Sarcoidosis is a highly variable, systemic granulomatous disease of hitherto unknown aetiology. The GenPhenReSa (Genotype-Phenotype Relationship in Sarcoidosis) project represents a European multicentre study to investigate the influence of genotype on disease phenotypes in sarcoidosis.The baseline phenotype module of GenPhenReSa comprised 2163 Caucasian patients with sarcoidosis who were phenotyped at 31 study centres according to a standardised protocol.From this module, we found that patients with acute onset were mainly female, young and of Scadding type I or II. Female patients showed a significantly higher frequency of eye and skin involvement, and complained more of fatigue. Based on multidimensional correspondence analysis and subsequent cluster analysis, patients could be clearly stratified into five distinct, yet undescribed, subgroups according to predominant organ involvement: 1) abdominal organ involvement, 2) ocular-cardiac-cutaneous-central nervous system disease involvement, 3) musculoskeletal-cutaneous involvement, 4) pulmonary and intrathoracic lymph node involvement, and 5) extrapulmonary involvement.These five new clinical phenotypes will be useful to recruit homogenous cohorts in future biomedical studies.

Functional predictions and protein network analyses suggest a prominent role of the drug-targetable IL23/Th17 signaling pathway in the genetic etiology of sarcoidosis. Our findings reveal a substantial genetic overlap of sarcoidosis with diverse immune-mediated inflammatory disorders, which could be of relevance for the clinical application of modern therapeutics.

There are significant and clinically relevant differences in the severity of symptoms, restrictions of activities of daily living and impairment of health status between the patients with isolated pulmonary and pulmonary plus extrapulmonary sarcoidosis. Patients with pulmonary plus extrapulmonary sarcoidosis are more impaired in all these categories.

SummaryBackgroundUntil now, a proper biomarker(s) to evaluate sarcoidosis activity has not been recognized. The aims of this study were to evaluate the sensitivity and specificity of the two biomarkers of sarcoidosis activity already in use (serum angiotensin converting enzyme – ACE and serum chitotriosidase) in a population of 430 sarcoidosis patients. The activities of these markers were also analyzed in a group of 264 healthy controls.MethodsFour hundred and thirty biopsy positive sarcoidosis patients were divided into groups with active and inactive disease, and groups with acute or chronic disease. In a subgroup of 55 sarcoidosis patients, activity was also assessed by F-18 fluorodeoxyglucose positron emission tomography (18F-FDG-PET) scanning. Both serum chitotriosidase and ACE levels showed non-normal distribution, so nonparametric tests were used in statistical analysis.ResultsSerum chitotriosidase activities were almost 6 times higher in patients with active sarcoidosis than in healthy controls and inactive disease. A serum chitotriosidase value of 100 nmol/mL/h had the sensitivity of .5% and specificity of 70.0%. A serum ACE activity cutoff value of 32.0 U/L had the sensitivity of 66.0% and the specificity of 54%. A statistically significant correlation was obtained between the focal granulomatous activity detected on 18F-FDG PET/CT and serum chitotriosidase levels, but no such correlation was found with ACE. The levels of serum chitotriosidase activity significantly correlated with the disease duration (P < 0.0001). Also, serum chitotriosidase significantly correlated with clinical outcome status (COS) categories (ρ =0.272, P =0.001).ConclusionsSerum chitotriosidase proved to be a reliable biomarker of sarcoidosis activity and disease chronicity.

Sarcoidosis is an inflammatory granulomatous disease that is characterized by diverse organ system manifestations, a variable clinical course, and a predilection for affecting relatively young adults worldwide. Abnormalities on chest radiographs are detected in 85% to 95% of patients who have sarcoidosis. Approximately 20% to 50% of patients who have sarcoidosis present with respiratory symptoms, including dyspnea, cough, chest pain, and tightness of the chest. The clinical course and manifestations of pulmonary sarcoidosis are protean: spontaneous remission occurs in approximately two thirds of patients; up to 30% of patients have chronic course of the lung disease, resulting in progressive, (sometimes life-threatening) loss of lung function. Morbidity that correlates to sarcoidosis occurs in 1% to 4% of patients.