even more reliable. The results of this investigation did not reveal any evidence of horizontal pleiotropy or heterogeneity. Our MR analysis showed a causal effect between CeD and an elevated risk of sarcoidosis. Further study is still needed to confirm the findings and look into the processes underlying these relationships.

Hematologic and Oncologic Aspects of Sarcoidosis: Some of the Least Studied but Most Common Dilemmas

The hematologic system is frequently involved in sarcoidosis. Lymphopenia is the most common hematologic manifestation noted, although anemia and thrombocytopenia also occur. The etiology of these common manifestations can be direct granulomatous infiltration of bone marrow, lymph nodes, or spleen or related to immunologic dysfunction. Although not life threatening, these problems can lead to cytopenias requiring close monitoring in patients receiving a variety of disease treatments. The relationship between sarcoidosis and malignancy remains complex. However, some sarcoidosis patients are at increased risk for the development of malignancies, particularly lymphomas and gastrointestinal cancers. Conversely, cancer patients can experience an increase in the likelihood for the development of breast cancer and lymphomas.

Autoimmune thrombotic thrombocytopenic purpura associated with disseminated sarcoidosis: A case report

Sarcoidosis is an inflammatory disease known to be associated with multiple autoimmune disorders. There is a restricted number of descriptions of the association between sarcoidosis and autoimmune thrombotic thrombocytopenic purpura (aTTP). We present the case of a 63-year-old woman admitted to the hospital to investigate a possible sarcoidosis who had hemolytic anemia and thrombocytopenia, with low ADAMTS13 activity and anti-ADAMTS13 antibodies, leading to a diagnosis of aTTP. Sarcoidosis was later confirmed and the two conditions evolved separately after 6 months, questioning the link between them. Clinicians should be aware of this rare cause of thrombocytopenia in patients with sarcoidosis, as aTTP is a life-threatening condition.

Hematological involvement in sarcoidosis: from cytopenias to lymphoma

INTRODUCTION

We present an updated overview of the hematological involvementassociated with sarcoidosis, including a management approach forcytopenias and revisiting the association with hematologicalmalignancies.

AREAS COVERED

Theetiology of cytopenias in sarcoidosis can be attributed to two majoretiopathogenic mechanisms: infiltration of hematopoietic organs suchas the spleen and bone marrow, and autoimmune-mediated cytopenias.With respect to the association with hematological malignancies, itrequires careful evaluation of patients from a chronologicalperspective. Patients must be classified into one of three pathogenicscenarios, including preexisting hematological malignancies,synchronous development of malignancy and sarcoidosis due to commonpredisposing factors, or sarcoidosis as a predisposing factor formalignancies.

EXPERT OPINION

The association between sarcoidosis and hematologic involvement isbest understood as a pathogenic continuum, with cytopenias andhematologic neoplasms intertwined due to various etiopathogenicmechanisms. These mechanisms include sarcoid infiltration ofhematopoietic organs, common predisposing immunogenetics for thedevelopment of autoimmune cytopenias and malignancies, and anincreased risk of neoplasm development in patients with autoimmunecytopenias. Collaboration among the main specialties involved in theclinical management of these patients is crucial for an earlymonitoring and management.

Demographics, Cutaneous Manifestations, and Comorbidities Associated with Progressive Cutaneous Sarcoidosis: A Retrospective Cohort Study

Background: Sarcoidosis is a multisystem granulomatous disease with a wide variety of presentations and clinical courses. Cutaneous manifestations and comorbidities associated with sarcoid prognosis remain understudied. Methods: An EPIC query was run for patients age 18+ at the Johns Hopkins Hospital with a diagnosis of sarcoidosis of the skin according to the ICD-10-CM code D86.3. Data were obtained from a population-based sample of 240 patients from 2015 to 2020. Results: A total of 240 patients were included in the cohort study. The mean (SD) age was 43.76 (11.72) years, and 30% of participants were male; 76.25% of patients identified as black, 19.58% as white, and 4.17% as other. The average age of onset in remissive patients was significantly higher than progressive (47 ± 12 vs. 40 ± 10, p = 0.0005); 49% of black patients experienced progressive sarcoid compared to 32.6% of white patients (p = 0.028). Progressive disease was associated with the presence of lupus pernio (aOR = 3.29, 95% CI, 1.60-6.77) and at least one autoimmune comorbidity (aOR 6.831, 95% CI 1.819-11.843). Conclusions: When controlling for patient demographics, lupus pernio and the presence of at least one autoimmune condition were associated with progressive cutaneous sarcoidosis.

Autoimmune comorbidities associated with sarcoidosis: a case-control study in the All of Us research program

Objective

The degree to which sarcoidosis patients are affected by autoimmune diseases is poorly understood. Prior studies of autoimmune co-morbidities in sarcoidosis have focused on populations outside the USA or have been impeded by small sample sizes and limited scope. This case-control study evaluated the association between sarcoidosis and autoimmune diseases in a large, diverse cohort based in the USA.

Methods

We used data from the All of Us research programme to conduct a case-control study involving patients ≥18 years old, from 2018 to the present, diagnosed with sarcoidosis. Sarcoidosis cases and age-, sex- and race-matched controls were identified in a 1:4 ratio. Autoimmune co-morbidities were compared between sarcoidosis patients and controls in univariable and multivariable analyses using logistic regression. The degree of association was measured using the odds ratio (OR).

Results

A total of 1408 sarcoidosis cases and 5632 controls were included in this study. Seven of 24 examined autoimmune diseases were significantly associated with sarcoidosis in our multivariable analysis (P < 0.05). The composite variable of any autoimmune disease was also significantly associated with sarcoidosis (OR = 2.29, P < 0.001).

Conclusion

We demonstrate an association between sarcoidosis and multiple autoimmune diseases in a large and diverse cohort based in the USA. These results underscore the need for careful screening of sarcoidosis patients for concomitant autoimmune disease.

Comorbidities of sarcoidosis

Sarcoidosis is a heterogeneous disease, which can affect virtually every body organ, even though lungs and intra thoracic lymph nodes are almost universally affected. The presence of noncaseating granulomas is the histopathological hallmark of the disease, and clinical picture depends on the organs affected. Data about interaction between sarcoidosis and comorbidities, such as cardiovascular and pulmonary diseases, autoimmune disorders, malignancy and drug-related adverse events are limited. Several lung conditions can be associated with sarcoidosis, such as pulmonary hypertension and fibrosis, making it difficult sometimes the differentiation between complications and distinctive pathologies. Their coexistence may complicate the diagnosis of sarcoidosis and contribute to the highly variable and unpredictable natural history, particularly if several diseases are recognised. A thorough assessment of specific disorders that can be associated with sarcoidosis should always be carried out, and future studies will need to evaluate sarcoidosis not only as a single disorder, but also in the light of possible concomitant conditions.Key messagesComorbidities in sarcoidosis are common, especially cardiovascular and pulmonary diseases.In the diagnostic workup, a distinction must be made between sarcoidosis-related complaints and complaints caused by other separate disorders. It can be very difficult to distinguish between complications of sarcoidosis and other concomitant conditions.The coexistence of multiple conditions may complicate the diagnosis of sarcoidosis, affect its natural course and response to treatment.

Sarcoidosis

Sarcoidosis is a systemic autoimmune disease that is associated with the development of non-caseating granulomas. The disease especially affects the lymph nodes, lungs, skin and eyes. It is an infrequent but not rare disease, especially in northern Europe, the United States and India. Sarcoidosis affects more women and is diagnosed between the ages of 30 and 50. Etiopathogenically, it is closely linked to environmental factors, especially occupational exposures. Clinically, it stands out for a wide variety of presentation phenotypes (casual diagnosis, involvement of a single organ or systemic presentation). The diagnosis of sarcoidosis is complex and requires the integration of clinical, analytical, radiological, and histolopathogical data carried out by multidisciplinary clinical units. The evolution of the disease is variable, as is the indication for systemic treatment, based on the use of corticosteroids as first-line option, the use of immunosuppressants as second-line therapy, and anti-TNF agents in severe and/or refractory cases.

Safety, patient acceptance and diagnostic accuracy of ultrasound core needle biopsy of parotid or submandibular glands in primary Sjögren's syndrome with suspected salivary gland lymphoma

Background

Enlargement of the major salivary glands (SGs) is a major risk factor for B-cell lymphoma among patients with primary Sjögren’s syndrome (pSS). Ultrasound-guided core needle biopsy (US-guided CNB) could be a novel technique to manage SG enlargement among patients with pSS.

Objective

Accordingly, this study’s main aim was to evaluate the safety, patient tolerance and diagnostic accuracy of US-guided CNB procedure for patients with pSS with major SG enlargement.

Methods

Patients with clinical diagnosis of pSS and a clinical indication for SG biopsy consecutively underwent US-guided CNB between September 2019 and June 2021. These patients were evaluated clinically 1, 2 and 12 weeks after US-guided CNB. Patients were asked to complete a questionnaire about postprocedural complications as well as periprocedural pain, using the Visual Analogue Scale. Complications were categorised as transient (<12 weeks) or persistent (≥12 weeks).

Results

US-guided CNB was performed on 30 major salivary glands (22 parotid glands and 8 submandibular glands). The procedure was well tolerated. Transient complications—such as haematoma, swelling—were observed among 43% of patients, and mean periprocedural pain was low. However, no persistent complications were reported during the study’s follow-up period.

Conclusion

US-guided CNB represents a novel approach for the management of patients with pSS with SG enlargement. The procedure showed remarkable patient safety and tolerance, allowing adequate glandular sampling and a definite diagnosis for almost all participating patients without long-term complications.

Association of spondyloarthritis and sarcoidosis: A retrospective observational population-based matched cohort study

OBJECTIVES

To investigate the association between spondyloarthritis (SpA) and sarcoidosis.

METHODS

An observational retrospective population-based matched cohort study was conducted. Using data from the Spanish Minimum Basic Data Set. All the admissions of patients with SpA reported between 1999 and 2015 were analysed and a control group matched by age, sex and year of admission was selected. Crude and age- and sex-adjusted incidence rates for sarcoidosis were calculated. Generalized linear models were used for trend analysis and unconditional logistic regression models for calculating crude and adjusted odds ratios (ORs) to assess the association between sarcoidosis and SpA.

RESULTS

The study database contained data on 214,280 hospitalisations: 107,140 admissions of patients with SpA and 107,140 of patients without SpA. Overall, 220 of the admissions were of patients with sarcoidosis: 133 (0.12%) in the SpA group and 87 (0.08%) in the non-SpA group (P<0.05). The incidence rates of sarcoidosis were 2.68 and 1.64 per 100,000 per year in the SpA and non-SpA groups, respectively. The trend was similar in the two cohorts. Regarding potential associations between SpA and sarcoidosis, the crude and adjusted ORs were 1.52 (95% CI: 1.16-2.01) and 1.50 (95% CI: 1.14-1.97) overall in patients with SpA, with adjusted ORs of 1.42 (95% CI: 1.03-1.94) and 1.81 (95% CI: 1.29-2.55) in patients with ankylosing spondylitis and psoriatic arthritis, respectively.

CONCLUSIONS

There is a relationship that is not due to chance between sarcoidosis and SpA and specifically that sarcoidosis is significantly associated with ankylosing spondylitis and psoriatic arthritis.

Sarcoidosis and autoimmunity

PURPOSE OF REVIEW

Sarcoidosis is a poorly understood multisystem granulomatous disease that frequently involves the lungs but can affect any organ system. In this review, we summarize recent developments in the understanding of the immune dysregulation seen in sarcoidosis and propose a new expanded definition of human autoimmunity in sarcoidosis, and the implications it would have on treating sarcoidosis with targeted immunotherapy regimens in the future.

RECENT FINDINGS

Sarcoidosis has been linked to infectious organisms like Mycobacterium and Cutibacterium, and certain manifestations of sarcoidosis have been linked to specific HLA alleles, but the overall pathogenesis remains uncertain. Sarcoidosis patients have similar patterns of cellular immune dysregulation seen in other autoimmune diseases like rheumatoid arthritis, and recent large-scale population studies show that sarcoidosis frequently presents with other autoimmune diseases.

SUMMARY

Advancements in the understanding of sarcoidosis support its consideration as an autoimmune disease. Sarcoidosis patients carry a higher risk of comorbid autoimmune conditions which offers an excellent opportunity to further understand autoimmunity and explore biologic therapies in sarcoidosis treatment, and furthermore will better targeted immunotherapy regimens for sarcoidosis patients in the future.